1
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Wolf F. Scheme for Quantum-Logic Based Transfer of Accuracy in Polarizability Measurement for Trapped Ions Using a Moving Optical Lattice. PHYSICAL REVIEW LETTERS 2024; 132:083202. [PMID: 38457716 DOI: 10.1103/physrevlett.132.083202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Revised: 10/09/2023] [Accepted: 01/10/2024] [Indexed: 03/10/2024]
Abstract
Optical atomic clocks based on trapped ions suffer from systematic frequency shifts of the clock transition due to interaction with blackbody radiation from the environment. These shifts can be compensated if the blackbody radiation spectrum and the differential dynamic polarizability is known to a sufficient precision. Here, we present a new measurement scheme, based on quantum logic that allows a direct transfer of precision for polarizability measurements from one species to the other. This measurement circumvents the necessity of calibrating laser power below the percent level, which is the limitation for state-of-the-art polarizability measurements in trapped ions. Furthermore, the presented technique allows one to reference the polarizability transfer to hydrogenlike ions for which the polarizability can be calculated with high precision.
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Affiliation(s)
- Fabian Wolf
- Physikalisch-Technische Bundesanstalt, 38116 Braunschweig, Germany
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2
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Kromer K, Lyu C, Door M, Filianin P, Harman Z, Herkenhoff J, Indelicato P, Keitel CH, Lange D, Novikov YN, Schweiger C, Eliseev S, Blaum K. Observation of a Low-Lying Metastable Electronic State in Highly Charged Lead by Penning-Trap Mass Spectrometry. PHYSICAL REVIEW LETTERS 2023; 131:223002. [PMID: 38101362 DOI: 10.1103/physrevlett.131.223002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Revised: 10/09/2023] [Accepted: 10/17/2023] [Indexed: 12/17/2023]
Abstract
Highly charged ions (HCIs) offer many opportunities for next-generation clock research due to the vast landscape of available electronic transitions in different charge states. The development of extreme ultraviolet frequency combs has enabled the search for clock transitions based on shorter wavelengths in HCIs. However, without initial knowledge of the energy of the clock states, these narrow transitions are difficult to be probed by lasers. In this Letter, we provide experimental observation and theoretical calculation of a long-lived electronic state in Nb-like Pb^{41+} that could be used as a clock state. With the mass spectrometer PENTATRAP, the excitation energy of this metastable state is directly determined as a mass difference at an energy of 31.2(8) eV, corresponding to one of the most precise relative mass determinations to date with a fractional uncertainty of 4×10^{-12}. This experimental result agrees within 1σ with two partially different ab initio multiconfiguration Dirac-Hartree-Fock calculations of 31.68(13) eV and 31.76(35) eV, respectively. With a calculated lifetime of 26.5(5.3) days, the transition from this metastable state to the ground state bears a quality factor of 1.1×10^{23} and allows for the construction of a HCI clock with a fractional frequency instability of <10^{-19}/sqrt[τ].
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Affiliation(s)
- Kathrin Kromer
- Max-Planck-Institut für Kernphysik, 69117 Heidelberg, Germany
| | - Chunhai Lyu
- Max-Planck-Institut für Kernphysik, 69117 Heidelberg, Germany
| | - Menno Door
- Max-Planck-Institut für Kernphysik, 69117 Heidelberg, Germany
| | - Pavel Filianin
- Max-Planck-Institut für Kernphysik, 69117 Heidelberg, Germany
| | - Zoltán Harman
- Max-Planck-Institut für Kernphysik, 69117 Heidelberg, Germany
| | - Jost Herkenhoff
- Max-Planck-Institut für Kernphysik, 69117 Heidelberg, Germany
| | - Paul Indelicato
- Laboratoire Kastler Brossel, Sorbonne Université, CNRS, ENS-PSL Research University, Collège de France, Paris, France
| | | | - Daniel Lange
- Max-Planck-Institut für Kernphysik, 69117 Heidelberg, Germany
| | - Yuri N Novikov
- Department of Physics, St Petersburg State University, St. Petersburg 198504, Russia
- NRC "Kurchatov Institute"-Petersburg Nuclear Physics Institute, Gatchina 188300, Russia
| | | | - Sergey Eliseev
- Max-Planck-Institut für Kernphysik, 69117 Heidelberg, Germany
| | - Klaus Blaum
- Max-Planck-Institut für Kernphysik, 69117 Heidelberg, Germany
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3
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Rehbehn NH, Rosner MK, Berengut JC, Schmidt PO, Pfeifer T, Gu MF, López-Urrutia JRC. Narrow and Ultranarrow Transitions in Highly Charged Xe Ions as Probes of Fifth Forces. PHYSICAL REVIEW LETTERS 2023; 131:161803. [PMID: 37925712 DOI: 10.1103/physrevlett.131.161803] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Revised: 07/21/2023] [Accepted: 09/15/2023] [Indexed: 11/07/2023]
Abstract
Optical frequency metrology in atoms and ions can probe hypothetical fifth forces between electrons and neutrons by sensing minute perturbations of the electronic wave function induced by them. A generalized King plot has been proposed to distinguish them from possible standard model effects arising from, e.g., finite nuclear size and electronic correlations. Additional isotopes and transitions are required for this approach. Xenon is an excellent candidate, with seven stable isotopes with zero nuclear spin, however it has no known visible ground-state transitions for high resolution spectroscopy. To address this, we have found and measured twelve magnetic-dipole lines in its highly charged ions and theoretically studied their sensitivity to fifth forces as well as the suppression of spurious higher-order standard model effects. Moreover, we identified at 764.8753(16) nm a E2-type ground-state transition with 500 s excited state lifetime as a potential clock candidate further enhancing our proposed scheme.
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Affiliation(s)
| | | | - Julian C Berengut
- Max-Planck-Institut für Kernphysik, D-69117 Heidelberg, Germany
- School of Physics, University of New South Wales, Sydney, New South Wales 2052, Australia
| | - Piet O Schmidt
- Physikalisch-Technische Bundesanstalt, D-38116 Braunschweig, Germany
- Leibniz Universität Hannover, D-30167 Hannover, Germany
| | - Thomas Pfeifer
- Max-Planck-Institut für Kernphysik, D-69117 Heidelberg, Germany
| | - Ming Feng Gu
- Space Science Laboratory, University of California, Berkeley, California 94720, USA
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4
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Lipphardt B, Walkemeyer P, Kazda M, Rahm J, Weyers S. Continuous optical generation of microwave signals for fountain clocks. APPLIED OPTICS 2023; 62:7628-7632. [PMID: 37855470 DOI: 10.1364/ao.503631] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Accepted: 09/17/2023] [Indexed: 10/20/2023]
Abstract
For the optical generation of ultrastable microwave signals for fountain clocks, we developed a setup based on a cavity stabilized laser and a commercial frequency comb. The robust system, in operation since 2020, is locked to a 100 MHz output frequency of a hydrogen maser and provides an ultrastable 9.6 GHz signal for the interrogation of atoms in two cesium fountain clocks, acting as primary frequency standards. Measurements reveal that the system provides a phase noise level that enables quantum projection noise limited fountain frequency instabilities at the low 10-14(τ/s)-1/2 level. At the same time, it offers largely maintenance-free operation.
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5
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Loh W, Maxson RT, Medeiros AP, West GN, Juodawlkis PW, McConnell RP. Optical frequency averaging of light. OPTICS EXPRESS 2023; 31:25507-25514. [PMID: 37710435 DOI: 10.1364/oe.488699] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Accepted: 06/30/2023] [Indexed: 09/16/2023]
Abstract
The use of averaging has long been known to reduce noise in statistically independent systems that exhibit similar levels of stochastic fluctuation. This concept of averaging is general and applies to a wide variety of physical and man-made phenomena such as particle motion, shot noise, atomic clock stability, measurement uncertainty reduction, and methods of signal processing. Despite its prevalence in use for reducing statistical uncertainty, such averaging techniques so far remain comparatively undeveloped for application to light. We demonstrate here a method for averaging the frequency uncertainty of identical laser systems as a means to narrow the spectral linewidth of the resulting radiation. We experimentally achieve a reduction of frequency fluctuations from 40 Hz to 28 Hz by averaging two separate laser systems each locked to a fiber resonator. Only a single seed laser is necessary here as acousto-optic modulation is used to enable independent control of the second path. This technique of frequency averaging provides an effective solution to overcome the linewidth constraints of a single laser alone, particularly when limited by fundamental noise sources such as thermal noise, irrespective of the spectral shape of noise.
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6
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Sundar B, Barberena D, Orioli AP, Chu A, Thompson JK, Rey AM, Lewis-Swan RJ. Bosonic Pair Production and Squeezing for Optical Phase Measurements in Long-Lived Dipoles Coupled to a Cavity. PHYSICAL REVIEW LETTERS 2023; 130:113202. [PMID: 37001062 DOI: 10.1103/physrevlett.130.113202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2022] [Accepted: 02/14/2023] [Indexed: 06/19/2023]
Abstract
We propose to simulate bosonic pair creation using large arrays of long-lived dipoles with multilevel internal structure coupled to an undriven optical cavity. Entanglement between the atoms, generated by the exchange of virtual photons through a common cavity mode, grows exponentially fast and is described by two-mode squeezing of effective bosonic quadratures. The mapping between an effective bosonic model and the natural spin description of the dipoles allows us to realize the analog of optical homodyne measurements via straightforward global rotations and population measurements of the electronic states, and we propose to exploit this for quantum-enhanced sensing of an optical phase (common and differential between two ensembles). We discuss a specific implementation based on Sr atoms and show that our sensing protocol is robust to sources of decoherence intrinsic to cavity platforms. Our proposal can open unique opportunities for next-generation optical atomic clocks.
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Affiliation(s)
- Bhuvanesh Sundar
- Center for Theory of Quantum Matter, University of Colorado, Boulder, Colorado 80309, USA
- JILA, NIST, Department of Physics, University of Colorado, Boulder, Colorado 80309, USA
| | - Diego Barberena
- Center for Theory of Quantum Matter, University of Colorado, Boulder, Colorado 80309, USA
- JILA, NIST, Department of Physics, University of Colorado, Boulder, Colorado 80309, USA
| | - Asier Piñeiro Orioli
- Center for Theory of Quantum Matter, University of Colorado, Boulder, Colorado 80309, USA
- JILA, NIST, Department of Physics, University of Colorado, Boulder, Colorado 80309, USA
| | - Anjun Chu
- Center for Theory of Quantum Matter, University of Colorado, Boulder, Colorado 80309, USA
- JILA, NIST, Department of Physics, University of Colorado, Boulder, Colorado 80309, USA
| | - James K Thompson
- JILA, NIST, Department of Physics, University of Colorado, Boulder, Colorado 80309, USA
| | - Ana Maria Rey
- Center for Theory of Quantum Matter, University of Colorado, Boulder, Colorado 80309, USA
- JILA, NIST, Department of Physics, University of Colorado, Boulder, Colorado 80309, USA
| | - Robert J Lewis-Swan
- Homer L. Dodge Department of Physics and Astronomy, The University of Oklahoma, Norman, Oklahoma 73019, USA
- Center for Quantum Research and Technology, The University of Oklahoma, Norman, Oklahoma 73019, USA
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7
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Fathollahi L, Wu F, Pongracic B. Gravitational redshift test using Rb clocks of eccentric GPS satellites. Heliyon 2023; 9:e13178. [PMID: 36747516 PMCID: PMC9898677 DOI: 10.1016/j.heliyon.2023.e13178] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2022] [Revised: 11/27/2022] [Accepted: 01/19/2023] [Indexed: 01/26/2023] Open
Abstract
This paper reports a test of gravitational redshift, which is a consequence of the Einstein equivalence principle, using the Rb clocks of GPS Block IIF satellites. The fractional deviation in the gravitational redshift was measured using 6,640 days of data from three Rb clocks onboard GPS Block IIF satellites. The systematic effects related to orbital uncertainty, temperature, and magnetic field were modeled conservatively. The fractional deviation in the gravitational redshift from the general relativity prediction was measured with ( 0.23 ± 1.34 ) × 10 - 3 at one sigma.
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Affiliation(s)
- Loghman Fathollahi
- SNARS Laboratory, School of Instrumentation and Optoelectronic Engineering, Beihang University, Beijing, China
| | - Falin Wu
- SNARS Laboratory, School of Instrumentation and Optoelectronic Engineering, Beihang University, Beijing, China
- Corresponding author.
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8
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Kobayashi T, Takamizawa A, Akamatsu D, Kawasaki A, Nishiyama A, Hosaka K, Hisai Y, Wada M, Inaba H, Tanabe T, Yasuda M. Search for Ultralight Dark Matter from Long-Term Frequency Comparisons of Optical and Microwave Atomic Clocks. PHYSICAL REVIEW LETTERS 2022; 129:241301. [PMID: 36563281 DOI: 10.1103/physrevlett.129.241301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Accepted: 10/05/2022] [Indexed: 06/17/2023]
Abstract
We search for ultralight scalar dark matter candidates that induce oscillations of the fine structure constant, the electron and quark masses, and the quantum chromodynamics energy scale with frequency comparison data between a ^{171}Yb optical lattice clock and a ^{133}Cs fountain microwave clock that span 298 days with an uptime of 15.4%. New limits on the couplings of the scalar dark matter to electrons and gluons in the mass range from 10^{-22} to 10^{-20} eV/c^{2} are set, assuming that each of these couplings is the dominant source of the modulation in the frequency ratio. The absolute frequency of the ^{171}Yb clock transition is also determined as 518 295 836 590 863.69(28) Hz, which is one of the important contributions toward a redefinition of the second in the International System of Units.
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Affiliation(s)
- Takumi Kobayashi
- National Metrology Institute of Japan (NMIJ), National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Umezono, Tsukuba, Ibaraki 305-8563, Japan
| | - Akifumi Takamizawa
- National Metrology Institute of Japan (NMIJ), National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Umezono, Tsukuba, Ibaraki 305-8563, Japan
| | - Daisuke Akamatsu
- National Metrology Institute of Japan (NMIJ), National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Umezono, Tsukuba, Ibaraki 305-8563, Japan
- Department of Physics, Graduate School of Engineering Science, Yokohama National University, 79-5 Tokiwadai, Hodogaya-ku, Yokohama 240-8501, Japan
| | - Akio Kawasaki
- National Metrology Institute of Japan (NMIJ), National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Umezono, Tsukuba, Ibaraki 305-8563, Japan
| | - Akiko Nishiyama
- National Metrology Institute of Japan (NMIJ), National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Umezono, Tsukuba, Ibaraki 305-8563, Japan
| | - Kazumoto Hosaka
- National Metrology Institute of Japan (NMIJ), National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Umezono, Tsukuba, Ibaraki 305-8563, Japan
| | - Yusuke Hisai
- Department of Physics, Graduate School of Engineering Science, Yokohama National University, 79-5 Tokiwadai, Hodogaya-ku, Yokohama 240-8501, Japan
| | - Masato Wada
- National Metrology Institute of Japan (NMIJ), National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Umezono, Tsukuba, Ibaraki 305-8563, Japan
| | - Hajime Inaba
- National Metrology Institute of Japan (NMIJ), National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Umezono, Tsukuba, Ibaraki 305-8563, Japan
| | - Takehiko Tanabe
- National Metrology Institute of Japan (NMIJ), National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Umezono, Tsukuba, Ibaraki 305-8563, Japan
| | - Masami Yasuda
- National Metrology Institute of Japan (NMIJ), National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Umezono, Tsukuba, Ibaraki 305-8563, Japan
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9
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Guo Z, Lu Z, Meng S, Lin W, Zhang H, Liu B, Liu H, Yao Y. Analog transmission of time-frequency signal in atmospheric turbulence environment. OPTICS EXPRESS 2022; 30:34077-34091. [PMID: 36242429 DOI: 10.1364/oe.467947] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Accepted: 08/22/2022] [Indexed: 06/16/2023]
Abstract
The high-precision time-frequency transfer of the optical atomic clock signals over ground-to-satellite and terrestrial free-space laser paths is of great significance in the fields of fundamental and applied sciences. However, the phase noises caused by atmospheric turbulence severely degrade the measurement precision. In this paper, a new method to simulate the transmission of time-frequency signal propagating through atmospheric turbulence is investigated. An analog transmission system comparable to the practical out-field link has been demonstrated, which can provide a deep insight into the phase distortion of time-frequency signal of free-space optical communication links.
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10
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Loh W, Kharas D, Maxson R, West GN, Medeiros A, Braje D, Juodawlkis PW, McConnell R. Cooling of an integrated Brillouin laser below the thermal limit. OPTICS EXPRESS 2022; 30:22562-22571. [PMID: 36224951 DOI: 10.1364/oe.451622] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Accepted: 05/17/2022] [Indexed: 06/16/2023]
Abstract
Photonically integrated resonators are promising as a platform for enabling ultranarrow linewidth lasers in a compact form factor. Owing to their small size, these integrated resonators suffer from thermal noise that limits the frequency stability of the optical mode to ∼100 kHz. Here, we demonstrate an integrated stimulated Brillouin scattering (SBS) laser based on a large mode-volume annulus resonator that realizes an ultranarrow thermal-noise-limited linewidth of 270 Hz. In practice, yet narrower linewidths are required before integrated lasers can be truly useful for applications such as optical atomic clocks, quantum computing, gravitational wave detection, and precision spectroscopy. To this end, we employ a thermorefractive noise suppression technique utilizing an auxiliary laser to reduce our SBS laser linewidth to 70 Hz. This demonstration showcases the possibility of stabilizing the thermal motion of even the narrowest linewidth chip lasers to below 100 Hz, thereby opening the door to making integrated microresonators practical for the most demanding future scientific endeavors.
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11
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Chae E, Nakashima K, Yoshioka K. Dual optical frequency combs with ultra-low relative phase jitters from 550 nm to 1020 nm for precision spectroscopy. OPTICS EXPRESS 2022; 30:18703-18712. [PMID: 36221666 DOI: 10.1364/oe.458735] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Accepted: 05/04/2022] [Indexed: 06/16/2023]
Abstract
Here, ultra-low relative phase jitters over a wide optical spectrum were achieved for dual Ti:Sapphire optical frequency combs. The two optical frequency combs were independently phase-locked to a Sr optical lattice clock laser delivered through a commercial optical fiber network. We confirmed that the relative phase jitters between the two combs integrated from 8.3 mHz to 200 kHz were below 1 rad, corresponding to a relative linewidth of below 8.3 mHz, over the entire wavelength of the optical frequency combs ranging from 550 nm to 1020 nm. Our work paves the way for ultrahigh-precision dual-comb spectroscopy covering a wide optical spectral range with a simple setup, and provides an absolute optical frequency reference with great stability over a wide range of wavelengths.
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12
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Orenes DB, Sewell RJ, Lodewyck J, Mitchell MW. Improving Short-Term Stability in Optical Lattice Clocks by Quantum Nondemolition Measurement. PHYSICAL REVIEW LETTERS 2022; 128:153201. [PMID: 35499904 DOI: 10.1103/physrevlett.128.153201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Revised: 03/20/2022] [Accepted: 03/23/2022] [Indexed: 06/14/2023]
Abstract
We propose a multimeasurement estimation protocol for quantum nondemolition (QND) measurements in a Rabi clock interferometer. The method is well suited for current state-of-the-art optical lattice clocks with QND measurement capabilities. The protocol exploits the correlations between multiple nondestructive measurements of the initially prepared coherent spin state. A suitable Gaussian estimator for the clock laser detuning is presented, and an analytic expression for the sensitivity of the protocol is derived. We use this analytic expression to optimize the protocol using available experimental parameters, achieving an improvement of 7.9 dB with respect to the standard quantum limit in terms of clock stability. We also discuss the measurement back-action effects of our protocol into the atomic state.
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Affiliation(s)
- Daniel Benedicto Orenes
- ICFO-Institut de Ciències Fotòniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels (Barcelona), Spain
| | - Robert J Sewell
- ICFO-Institut de Ciències Fotòniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels (Barcelona), Spain
| | - Jérôme Lodewyck
- LNE-SYRTE, Observatoire de Paris, Université PSL, CNRS, Sorbonne Université, 61 avenue de l'Observatoire, F-75014 Paris, France
| | - Morgan W Mitchell
- ICFO-Institut de Ciències Fotòniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels (Barcelona), Spain
- ICREA-Institució Catalana de Recerca i Estudis Avançats, 08010 Barcelona, Spain
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13
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Mao X, Yang F, Wei F, Shi J, Cai J, Cai H. A Low Temperature Coefficient Time-to-Digital Converter with 1.3 ps Resolution Implemented in a 28 nm FPGA. SENSORS 2022; 22:s22062306. [PMID: 35336481 PMCID: PMC8953977 DOI: 10.3390/s22062306] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Revised: 03/07/2022] [Accepted: 03/15/2022] [Indexed: 02/04/2023]
Abstract
Time-to-digital converter (TDC) is the key technology to realize accurate time delay measurement in high-precision optical fiber time-frequency transmission and synchronization, optical sensing and many scientific applications. The performance of FPGA-TDC based on the carry chain is sensitive to the operating temperature. This paper presents a parallel multichain cross segmentation method, without multitime measurements, which merges multichain into an equivalent chain, achieving low temperature coefficient and maintaining high precision. The equivalent chain breaks the limit of the intrinsic cell delay of a single carry chain, improves the precision and reduces the impact of temperature variation significantly. A two-channel TDC based on parallel multichain cross segmentation method is implemented in a 28 nm fabrication process Kintex-7 FPGA. The results show that the performance of TDC is improved with the increase of the number of chains. The 10-chain TDC with 1.3 ps resolution, 4.6 ps single-shot precision performs much better than the plain TDC with 11.4 ps resolution, 8.7 ps single-shot precision. The resolution is stable with 0.0002 ps/°C temperature coefficient under an operating temperature range from 25 °C to 70 °C. Moreover, the proposed method reduces the complexity of the circuit and the resource usage.
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Affiliation(s)
- Xiangyu Mao
- Key Laboratory of Space Laser Communication and Detection Technology, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China; (X.M.); (F.W.); (J.S.); (H.C.)
| | - Fei Yang
- Key Laboratory of Space Laser Communication and Detection Technology, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China; (X.M.); (F.W.); (J.S.); (H.C.)
- Correspondence:
| | - Fang Wei
- Key Laboratory of Space Laser Communication and Detection Technology, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China; (X.M.); (F.W.); (J.S.); (H.C.)
| | - Jiawen Shi
- Key Laboratory of Space Laser Communication and Detection Technology, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China; (X.M.); (F.W.); (J.S.); (H.C.)
| | - Jian Cai
- Institute of Microelectronics, Chinese Academy of Sciences, Beijing 100029, China;
| | - Haiwen Cai
- Key Laboratory of Space Laser Communication and Detection Technology, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China; (X.M.); (F.W.); (J.S.); (H.C.)
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14
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Gozzard DR, Howard LA, Dix-Matthews BP, Karpathakis SFE, Gravestock CT, Schediwy SW. Ultrastable Free-Space Laser Links for a Global Network of Optical Atomic Clocks. PHYSICAL REVIEW LETTERS 2022; 128:020801. [PMID: 35089751 DOI: 10.1103/physrevlett.128.020801] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Accepted: 12/02/2021] [Indexed: 06/14/2023]
Abstract
A global network of optical atomic clocks will enable unprecedented measurement precision in fields including tests of fundamental physics, dark matter searches, geodesy, and navigation. Free-space laser links through the turbulent atmosphere are needed to fully exploit this global network, by enabling comparisons to airborne and spaceborne clocks. We demonstrate frequency transfer over a 2.4 km atmospheric link with turbulence comparable to that of a ground-to-space link, achieving a fractional frequency stability of 6.1×10^{-21} in 300 s of integration time. We also show that clock comparison between ground and low Earth orbit will be limited by the stability of the clocks themselves after only a few seconds of integration. This significantly advances the technologies needed to realize a global timescale network of optical atomic clocks.
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Affiliation(s)
- D R Gozzard
- International Centre for Radio Astronomy Research, ICRAR M468, The University of Western Australia, 35 Stirling Hwy, Crawley 6009, Australia
- Australian Research Council Centre of Excellence for Engineered Quantum Systems, Department of Physics, School of Physics, Mathematics & Computing, The University of Western Australia, 35 Stirling Hwy, Crawley 6009, Australia
| | - L A Howard
- International Centre for Radio Astronomy Research, ICRAR M468, The University of Western Australia, 35 Stirling Hwy, Crawley 6009, Australia
| | - B P Dix-Matthews
- International Centre for Radio Astronomy Research, ICRAR M468, The University of Western Australia, 35 Stirling Hwy, Crawley 6009, Australia
- Australian Research Council Centre of Excellence for Engineered Quantum Systems, Department of Physics, School of Physics, Mathematics & Computing, The University of Western Australia, 35 Stirling Hwy, Crawley 6009, Australia
| | - S F E Karpathakis
- International Centre for Radio Astronomy Research, ICRAR M468, The University of Western Australia, 35 Stirling Hwy, Crawley 6009, Australia
| | - C T Gravestock
- International Centre for Radio Astronomy Research, ICRAR M468, The University of Western Australia, 35 Stirling Hwy, Crawley 6009, Australia
| | - S W Schediwy
- International Centre for Radio Astronomy Research, ICRAR M468, The University of Western Australia, 35 Stirling Hwy, Crawley 6009, Australia
- Australian Research Council Centre of Excellence for Engineered Quantum Systems, Department of Physics, School of Physics, Mathematics & Computing, The University of Western Australia, 35 Stirling Hwy, Crawley 6009, Australia
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15
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Schioppo M, Kronjäger J, Silva A, Ilieva R, Paterson JW, Baynham CFA, Bowden W, Hill IR, Hobson R, Vianello A, Dovale-Álvarez M, Williams RA, Marra G, Margolis HS, Amy-Klein A, Lopez O, Cantin E, Álvarez-Martínez H, Le Targat R, Pottie PE, Quintin N, Legero T, Häfner S, Sterr U, Schwarz R, Dörscher S, Lisdat C, Koke S, Kuhl A, Waterholter T, Benkler E, Grosche G. Comparing ultrastable lasers at 7 × 10 -17 fractional frequency instability through a 2220 km optical fibre network. Nat Commun 2022; 13:212. [PMID: 35017500 PMCID: PMC8752831 DOI: 10.1038/s41467-021-27884-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Accepted: 12/14/2021] [Indexed: 11/24/2022] Open
Abstract
Ultrastable lasers are essential tools in optical frequency metrology enabling unprecedented measurement precision that impacts on fields such as atomic timekeeping, tests of fundamental physics, and geodesy. To characterise an ultrastable laser it needs to be compared with a laser of similar performance, but a suitable system may not be available locally. Here, we report a comparison of two geographically separated lasers, over the longest ever reported metrological optical fibre link network, measuring 2220 km in length, at a state-of-the-art fractional-frequency instability of 7 × 10-17 for averaging times between 30 s and 200 s. The measurements also allow the short-term instability of the complete optical fibre link network to be directly observed without using a loop-back fibre. Based on the characterisation of the noise in the lasers and optical fibre link network over different timescales, we investigate the potential for disseminating ultrastable light to improve the performance of remote optical clocks.
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Affiliation(s)
- M Schioppo
- National Physical Laboratory (NPL), Teddington, TW11 0LW, UK.
| | - J Kronjäger
- National Physical Laboratory (NPL), Teddington, TW11 0LW, UK.
| | - A Silva
- National Physical Laboratory (NPL), Teddington, TW11 0LW, UK
| | - R Ilieva
- National Physical Laboratory (NPL), Teddington, TW11 0LW, UK
| | - J W Paterson
- National Physical Laboratory (NPL), Teddington, TW11 0LW, UK
| | - C F A Baynham
- National Physical Laboratory (NPL), Teddington, TW11 0LW, UK
| | - W Bowden
- National Physical Laboratory (NPL), Teddington, TW11 0LW, UK
| | - I R Hill
- National Physical Laboratory (NPL), Teddington, TW11 0LW, UK
| | - R Hobson
- National Physical Laboratory (NPL), Teddington, TW11 0LW, UK
| | - A Vianello
- National Physical Laboratory (NPL), Teddington, TW11 0LW, UK
| | | | - R A Williams
- National Physical Laboratory (NPL), Teddington, TW11 0LW, UK
| | - G Marra
- National Physical Laboratory (NPL), Teddington, TW11 0LW, UK
| | - H S Margolis
- National Physical Laboratory (NPL), Teddington, TW11 0LW, UK
| | - A Amy-Klein
- Laboratoire de Physique des Lasers (LPL), Université Paris 13, CNRS, Villetaneuse, France
| | - O Lopez
- Laboratoire de Physique des Lasers (LPL), Université Paris 13, CNRS, Villetaneuse, France
| | - E Cantin
- Laboratoire de Physique des Lasers (LPL), Université Paris 13, CNRS, Villetaneuse, France
- LNE-SYRTE, Observatoire de Paris - Université PSL, CNRS, Sorbonne Université, LNE, Paris, France
| | - H Álvarez-Martínez
- LNE-SYRTE, Observatoire de Paris - Université PSL, CNRS, Sorbonne Université, LNE, Paris, France
- Real Instituto y Observatorio de la Armada (ROA), 11100, San Fernando, Cádiz, Spain
| | - R Le Targat
- LNE-SYRTE, Observatoire de Paris - Université PSL, CNRS, Sorbonne Université, LNE, Paris, France
| | - P E Pottie
- LNE-SYRTE, Observatoire de Paris - Université PSL, CNRS, Sorbonne Université, LNE, Paris, France
| | | | - T Legero
- Physikalisch-Technische Bundesanstalt (PTB), Bundesallee 100, 38116, Braunschweig, Germany
| | - S Häfner
- Physikalisch-Technische Bundesanstalt (PTB), Bundesallee 100, 38116, Braunschweig, Germany
| | - U Sterr
- Physikalisch-Technische Bundesanstalt (PTB), Bundesallee 100, 38116, Braunschweig, Germany
| | - R Schwarz
- Physikalisch-Technische Bundesanstalt (PTB), Bundesallee 100, 38116, Braunschweig, Germany
| | - S Dörscher
- Physikalisch-Technische Bundesanstalt (PTB), Bundesallee 100, 38116, Braunschweig, Germany
| | - C Lisdat
- Physikalisch-Technische Bundesanstalt (PTB), Bundesallee 100, 38116, Braunschweig, Germany
| | - S Koke
- Physikalisch-Technische Bundesanstalt (PTB), Bundesallee 100, 38116, Braunschweig, Germany
| | - A Kuhl
- Physikalisch-Technische Bundesanstalt (PTB), Bundesallee 100, 38116, Braunschweig, Germany
| | - T Waterholter
- Physikalisch-Technische Bundesanstalt (PTB), Bundesallee 100, 38116, Braunschweig, Germany
| | - E Benkler
- Physikalisch-Technische Bundesanstalt (PTB), Bundesallee 100, 38116, Braunschweig, Germany
| | - G Grosche
- Physikalisch-Technische Bundesanstalt (PTB), Bundesallee 100, 38116, Braunschweig, Germany
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16
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Lange R, Peshkov AA, Huntemann N, Tamm C, Surzhykov A, Peik E. Lifetime of the ^{2}F_{7/2} Level in Yb^{+} for Spontaneous Emission of Electric Octupole Radiation. PHYSICAL REVIEW LETTERS 2021; 127:213001. [PMID: 34860090 DOI: 10.1103/physrevlett.127.213001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Revised: 09/27/2021] [Accepted: 10/15/2021] [Indexed: 06/13/2023]
Abstract
We report a measurement of the radiative lifetime of the ^{2}F_{7/2} level of ^{171}Yb^{+} that is coupled to the ^{2}S_{1/2} ground state via an electric octupole transition. The radiative lifetime is determined to be 4.98(25)×10^{7} s, corresponding to 1.58(8) yr. The result reduces the relative uncertainty in this exceptionally long excited state lifetime by 1 order of magnitude with respect to previous experimental estimates. Our method is based on the coherent excitation of the corresponding transition and avoids limitations through competing decay processes. The explicit dependence on the laser intensity is eliminated by simultaneously measuring the resonant Rabi frequency and the induced quadratic Stark shift. Combining the result with information on the dynamic differential polarizability permits a calculation of the transition matrix element to infer the radiative lifetime.
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Affiliation(s)
- R Lange
- Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig, Germany
| | - A A Peshkov
- Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig, Germany
- Institut für Mathematische Physik, Technische Universität Braunschweig, Mendelssohnstraße 3, 38106 Braunschweig, Germany
| | - N Huntemann
- Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig, Germany
| | - Chr Tamm
- Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig, Germany
| | - A Surzhykov
- Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig, Germany
- Institut für Mathematische Physik, Technische Universität Braunschweig, Mendelssohnstraße 3, 38106 Braunschweig, Germany
- Laboratory for Emerging Nanometrology, Langer Kamp 6a/b, 38106 Braunschweig, Germany
| | - E Peik
- Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig, Germany
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17
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Simultaneous bicolor interrogation in thulium optical clock providing very low systematic frequency shifts. Nat Commun 2021; 12:5171. [PMID: 34453046 PMCID: PMC8397736 DOI: 10.1038/s41467-021-25396-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Accepted: 08/05/2021] [Indexed: 11/25/2022] Open
Abstract
Optical atomic clocks have already overcome the eighteenth decimal digit of instability and uncertainty, demonstrating incredible control over external perturbations of the clock transition frequency. At the same time, there is an increasing demand for atomic (ionic) transitions and new interrogation and readout protocols providing minimal sensitivity to external fields and possessing practical operational wavelengths. One of the goals is to simplify the clock operation while maintaining the relative uncertainty at a low 10−18 level achieved at the shortest averaging time. This is especially important for transportable and envisioned space-based optical clocks. Here, we demonstrate implementation of a synthetic frequency approach for a thulium optical clock with simultaneous optical interrogation of two clock transitions. Our experiment shows suppression of the quadratic Zeeman shift by at least three orders of magnitude. The effect of the tensor lattice Stark shift in thulium can also be reduced to below 10−18 in fractional frequency units. This makes the thulium optical clock almost free from hard-to-control systematic shifts. The “simultaneous” protocol demonstrates very low sensitivity to the cross-talks between individual clock transitions during interrogation and readout. There are continuous efforts in improving the stability and systematic shifts of optical clocks. Here the authors demonstrate thulium optical clock utilizing bicolor scheme involving interrogation of both hyperfine levels and they are able to cancel the quadratic Zeeman shift.
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18
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Beloy K. Prospects of a Pb^{2+} Ion Clock. PHYSICAL REVIEW LETTERS 2021; 127:013201. [PMID: 34270290 PMCID: PMC10202158 DOI: 10.1103/physrevlett.127.013201] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Accepted: 05/17/2021] [Indexed: 05/24/2023]
Abstract
We propose a high-performance atomic clock based on the 1.81 PHz transition between the ground and first-excited state of doubly ionized lead. Utilizing an even isotope of lead, both clock states have I=J=F=0, where I, J, and F are the conventional quantum numbers specifying nuclear, electronic, and total angular momentum, respectively. The clock states are nondegenerate and completely immune to nonscalar perturbations, including first order Zeeman and electric quadrupole shifts. Additionally, the proposed clock is relatively insusceptible to other frequency shifts (blackbody radiation, second order Zeeman, Doppler), accommodates "magic" rf trapping, and is robust against decoherence mechanisms that can otherwise limit clock stability. By driving the transition as a two-photon E1+M1 process, the accompanying probe Stark shift is appreciable yet manageable for practical Rabi frequencies.
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19
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Wu R, Yang F, Sun Y, Cheng N, Wang J, Wei F, Gui Y, Cai H. Absolute phase marking technology and fiber-optic remote coherent phase transmission. OPTICS EXPRESS 2021; 29:14041-14057. [PMID: 33985130 DOI: 10.1364/oe.419695] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Accepted: 04/13/2021] [Indexed: 06/12/2023]
Abstract
Fiber-optic time and frequency synchronization technology demonstrates ultra-high synchronization performance and has been gradually applied in various fields. Based on frequency synchronization, this study addressed the problems of period ambiguity and initial phase uncertainty of the phase signal to realize the coherent transmission of the phase. An absolute phase marking technology was developed based on high-speed digital logic with zero-crossing detection and an optimized control strategy. It can realize picosecond-level absolute phase marking and provide a picosecond-level ultra-low peak-to-peak jitter pulse marking signal to eliminate phase period ambiguity and determine initial phase and transmission delay. Thus, by combining the high-precision phase measurement capability of the synchronized frequency signal and long-distance ambiguity elimination capability of the pulse-per-second signal, a high-precision remote coherent phase transmission over an optical fiber is realized. After frequency synchronization, the peak-to-peak jitter between the local and remote phase-marking signals can be only 3.3 ps within 10,000 s measurement time. The uncertainty of the coherent phase transmission is 2.577 ps. This technology can significantly improve the phase coherence of fiber-optic time and frequency transmission and provide a new approach to achieve peak-to-peak picosecond-level reference phase marking and high-precision fiber-optic remote coherent phase transmission. This demonstrates broad application prospects in coherence fields such as radar networking.
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20
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Wu H, Zhang Z, Chen S, Sun K, Sun J, Reid DT, Lu Z, Zhang J. Development of a deep-ultraviolet pulse laser source operating at 234 nm for direct cooling of Al + ion clocks. OPTICS EXPRESS 2021; 29:11468-11478. [PMID: 33984925 DOI: 10.1364/oe.421684] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Accepted: 03/19/2021] [Indexed: 06/12/2023]
Abstract
We report on the development of a 250-MHz 234 nm deep-ultraviolet pulse source based on a flexible wavelength-conversion scheme. The scheme is based on a frequency-doubled optical parametric oscillator (FD-OPO) together with a cascaded frequency conversion process. We use a χ(2) nonlinear envelope equation to guide the design of an intra-cavity OPO crystal, demonstrating a flexible broadband tunable feature and providing as high as watt-level of a frequency-doubled signal output centered at 850 nm, which is served as an input wave for the cascaded frequency conversion process. As much as 3.0 mW of an average power at 234 nm is obtained, with an rms power stability of better than 1% over 20 minutes. This deep-ultraviolet pulse laser source can be used for many applications in quantum optics and for direct laser cooling of Al+ ion clocks.
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21
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Frequency ratio measurements at 18-digit accuracy using an optical clock network. Nature 2021; 591:564-569. [PMID: 33762766 DOI: 10.1038/s41586-021-03253-4] [Citation(s) in RCA: 72] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Accepted: 01/18/2021] [Indexed: 02/01/2023]
Abstract
Atomic clocks are vital in a wide array of technologies and experiments, including tests of fundamental physics1. Clocks operating at optical frequencies have now demonstrated fractional stability and reproducibility at the 10-18 level, two orders of magnitude beyond their microwave predecessors2. Frequency ratio measurements between optical clocks are the basis for many of the applications that take advantage of this remarkable precision. However, the highest reported accuracy for frequency ratio measurements has remained largely unchanged for more than a decade3-5. Here we operate a network of optical clocks based on 27Al+ (ref. 6), 87Sr (ref. 7) and 171Yb (ref. 8), and measure their frequency ratios with fractional uncertainties at or below 8 × 10-18. Exploiting this precision, we derive improved constraints on the potential coupling of ultralight bosonic dark matter to standard model fields9,10. Our optical clock network utilizes not just optical fibre11, but also a 1.5-kilometre free-space link12,13. This advance in frequency ratio measurements lays the groundwork for future networks of mobile, airborne and remote optical clocks that will be used to test physical laws1, perform relativistic geodesy14 and substantially improve international timekeeping15.
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22
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Dix-Matthews BP, Schediwy SW, Gozzard DR, Savalle E, Esnault FX, Lévèque T, Gravestock C, D'Mello D, Karpathakis S, Tobar M, Wolf P. Point-to-point stabilized optical frequency transfer with active optics. Nat Commun 2021; 12:515. [PMID: 33483509 PMCID: PMC7822849 DOI: 10.1038/s41467-020-20591-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Accepted: 12/08/2020] [Indexed: 01/30/2023] Open
Abstract
Timescale comparison between optical atomic clocks over ground-to-space and terrestrial free-space laser links will have enormous benefits for fundamental and applied sciences. However, atmospheric turbulence creates phase noise and beam wander that degrade the measurement precision. Here we report on phase-stabilized optical frequency transfer over a 265 m horizontal point-to-point free-space link between optical terminals with active tip-tilt mirrors to suppress beam wander, in a compact, human-portable set-up. A phase-stabilized 715 m underground optical fiber link between the two terminals is used to measure the performance of the free-space link. The active optical terminals enable continuous, cycle-slip free, coherent transmission over periods longer than an hour. In this work, we achieve residual instabilities of 2.7 × 10-6 rad2 Hz-1 at 1 Hz in phase, and 1.6 × 10-19 at 40 s of integration in fractional frequency; this performance surpasses the best optical atomic clocks, ensuring clock-limited frequency comparison over turbulent free-space links.
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Affiliation(s)
- Benjamin P Dix-Matthews
- International Centre for Radio Astronomy Research, The University of Western Australia, Perth, Australia.
- Australian Research Council Centre of Excellence for Engineered Quantum Systems, The University of Western Australia, Perth, Australia.
| | - Sascha W Schediwy
- International Centre for Radio Astronomy Research, The University of Western Australia, Perth, Australia
- Australian Research Council Centre of Excellence for Engineered Quantum Systems, The University of Western Australia, Perth, Australia
| | - David R Gozzard
- International Centre for Radio Astronomy Research, The University of Western Australia, Perth, Australia
- Australian Research Council Centre of Excellence for Engineered Quantum Systems, The University of Western Australia, Perth, Australia
| | - Etienne Savalle
- SYRTE, Observatoire de Paris, Université PSL, CNRS, Sorbonne Université, LNE, Paris, France
| | | | - Thomas Lévèque
- Centre National d'Études Spatiales (CNES), Toulouse, France
| | - Charles Gravestock
- International Centre for Radio Astronomy Research, The University of Western Australia, Perth, Australia
| | - Darlene D'Mello
- International Centre for Radio Astronomy Research, The University of Western Australia, Perth, Australia
| | - Skevos Karpathakis
- International Centre for Radio Astronomy Research, The University of Western Australia, Perth, Australia
| | - Michael Tobar
- Australian Research Council Centre of Excellence for Engineered Quantum Systems, The University of Western Australia, Perth, Australia
| | - Peter Wolf
- SYRTE, Observatoire de Paris, Université PSL, CNRS, Sorbonne Université, LNE, Paris, France
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23
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Lange R, Huntemann N, Rahm JM, Sanner C, Shao H, Lipphardt B, Tamm C, Weyers S, Peik E. Improved Limits for Violations of Local Position Invariance from Atomic Clock Comparisons. PHYSICAL REVIEW LETTERS 2021; 126:011102. [PMID: 33480794 DOI: 10.1103/physrevlett.126.011102] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Revised: 11/23/2020] [Accepted: 12/15/2020] [Indexed: 06/12/2023]
Abstract
We compare two optical clocks based on the ^{2}S_{1/2}(F=0)→^{2}D_{3/2}(F=2) electric quadrupole (E2) and the ^{2}S_{1/2}(F=0)→^{2}F_{7/2}(F=3) electric octupole (E3) transition of ^{171}Yb^{+} and measure the frequency ratio ν_{E3}/ν_{E2}=0.932829404530965376(32), improving upon previous measurements by an order of magnitude. Using two caesium fountain clocks, we find ν_{E3}=642121496772645.10(8) Hz, the most accurate determination of an optical transition frequency to date. Repeated measurements of both quantities over several years are analyzed for potential violations of local position invariance. We improve by factors of about 20 and 2 the limits for fractional temporal variations of the fine structure constant α to 1.0(1.1)×10^{-18}/yr and of the proton-to-electron mass ratio μ to -8(36)×10^{-18}/yr. Using the annual variation of the Sun's gravitational potential at Earth Φ, we improve limits for a potential coupling of both constants to gravity, (c^{2}/α)(dα/dΦ)=14(11)×10^{-9} and (c^{2}/μ)(dμ/dΦ)=7(45)×10^{-8}.
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Affiliation(s)
- R Lange
- Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig, Germany
| | - N Huntemann
- Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig, Germany
| | - J M Rahm
- Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig, Germany
| | - C Sanner
- Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig, Germany
| | - H Shao
- Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig, Germany
| | - B Lipphardt
- Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig, Germany
| | - Chr Tamm
- Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig, Germany
| | - S Weyers
- Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig, Germany
| | - E Peik
- Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig, Germany
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24
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Liu H, Jäger SB, Yu X, Touzard S, Shankar A, Holland MJ, Nicholson TL. Rugged mHz-Linewidth Superradiant Laser Driven by a Hot Atomic Beam. PHYSICAL REVIEW LETTERS 2020; 125:253602. [PMID: 33416357 DOI: 10.1103/physrevlett.125.253602] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Accepted: 11/19/2020] [Indexed: 06/12/2023]
Abstract
We propose a new type of superradiant laser based on a hot atomic beam traversing an optical cavity. We show that the theoretical minimum linewidth and maximum power are competitive with the best ultracoherent clock lasers. Also, our system operates naturally in continuous wave mode, which has been elusive for superradiant lasers so far. Unlike existing ultracoherent lasers, our design is simple and rugged. This makes it a candidate for the first widely accessible ultracoherent laser, as well as the first to realize sought-after applications of ultracoherent lasers in challenging environments.
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Affiliation(s)
- Haonan Liu
- JILA, National Institute of Standards and Technology, and University of Colorado, Boulder, Colorado 80309-0440, USA
| | - Simon B Jäger
- JILA, National Institute of Standards and Technology, and University of Colorado, Boulder, Colorado 80309-0440, USA
| | - Xianquan Yu
- Centre for Quantum Technologies, Department of Physics, National University of Singapore, Singapore 117543
| | - Steven Touzard
- Centre for Quantum Technologies, Department of Physics, National University of Singapore, Singapore 117543
| | - Athreya Shankar
- JILA, National Institute of Standards and Technology, and University of Colorado, Boulder, Colorado 80309-0440, USA
| | - Murray J Holland
- JILA, National Institute of Standards and Technology, and University of Colorado, Boulder, Colorado 80309-0440, USA
| | - Travis L Nicholson
- Centre for Quantum Technologies, Department of Physics, National University of Singapore, Singapore 117543
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25
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Loh W, Stuart J, Reens D, Bruzewicz CD, Braje D, Chiaverini J, Juodawlkis PW, Sage JM, McConnell R. Operation of an optical atomic clock with a Brillouin laser subsystem. Nature 2020; 588:244-249. [PMID: 33299197 DOI: 10.1038/s41586-020-2981-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Accepted: 10/01/2020] [Indexed: 11/09/2022]
Abstract
Microwave atomic clocks have traditionally served as the 'gold standard' for precision measurements of time and frequency. However, over the past decade, optical atomic clocks1-6 have surpassed the precision of their microwave counterparts by two orders of magnitude or more. Extant optical clocks occupy volumes of more than one cubic metre, and it is a substantial challenge to enable these clocks to operate in field environments, which requires the ruggedization and miniaturization of the atomic reference and clock laser along with their supporting lasers and electronics4,7,8,9. In terms of the clock laser, prior laboratory demonstrations of optical clocks have relied on the exceptional performance gained through stabilization using bulk cavities, which unfortunately necessitates the use of vacuum and also renders the laser susceptible to vibration-induced noise. Here, using a stimulated Brillouin scattering laser subsystem that has a reduced cavity volume and operates without vacuum, we demonstrate a promising component of a portable optical atomic clock architecture. We interrogate a 88Sr+ ion with our stimulated Brillouin scattering laser and achieve a clock exhibiting short-term stability of 3.9 × 10-14 over one second-an improvement of an order of magnitude over state-of-the-art microwave clocks. This performance increase within a potentially portable system presents a compelling avenue for substantially improving existing technology, such as the global positioning system, and also for enabling the exploration of topics such as geodetic measurements of the Earth, searches for dark matter and investigations into possible long-term variations of fundamental physics constants10-12.
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Affiliation(s)
- William Loh
- Lincoln Laboratory, Massachusetts Institute of Technology, Lexington, MA, USA.
| | - Jules Stuart
- Lincoln Laboratory, Massachusetts Institute of Technology, Lexington, MA, USA.,Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - David Reens
- Lincoln Laboratory, Massachusetts Institute of Technology, Lexington, MA, USA
| | - Colin D Bruzewicz
- Lincoln Laboratory, Massachusetts Institute of Technology, Lexington, MA, USA
| | - Danielle Braje
- Lincoln Laboratory, Massachusetts Institute of Technology, Lexington, MA, USA
| | - John Chiaverini
- Lincoln Laboratory, Massachusetts Institute of Technology, Lexington, MA, USA
| | - Paul W Juodawlkis
- Lincoln Laboratory, Massachusetts Institute of Technology, Lexington, MA, USA
| | - Jeremy M Sage
- Lincoln Laboratory, Massachusetts Institute of Technology, Lexington, MA, USA.,Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Robert McConnell
- Lincoln Laboratory, Massachusetts Institute of Technology, Lexington, MA, USA
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26
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Kennedy CJ, Oelker E, Robinson JM, Bothwell T, Kedar D, Milner WR, Marti GE, Derevianko A, Ye J. Precision Metrology Meets Cosmology: Improved Constraints on Ultralight Dark Matter from Atom-Cavity Frequency Comparisons. PHYSICAL REVIEW LETTERS 2020; 125:201302. [PMID: 33258619 DOI: 10.1103/physrevlett.125.201302] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Accepted: 10/07/2020] [Indexed: 06/12/2023]
Abstract
We conduct frequency comparisons between a state-of-the-art strontium optical lattice clock, a cryogenic crystalline silicon cavity, and a hydrogen maser to set new bounds on the coupling of ultralight dark matter to standard model particles and fields in the mass range of 10^{-16}-10^{-21} eV. The key advantage of this two-part ratio comparison is the differential sensitivity to time variation of both the fine-structure constant and the electron mass, achieving a substantially improved limit on the moduli of ultralight dark matter, particularly at higher masses than typical atomic spectroscopic results. Furthermore, we demonstrate an extension of the search range to even higher masses by use of dynamical decoupling techniques. These results highlight the importance of using the best-performing atomic clocks for fundamental physics applications, as all-optical timescales are increasingly integrated with, and will eventually supplant, existing microwave timescales.
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Affiliation(s)
- Colin J Kennedy
- JILA, National Institute of Standards and Technology and University of Colorado, Boulder, Colorado 80309-0440, USA
| | - Eric Oelker
- JILA, National Institute of Standards and Technology and University of Colorado, Boulder, Colorado 80309-0440, USA
| | - John M Robinson
- JILA, National Institute of Standards and Technology and University of Colorado, Boulder, Colorado 80309-0440, USA
| | - Tobias Bothwell
- JILA, National Institute of Standards and Technology and University of Colorado, Boulder, Colorado 80309-0440, USA
| | - Dhruv Kedar
- JILA, National Institute of Standards and Technology and University of Colorado, Boulder, Colorado 80309-0440, USA
| | - William R Milner
- JILA, National Institute of Standards and Technology and University of Colorado, Boulder, Colorado 80309-0440, USA
| | - G Edward Marti
- JILA, National Institute of Standards and Technology and University of Colorado, Boulder, Colorado 80309-0440, USA
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, California 94305, United States
| | - Andrei Derevianko
- Department of Physics, University of Nevada, Reno, Nevada 89557, USA
| | - Jun Ye
- JILA, National Institute of Standards and Technology and University of Colorado, Boulder, Colorado 80309-0440, USA
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27
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Ohtsubo N, Li Y, Nemitz N, Hachisu H, Matsubara K, Ido T, Hayasaka K. Frequency ratio of an 115In + ion clock and a 87Sr optical lattice clock. OPTICS LETTERS 2020; 45:5950-5953. [PMID: 33137047 DOI: 10.1364/ol.404940] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Accepted: 09/23/2020] [Indexed: 06/11/2023]
Abstract
We report on the first, to the best of our knowledge, frequency ratio measurement of an 115In+ singleion clock and a 87Sr optical lattice clock. A hydrogen maser serves as a flywheel oscillator to measure the ratio by independent optical combs. From 89,000 s of measurement time, the frequency ratio fIn/fSr is determined to be 2.952 748 749 874 863 3(23) with 7.7×10-16 relative uncertainty. The measurement creates a new connection in the network of frequency ratios of optical clocks.
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28
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Hansmann AK, Berger R. Variation of the Fine-Structure Constant in Model Systems for Singlet Fission. J Phys Chem A 2020; 124:6682-6687. [DOI: 10.1021/acs.jpca.0c04685] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Anna-Katharina Hansmann
- Fachbereich Chemie, Philipps-Universität Marburg, Hans-Meerwein-Straße 4, 35032 Marburg, Germany
| | - Robert Berger
- Fachbereich Chemie, Philipps-Universität Marburg, Hans-Meerwein-Straße 4, 35032 Marburg, Germany
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29
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Diddams SA, Vahala K, Udem T. Optical frequency combs: Coherently uniting the electromagnetic spectrum. Science 2020; 369:369/6501/eaay3676. [PMID: 32675346 DOI: 10.1126/science.aay3676] [Citation(s) in RCA: 98] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Optical frequency combs were introduced around 20 years ago as a laser technology that could synthesize and count the ultrafast rate of the oscillating cycles of light. Functioning in a manner analogous to a clockwork of gears, the frequency comb phase-coherently upconverts a radio frequency signal by a factor of [Formula: see text] to provide a vast array of evenly spaced optical frequencies, which is the comb for which the device is named. It also divides an optical frequency down to a radio frequency, or translates its phase to any other optical frequency across hundreds of terahertz of bandwidth. We review the historical backdrop against which this powerful tool for coherently uniting the electromagnetic spectrum developed. Advances in frequency comb functionality, physical implementation, and application are also described.
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Affiliation(s)
- Scott A Diddams
- Time and Frequency Division, National Institute of Standards and Technology, Boulder, CO, USA. .,Department of Physics, University of Colorado, Boulder, CO, USA
| | - Kerry Vahala
- T. J. Watson Laboratory of Applied Physics, California Institute of Technology, Pasadena, CA, USA.
| | - Thomas Udem
- Max-Planck-Institut für Quantenoptik, Garching, Germany.
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30
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Nakamura T, Davila-Rodriguez J, Leopardi H, Sherman JA, Fortier TM, Xie X, Campbell JC, McGrew WF, Zhang X, Hassan YS, Nicolodi D, Beloy K, Ludlow AD, Diddams SA, Quinlan F. Coherent optical clock down-conversion for microwave frequencies with 10 -18 instability. Science 2020; 368:889-892. [PMID: 32439794 DOI: 10.1126/science.abb2473] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Accepted: 04/17/2020] [Indexed: 11/02/2022]
Abstract
Optical atomic clocks are poised to redefine the Système International (SI) second, thanks to stability and accuracy more than 100 times better than the current microwave atomic clock standard. However, the best optical clocks have not seen their performance transferred to the electronic domain, where radar, navigation, communications, and fundamental research rely on less stable microwave sources. By comparing two independent optical-to-electronic signal generators, we demonstrate a 10-gigahertz microwave signal with phase that exactly tracks that of the optical clock phase from which it is derived, yielding an absolute fractional frequency instability of 1 × 10-18 in the electronic domain. Such faithful reproduction of the optical clock phase expands the opportunities for optical clocks both technologically and scientifically for time dissemination, navigation, and long-baseline interferometric imaging.
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Affiliation(s)
- Takuma Nakamura
- Time and Frequency Division, National Institute of Standards and Technology, 325 Broadway, Boulder, CO 80305, USA. .,Department of Physics, University of Colorado Boulder, 440 UCB, Boulder, CO 80309, USA
| | - Josue Davila-Rodriguez
- Time and Frequency Division, National Institute of Standards and Technology, 325 Broadway, Boulder, CO 80305, USA
| | - Holly Leopardi
- Time and Frequency Division, National Institute of Standards and Technology, 325 Broadway, Boulder, CO 80305, USA.,Department of Physics, University of Colorado Boulder, 440 UCB, Boulder, CO 80309, USA
| | - Jeff A Sherman
- Time and Frequency Division, National Institute of Standards and Technology, 325 Broadway, Boulder, CO 80305, USA
| | - Tara M Fortier
- Time and Frequency Division, National Institute of Standards and Technology, 325 Broadway, Boulder, CO 80305, USA.,Department of Physics, University of Colorado Boulder, 440 UCB, Boulder, CO 80309, USA
| | - Xiaojun Xie
- Department of Electrical and Computer Engineering, University of Virginia, Charlottesville, VA 22904, USA
| | - Joe C Campbell
- Department of Electrical and Computer Engineering, University of Virginia, Charlottesville, VA 22904, USA
| | - William F McGrew
- Time and Frequency Division, National Institute of Standards and Technology, 325 Broadway, Boulder, CO 80305, USA.,Department of Physics, University of Colorado Boulder, 440 UCB, Boulder, CO 80309, USA
| | - Xiaogang Zhang
- Time and Frequency Division, National Institute of Standards and Technology, 325 Broadway, Boulder, CO 80305, USA.,Department of Physics, University of Colorado Boulder, 440 UCB, Boulder, CO 80309, USA
| | - Youssef S Hassan
- Time and Frequency Division, National Institute of Standards and Technology, 325 Broadway, Boulder, CO 80305, USA.,Department of Physics, University of Colorado Boulder, 440 UCB, Boulder, CO 80309, USA
| | - Daniele Nicolodi
- Time and Frequency Division, National Institute of Standards and Technology, 325 Broadway, Boulder, CO 80305, USA.,Department of Physics, University of Colorado Boulder, 440 UCB, Boulder, CO 80309, USA
| | - Kyle Beloy
- Time and Frequency Division, National Institute of Standards and Technology, 325 Broadway, Boulder, CO 80305, USA
| | - Andrew D Ludlow
- Time and Frequency Division, National Institute of Standards and Technology, 325 Broadway, Boulder, CO 80305, USA.,Department of Physics, University of Colorado Boulder, 440 UCB, Boulder, CO 80309, USA
| | - Scott A Diddams
- Time and Frequency Division, National Institute of Standards and Technology, 325 Broadway, Boulder, CO 80305, USA.,Department of Physics, University of Colorado Boulder, 440 UCB, Boulder, CO 80309, USA
| | - Franklyn Quinlan
- Time and Frequency Division, National Institute of Standards and Technology, 325 Broadway, Boulder, CO 80305, USA. .,Department of Physics, University of Colorado Boulder, 440 UCB, Boulder, CO 80309, USA
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31
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Ohmae N, Bregolin F, Nemitz N, Katori H. Direct measurement of the frequency ratio for Hg and Yb optical lattice clocks and closure of the Hg/Yb/Sr loop. OPTICS EXPRESS 2020; 28:15112-15121. [PMID: 32403544 DOI: 10.1364/oe.391602] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Accepted: 03/30/2020] [Indexed: 06/11/2023]
Abstract
We performed the first direct measurement of the frequency ratio between a mercury (199Hg) and an ytterbium (171Yb) optical lattice clock to find νHg/νYb = 2.177 473 194 134 565 07(19) with the fractional uncertainty of 8.8 × 10-17. The ratio is in excellent agreement with expectations from the ratios νHg/νSr and νYb/νSr obtained previously in comparisons against a strontium (87Sr) optical lattice clock. The completed closure (νHg/νYb)(νYb/νSr)(νSr/νHg) - 1 = 0.4(1.3) × 10-16 tests the frequency reproducibility of the optical lattice clocks beyond what is achievable in comparison against the current realization of the second in the International System of Units (SI).
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32
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Wang S, Cao J, Yuan J, Liu D, Shu H, Huang X. Integrated multiple wavelength stabilization on a multi-channel cavity for a transportable optical clock. OPTICS EXPRESS 2020; 28:11852-11860. [PMID: 32403687 DOI: 10.1364/oe.383115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Accepted: 03/30/2020] [Indexed: 06/11/2023]
Abstract
We present a simple, compact, and efficient scheme for integrated multiple wavelength stabilization and continuous operation of a transportable 40Ca+ optical clock using a multi-channel cavity. The fractional frequency instability of 729 nm clock laser is ∼ 1.5 ×10-15 at 10 s with an approximate linewidth of 1 Hz. Meanwhile, frequency fluctuations of all the other lasers are less than ± 330 kHz/day. The one-day stability of this clock is measured as ∼ 5 ×10-17 through 72 h continuous operation. This scheme is potentially useful for the realization of next-generation transportable optical clocks and other metrological systems.
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33
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Hees A, Do T, Roberts BM, Ghez AM, Nishiyama S, Bentley RO, Gautam AK, Jia S, Kara T, Lu JR, Saida H, Sakai S, Takahashi M, Takamori Y. Search for a Variation of the Fine Structure Constant around the Supermassive Black Hole in Our Galactic Center. PHYSICAL REVIEW LETTERS 2020; 124:081101. [PMID: 32167338 DOI: 10.1103/physrevlett.124.081101] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2019] [Accepted: 01/23/2020] [Indexed: 06/10/2023]
Abstract
Searching for space-time variations of the constants of Nature is a promising way to search for new physics beyond general relativity and the standard model motivated by unification theories and models of dark matter and dark energy. We propose a new way to search for a variation of the fine-structure constant using measurements of late-type evolved giant stars from the S star cluster orbiting the supermassive black hole in our Galactic Center. A measurement of the difference between distinct absorption lines (with different sensitivity to the fine structure constant) from a star leads to a direct estimate of a variation of the fine structure constant between the star's location and Earth. Using spectroscopic measurements of five stars, we obtain a constraint on the relative variation of the fine structure constant below 10^{-5}. This is the first time a varying constant of nature is searched for around a black hole and in a high gravitational potential. This analysis shows new ways the monitoring of stars in the Galactic Center can be used to probe fundamental physics.
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Affiliation(s)
- A Hees
- SYRTE, Observatoire de Paris, Université PSL, CNRS, Sorbonne Université, LNE, 61 avenue de l'Observatoire 75014 Paris, France
| | - T Do
- Department of Physics and Astronomy, University of California, Los Angeles, California 90095, USA
| | - B M Roberts
- SYRTE, Observatoire de Paris, Université PSL, CNRS, Sorbonne Université, LNE, 61 avenue de l'Observatoire 75014 Paris, France
- School of Mathematics and Physics, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - A M Ghez
- Department of Physics and Astronomy, University of California, Los Angeles, California 90095, USA
| | - S Nishiyama
- Miyagi University of Education, 149 Aramaki-aza-aoba, Aoba-ku, Sendai, Miyagi 980-0845, Japan
| | - R O Bentley
- Department of Physics and Astronomy, University of California, Los Angeles, California 90095, USA
| | - A K Gautam
- Department of Physics and Astronomy, University of California, Los Angeles, California 90095, USA
| | - S Jia
- Astronomy Department, University of California, Berkeley, California 94720, USA
| | - T Kara
- Miyagi University of Education, 149 Aramaki-aza-aoba, Aoba-ku, Sendai, Miyagi 980-0845, Japan
| | - J R Lu
- Astronomy Department, University of California, Berkeley, California 94720, USA
| | - H Saida
- Daido University, 10-3 Takiharu-cho, Minami-ku, Nagoya, Aichi 457-8530, Japan
| | - S Sakai
- Department of Physics and Astronomy, University of California, Los Angeles, California 90095, USA
| | - M Takahashi
- Aichi University of Education, 1 Hirosawa, Igaya-cho, Kariya, Aichi 448-8542, Japan
| | - Y Takamori
- National Institute of Technology, Wakayama College, 77 Noshima, Nada-cho, Gobo, Wakayama 644-0023, Japan
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34
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Measurement of the variation of electron-to-proton mass ratio using ultracold molecules produced from laser-cooled atoms. Nat Commun 2019; 10:3771. [PMID: 31434889 PMCID: PMC6704166 DOI: 10.1038/s41467-019-11761-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Accepted: 08/02/2019] [Indexed: 11/16/2022] Open
Abstract
Experimental techniques to manipulate cold molecules have seen great development in recent years. The precision measurements of cold molecules are expected to give insights into fundamental physics. Here we use a rovibrationally pure sample of ultracold KRb molecules to improve the measurement on the stability of electron-to-proton mass ratio \documentclass[12pt]{minimal}
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\begin{document}$$\left( {\mu = \frac{{m_{\mathrm{e}}}}{{M_{\mathrm{p}}}}} \right)$$\end{document}μ=meMp. The measurement is based upon a large sensitivity coefficient of the molecular spectroscopy, which utilizes a transition between a nearly degenerate pair of vibrational levels each associated with a different electronic potential. Observed limit on temporal variation of μ is \documentclass[12pt]{minimal}
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\begin{document}$$\frac{1}{\mu }\frac{{d\mu }}{{dt}} = (0.30 \pm 1.0) \times 10^{ - 14} \, {\mathrm{year}}^{ - 1}$$\end{document}1μdμdt=(0.30±1.0)×10-14year-1, which is better by a factor of five compared with the most stringent laboratory molecular limits to date. Further improvements should be straightforward, because our measurement was only limited by statistical errors. Ultracold molecules are suitable platforms for precision measurements due to their internal degrees of freedom. Here the authors derive a limit on the variation of the electron-to-proton mass ratio by using the spectroscopy of ultracold KRb molecules.
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35
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Shaniv R, Akerman N, Manovitz T, Shapira Y, Ozeri R. Quadrupole Shift Cancellation Using Dynamic Decoupling. PHYSICAL REVIEW LETTERS 2019; 122:223204. [PMID: 31283290 DOI: 10.1103/physrevlett.122.223204] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Indexed: 06/09/2023]
Abstract
We present a method that uses radio-frequency pulses to cancel the quadrupole shift in optical clock transitions. Quadrupole shifts are an inherent inhomogeneous broadening mechanism in trapped ion crystals and impose one of the limitations forcing current optical ion clocks to work with a single probe ion. Canceling this shift, at each interrogation cycle of the ion frequency, reduces the complexity in using N>1 ions in clocks, thus allowing for a reduction of the instability in the clock frequency by sqrt[N] according to the standard quantum limit. Our sequence relies on the tensorial nature of the quadrupole shift, and thus also cancels other tensorial shifts, such as the tensor ac stark shift. We experimentally demonstrate our sequence on three and seven ^{88}Sr^{+} ions trapped in a linear Paul trap, using correlation spectroscopy. We show a reduction of the quadrupole shift difference between ions to the ≈10 mHz level where other shifts, such as the relativistic second-order Doppler shift, are expected to limit our spectral resolution. In addition, we show that using radio-frequency dynamic decoupling we can also cancel the effect of first-order Zeeman shifts.
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Affiliation(s)
- Ravid Shaniv
- Department of Physics of Complex Systems, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Nitzan Akerman
- Department of Physics of Complex Systems, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Tom Manovitz
- Department of Physics of Complex Systems, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Yotam Shapira
- Department of Physics of Complex Systems, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Roee Ozeri
- Department of Physics of Complex Systems, Weizmann Institute of Science, Rehovot 7610001, Israel
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36
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Chae E, Nakashima K, Ikeda T, Sugiyama K, Yoshioka K. Direct phase-locking of a Ti:Sapphire optical frequency comb to a remote optical frequency standard. OPTICS EXPRESS 2019; 27:15649-15661. [PMID: 31163759 DOI: 10.1364/oe.27.015649] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Accepted: 05/06/2019] [Indexed: 06/09/2023]
Abstract
We report on an ultralow noise optical frequency transfer from a remotely located Sr optical lattice clock laser to a Ti:Sapphire optical frequency comb through telecom-wavelength optical fiber networks. The inherent narrow linewidth of the Ti:Sapphire optical frequency comb eliminates the need for a local reference high-finesse cavity. The relative fractional frequency instability of the optical frequency comb with respect to the remote optical reference was 6.7(1) × 10-18 at 1 s and 1.05(3) × 10-19 at 1,000 s including a 2.9 km-long fiber network. This ensured the optical frequency comb had the same precision as the optical standard. Our result paves the way for ultrahigh-precision spectroscopy and conversion of the highly precise optical frequency to radio frequencies in a simpler setup.
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37
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Liehl A, Sulzer P, Fehrenbacher D, Rybka T, Seletskiy DV, Leitenstorfer A. Deterministic Nonlinear Transformations of Phase Noise in Quantum-Limited Frequency Combs. PHYSICAL REVIEW LETTERS 2019; 122:203902. [PMID: 31172766 DOI: 10.1103/physrevlett.122.203902] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Indexed: 06/09/2023]
Abstract
Optical phase noise of femtosecond lasers is analyzed over various steps of broadband nonlinear frequency conversion. The intrinsic phase jitter of our system originates from quantum statistics in the mode-locked oscillator. Supercontinuum generation by four-wave-mixing processes preserves a noise minimum at the optical carrier frequency. From there, a quadratic increase of the comb linewidth results with mutually anticorrelated phase fluctuations of both spectral wings. Passive phase locking by difference frequency generation strongly enhances the optical phase noise to a level equaling the carrier-envelope phase jitter of the fundamental comb. The same value results from quadratic extrapolation of the optical phase noise to radio frequencies. Our findings are consistent with a fully deterministic transformation of phase noise according to the elastic tape model.
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Affiliation(s)
- A Liehl
- Department of Physics and Center for Applied Photonics, University of Konstanz, D-78457 Konstanz, Germany
| | - P Sulzer
- Department of Physics and Center for Applied Photonics, University of Konstanz, D-78457 Konstanz, Germany
| | - D Fehrenbacher
- Department of Physics and Center for Applied Photonics, University of Konstanz, D-78457 Konstanz, Germany
| | - T Rybka
- Department of Physics and Center for Applied Photonics, University of Konstanz, D-78457 Konstanz, Germany
| | - D V Seletskiy
- Department of Physics and Center for Applied Photonics, University of Konstanz, D-78457 Konstanz, Germany
- Department of Engineering Physics, Polytechnique Montréal, Montréal, H3T 1J4, Canada
| | - A Leitenstorfer
- Department of Physics and Center for Applied Photonics, University of Konstanz, D-78457 Konstanz, Germany
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38
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Hannig S, Pelzer L, Scharnhorst N, Kramer J, Stepanova M, Xu ZT, Spethmann N, Leroux ID, Mehlstäubler TE, Schmidt PO. Towards a transportable aluminium ion quantum logic optical clock. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2019; 90:053204. [PMID: 31153262 DOI: 10.1063/1.5090583] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Accepted: 05/07/2019] [Indexed: 06/09/2023]
Abstract
With the advent of optical clocks featuring fractional frequency uncertainties on the order of 10-17 and below, new applications such as chronometric leveling with few-centimeter height resolution emerge. We are developing a transportable optical clock based on a single trapped aluminum ion, which is interrogated via quantum logic spectroscopy. We employ singly charged calcium as the logic ion for sympathetic cooling, state preparation, and readout. Here, we present a simple and compact physics and laser package for manipulation of 40Ca+. Important features are a segmented multilayer trap with separate loading and probing zones, a compact titanium vacuum chamber, a near-diffraction-limited imaging system with high numerical aperture based on a single biaspheric lens, and an all-in-fiber 40Ca+ repump laser system. We present preliminary estimates of the trap-induced frequency shifts on 27Al+, derived from measurements with a single calcium ion. The micromotion-induced second-order Doppler shift for 27Al+ has been determined to be δνEMMν=-0.4-0.3 +0.4×10-18 and the black-body radiation shift is δνBBR/ν = (-4.0 ± 0.4) × 10-18. Moreover, heating rates of 30 (7) quanta per second at trap frequencies of ωrad,Ca+ ≈ 2π × 2.5 MHz (ωax,Ca+ ≈ 2π × 1.5 MHz) in radial (axial) direction have been measured, enabling interrogation times of a few hundreds of milliseconds.
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Affiliation(s)
- S Hannig
- Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig, Germany
| | - L Pelzer
- Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig, Germany
| | - N Scharnhorst
- Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig, Germany
| | - J Kramer
- Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig, Germany
| | - M Stepanova
- Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig, Germany
| | - Z T Xu
- MOE Key Laboratory of Fundamental Physical Quantities Measurement, School of Physics, Huazhong University of Science and Technology, 430074 Wuhan, People's Republic of China
| | - N Spethmann
- Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig, Germany
| | - I D Leroux
- Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig, Germany
| | - T E Mehlstäubler
- Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig, Germany
| | - P O Schmidt
- Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig, Germany
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39
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Optical clock comparison for Lorentz symmetry testing. Nature 2019; 567:204-208. [DOI: 10.1038/s41586-019-0972-2] [Citation(s) in RCA: 88] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Accepted: 01/23/2019] [Indexed: 11/09/2022]
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40
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Hisai Y, Akamatsu D, Kobayashi T, Okubo S, Inaba H, Hosaka K, Yasuda M, Hong FL. Development of 8-branch Er:fiber frequency comb for Sr and Yb optical lattice clocks. OPTICS EXPRESS 2019; 27:6404-6414. [PMID: 30876226 DOI: 10.1364/oe.27.006404] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Accepted: 02/12/2019] [Indexed: 06/09/2023]
Abstract
We demonstrate an 8-branch Er:fiber frequency comb with seven application ports, which can be individually optimized for applications with different wavelengths. The beat between the comb and a cw laser has a signal-to-noise ratio exceeding 30 dB at a resolution bandwidth of 300 kHz. The 8-branch frequency comb is used to perform frequency locking for four repumping and lattice lasers, and the frequency measurement of two clock lasers of strontium and ytterbium optical lattice clocks. We have achieved reliable optical lattice clock operation, thanks to the stable frequency locking and measurement obtained by using the 8-branch frequency comb. The developed frequency comb is a powerful experimental tool for various applications, including not only optical lattice clocks, but also research on quantum optics that use many frequency-stabilized lasers.
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41
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Mulholland S, Klein HA, Barwood GP, Donnellan S, Nisbet-Jones PBR, Huang G, Walsh G, Baird PEG, Gill P. Compact laser system for a laser-cooled ytterbium ion microwave frequency standard. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2019; 90:033105. [PMID: 30927817 DOI: 10.1063/1.5082703] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2018] [Accepted: 02/26/2019] [Indexed: 06/09/2023]
Abstract
The development of a transportable microwave frequency standard based on the ground-state transition of 171Yb+ at ∼12.6 GHz requires a compact laser system for cooling the ions, clearing out of long-lived states and also for photoionisation. In this paper, we describe the development of a suitable compact laser system based on a 6U height rack-mounted arrangement with overall dimensions 260 × 194 × 335 mm. Laser outputs at 369 nm (for cooling), 399 nm (photoionisation), 935 nm (repumping), and 760 nm (state clearout) are combined in a fiber arrangement for delivery to our linear ion trap and we demonstrate this system by cooling of 171Yb+ ions. Additionally, we demonstrate that the lasers at 935 nm and 760 nm are close in frequency to water vapor and oxygen absorption lines, respectively; specifically, at 760 nm, we show that one 171Yb+ transition is within the pressure broadened profile of an oxygen line. These molecular transitions form convenient wavelength references for the stabilization of lasers for a 171Yb+ frequency standard.
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Affiliation(s)
- S Mulholland
- National Physical Laboratory, Teddington TW11 0LW, United Kingdom
| | - H A Klein
- National Physical Laboratory, Teddington TW11 0LW, United Kingdom
| | - G P Barwood
- National Physical Laboratory, Teddington TW11 0LW, United Kingdom
| | - S Donnellan
- National Physical Laboratory, Teddington TW11 0LW, United Kingdom
| | | | - G Huang
- National Physical Laboratory, Teddington TW11 0LW, United Kingdom
| | - G Walsh
- National Physical Laboratory, Teddington TW11 0LW, United Kingdom
| | - P E G Baird
- Clarendon Laboratory, University of Oxford, Oxford, United Kingdom
| | - P Gill
- National Physical Laboratory, Teddington TW11 0LW, United Kingdom
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42
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Arias A, Lochead G, Wintermantel TM, Helmrich S, Whitlock S. Realization of a Rydberg-Dressed Ramsey Interferometer and Electrometer. PHYSICAL REVIEW LETTERS 2019; 122:053601. [PMID: 30822025 DOI: 10.1103/physrevlett.122.053601] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Revised: 12/14/2018] [Indexed: 06/09/2023]
Abstract
We present the experimental realization and characterization of a Ramsey interferometer based on optically trapped ultracold potassium atoms, where one state is continuously coupled by an off-resonant laser field to a highly excited Rydberg state. We show that the observed interference signals can be used to precisely measure the Rydberg atom-light coupling strength as well as the population and coherence decay rates of the Rydberg-dressed states with subkilohertz accuracy and for Rydberg state fractions as small as one part in 10^{6}. We also demonstrate an application for measuring small, static electric fields with high sensitivity. This provides the means to combine the outstanding coherence properties of Ramsey interferometers based on atomic ground states with a controllable coupling to strongly interacting states, thus expanding the number of systems suitable for metrological applications and many-body physics studies.
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Affiliation(s)
- A Arias
- Physikalisches Institut, Universität Heidelberg, Im Neuenheimer Feld 226, 69120 Heidelberg, Germany
- IPCMS (UMR 7504) and ISIS (UMR 7006), University of Strasbourg and CNRS, 67000 Strasbourg, France
| | - G Lochead
- Physikalisches Institut, Universität Heidelberg, Im Neuenheimer Feld 226, 69120 Heidelberg, Germany
- IPCMS (UMR 7504) and ISIS (UMR 7006), University of Strasbourg and CNRS, 67000 Strasbourg, France
| | - T M Wintermantel
- Physikalisches Institut, Universität Heidelberg, Im Neuenheimer Feld 226, 69120 Heidelberg, Germany
- IPCMS (UMR 7504) and ISIS (UMR 7006), University of Strasbourg and CNRS, 67000 Strasbourg, France
| | - S Helmrich
- Physikalisches Institut, Universität Heidelberg, Im Neuenheimer Feld 226, 69120 Heidelberg, Germany
| | - S Whitlock
- Physikalisches Institut, Universität Heidelberg, Im Neuenheimer Feld 226, 69120 Heidelberg, Germany
- IPCMS (UMR 7504) and ISIS (UMR 7006), University of Strasbourg and CNRS, 67000 Strasbourg, France
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Schwarz R, Dörscher S, Al-Masoudi A, Vogt S, Li Y, Lisdat C. A compact and robust cooling laser system for an optical strontium lattice clock. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2019; 90:023109. [PMID: 30831754 DOI: 10.1063/1.5063552] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Accepted: 02/01/2019] [Indexed: 06/09/2023]
Abstract
We present a simple and robust laser system for two-color, narrow-line cooling on the 87Sr (5s2)1S0 → (5s5p)3P1 transition. Two hyperfine lines of this transition are addressed simultaneously with light from a single laser source, using sidebands created by an electro-optical phase modulator. A tapered amplifier system provides laser powers up to 90 mW. We show that amplification does not affect the phase modulation of the laser. This compact and robust laser system offers excellent reliability. Therefore, it is especially well suited for transportable and spaceborne optical clocks. The design offers the potential to be miniaturized into a fully integrated package.
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Affiliation(s)
- Roman Schwarz
- Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig, Germany
| | - Sören Dörscher
- Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig, Germany
| | - Ali Al-Masoudi
- Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig, Germany
| | - Stefan Vogt
- Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig, Germany
| | - Ye Li
- Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig, Germany
| | - Christian Lisdat
- Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig, Germany
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Berengut JC. Resonant Electronic-Bridge Excitation of the ^{235}U Nuclear Transition in Ions with Chaotic Spectra. PHYSICAL REVIEW LETTERS 2018; 121:253002. [PMID: 30608803 DOI: 10.1103/physrevlett.121.253002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2018] [Revised: 11/02/2018] [Indexed: 06/09/2023]
Abstract
Electronic-bridge excitation of the 76 eV nuclear isomeric state in ^{235}U is shown to be strongly enhanced in the U^{7+} ion, potentially enabling laser excitation of this nucleus. This is because the electronic spectrum has a very high level density near the nuclear transition energy that ensures the resonance condition is fulfilled. We present a quantum statistical theory based on many-body quantum chaos to demonstrate that typical values for the electronic factor increase the probability of electronic bridge in ^{235}U^{7+} by many orders of magnitude. We also extract the nuclear matrix element by considering internal conversion from neutral uranium. The final electronic-bridge rate is comparable to the rate of the Yb^{+} octupole transition currently used in precision spectroscopy.
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Affiliation(s)
- J C Berengut
- School of Physics, University of New South Wales, New South Wales 2052, Australia and Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany
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Kobayashi T, Akamatsu D, Hisai Y, Tanabe T, Inaba H, Suzuyama T, Hong FL, Hosaka K, Yasuda M. Uncertainty Evaluation of an 171Yb Optical Lattice Clock at NMIJ. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2018; 65:2449-2458. [PMID: 30235125 DOI: 10.1109/tuffc.2018.2870937] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
We report an uncertainty evaluation of an 171Yb optical lattice clock with a total fractional uncertainty of 3.6×10-16 , which is mainly limited by the lattice-induced light shift and the blackbody radiation shift. Our evaluation of the lattice-induced light shift, the density shift, and the second-order Zeeman shift is based on an interleaved measurement where we measure the frequency shift using the alternating stabilization of a clock laser to the 6s2 1S0-6s6p 3P0 clock transition with two different experimental parameters. In the present evaluation, the uncertainties of two sensitivity coefficients for the lattice-induced hyperpolarizability shift d incorporated in a widely used light shift model by RIKEN and the second-order Zeeman shift aZ are improved compared with the uncertainties of previous coefficients. The hyperpolarizability coefficient d is determined by investigating the trap potential depth and the light shifts at the lattice frequencies near the two-photon transitions 6s6p3P0-6s8p3P0, 6s8p3P2, and 6s5f3F2. The obtained values are d=-1.1(4) μ Hz and aZ=-6.6(3) Hz/mT2. These improved coefficients should reduce the total systematic uncertainties of Yb lattice clocks at other institutes.
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Recent Advances Concerning the 87Sr Optical Lattice Clock at the National Time Service Center. APPLIED SCIENCES-BASEL 2018. [DOI: 10.3390/app8112194] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
We review recent experimental progress concerning the 87Sr optical lattice clock at the National Time Service Center in China. Hertz-level spectroscopy of the 87Sr clock transition for the optical lattice clock was performed, and closed-loop operation of the optical lattice clock was realized. A fractional frequency instability of 2.8 × 10−17 was attained for an averaging time of 2000 s. The Allan deviation is found to be 1.6 × 10−15/τ1/2 and is limited mainly by white-frequency-noise. The Landé g-factors of the (5s2)1S0 and (5s5p)3P0 states in 87Sr were measured experimentally; they are important for evaluating the clock’s Zeeman shifts. We also present recent work on the miniaturization of the strontium optical lattice clock for space applications.
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Abstract
Molecular overtone transitions provide optical frequency transitions sensitive to variation in the proton-to-electron mass ratio ( μ ≡ m p / m e ). However, robust molecular state preparation presents a challenge critical for achieving high precision. Here, we characterize infrared and optical-frequency broadband laser cooling schemes for TeH + , a species with multiple electronic transitions amenable to sustained laser control. Using rate equations to simulate laser cooling population dynamics, we estimate the fractional sensitivity to μ attainable using TeH + . We find that laser cooling of TeH + can lead to significant improvements on current μ variation limits.
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Mitaki M, Sugiyama K, Kitano M. Octave-spanning optical frequency comb based on a laser-diode pumped Kerr-lens mode-locked Yb:KYW laser for optical frequency measurement. APPLIED OPTICS 2018; 57:5150-5160. [PMID: 30117977 DOI: 10.1364/ao.57.005150] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Accepted: 05/24/2018] [Indexed: 06/08/2023]
Abstract
We developed an optical frequency comb based on a Yb:KYW laser. Soft-aperture Kerr-lens mode-locking at the cavity transverse-mode degeneration enabled us to generate 360 mW from a 750 mW pump laser diode. This resulted in spectral broadening over one octave using just a photonic crystal fiber. We achieved a free-running linewidth of 15 kHz in the carrier-envelope offset frequency by optimizing the cavity group delay dispersion, crystal position, and pump laser power, which led to a residual phase noise of 0.51 rad during phase-locking. We measured the frequency drift of a cavity-stabilized laser for a clock transition in Yb171+.
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Mehlstäubler TE, Grosche G, Lisdat C, Schmidt PO, Denker H. Atomic clocks for geodesy. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2018; 81:064401. [PMID: 29667603 DOI: 10.1088/1361-6633/aab409] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
We review experimental progress on optical atomic clocks and frequency transfer, and consider the prospects of using these technologies for geodetic measurements. Today, optical atomic frequency standards have reached relative frequency inaccuracies below 10-17, opening new fields of fundamental and applied research. The dependence of atomic frequencies on the gravitational potential makes atomic clocks ideal candidates for the search for deviations in the predictions of Einstein's general relativity, tests of modern unifying theories and the development of new gravity field sensors. In this review, we introduce the concepts of optical atomic clocks and present the status of international clock development and comparison. Besides further improvement in stability and accuracy of today's best clocks, a large effort is put into increasing the reliability and technological readiness for applications outside of specialized laboratories with compact, portable devices. With relative frequency uncertainties of 10-18, comparisons of optical frequency standards are foreseen to contribute together with satellite and terrestrial data to the precise determination of fundamental height reference systems in geodesy with a resolution at the cm-level. The long-term stability of atomic standards will deliver excellent long-term height references for geodetic measurements and for the modelling and understanding of our Earth.
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Affiliation(s)
- Tanja E Mehlstäubler
- Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig, Germany
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