1
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Hughes WJ, Doherty TH, Blackmore JA, Horak P, Goodwin JF. Mode mixing and losses in misaligned microcavities. OPTICS EXPRESS 2023; 31:32619-32636. [PMID: 37859061 DOI: 10.1364/oe.496981] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Accepted: 08/11/2023] [Indexed: 10/21/2023]
Abstract
We present a study on the optical losses of Fabry-Pérot cavities subject to realistic transverse mirror misalignment. We consider mirrors of the two most prevalent surface forms: idealised spherical depressions, and Gaussian profiles generated by laser ablation. We first describe the mode mixing phenomena seen in the spherical mirror case and compare to the frequently-used clipping model, observing close agreement in the predicted diffraction loss, but with the addition of protective mode mixing at transverse degeneracies. We then discuss the Gaussian mirror case, detailing how the varying surface curvature across the mirror leads to complex variations in round trip loss and mode profile. In light of the severe mode distortion and strongly elevated loss predicted for many cavity lengths and transverse alignments when using Gaussian mirrors, we suggest that the consequences of mirror surface profile are carefully considered when designing cavity experiments.
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2
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Liu Q, Liu W, Ziegler K, Chen F. Engineering of Zeno Dynamics in Integrated Photonics. PHYSICAL REVIEW LETTERS 2023; 130:103801. [PMID: 36962047 DOI: 10.1103/physrevlett.130.103801] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Revised: 11/06/2022] [Accepted: 02/15/2023] [Indexed: 06/18/2023]
Abstract
Frequent observations to a quantum system modify its coherent evolution through the Zeno effect and Zeno dynamics. Generally, the measurement process destroys the evolution environment of the monitored system, making repeated observations remain a challenge. Here, using the quantum analogy experiments, we realize and engineer the Zeno effect and Zeno dynamics in optical waveguide arrays, where the optical modes correspond to distinct quantum states, and the temporal evolution is mapped into the spatial propagation. We propose a new, extensible experimental strategy for realizing an optical analog of stroboscopic measurements, which are performed by the build-in, on-demand segmented waveguide portions. The weak-to-strong stroboscopic measurements are realized, where the monitored system undergoes a transition from free evolution to optical Zeno freezing. Setting the measurements in the strong regime, the optical Zeno effect and optical Zeno dynamics are successfully generated, and their relationship is demonstrated in optics. We then propose a novel quantum Zeno slicing approach, which allows us to dynamically engineer the Hilbert space of the monitored system. This generic approach is verified by generating a series of Zeno subspaces with different measurement projectors, based on the quantum-optical analogy. The complexity of light dynamics is largely increased, providing full control of the propagation via steering Zeno dynamics. Our results pave the way for manipulation of quantum states by harnessing Zeno dynamics in integrated photonics.
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Affiliation(s)
- Quancheng Liu
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China
- Department of Physics, Institute of Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat-Gan 52900, Israel
| | - Weijie Liu
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China
| | - Klaus Ziegler
- Institut für Physik, Universität Augsburg, D-86135 Augsburg, Germany
| | - Feng Chen
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China
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3
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Bayrakci V, Ozaydin F. Quantum Zeno repeaters. Sci Rep 2022; 12:15302. [PMID: 36097033 PMCID: PMC9468345 DOI: 10.1038/s41598-022-19170-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Accepted: 08/25/2022] [Indexed: 11/09/2022] Open
Abstract
Quantum repeaters pave the way for long-distance quantum communications and quantum Internet, and the idea of quantum repeaters is based on entanglement swapping which requires the implementation of controlled quantum gates. Frequently measuring a quantum system affects its dynamics which is known as the quantum Zeno effect (QZE). Beyond slowing down its evolution, QZE can be used to control the dynamics of a quantum system by introducing a carefully designed set of operations between measurements. Here, we propose an entanglement swapping protocol based on QZE, which achieves almost unit fidelity. Implementation of our protocol requires only simple frequent threshold measurements and single particle rotations. We extend the proposed entanglement swapping protocol to a series of repeater stations for constructing quantum Zeno repeaters which also achieve almost unit fidelity regardless of the number of repeaters. Requiring no controlled gates, our proposal reduces the quantum circuit complexity of quantum repeaters. Our work has potential to contribute to long distance quantum communications and quantum computing via quantum Zeno effect.
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Affiliation(s)
- Veysel Bayrakci
- Faculty of Engineering and Natural Sciences, Isik University, 34980, Sile, Istanbul, Türkiye.
| | - Fatih Ozaydin
- Institute for International Strategy, Tokyo International University, 1-13-1 Matoba-kita, Kawagoe, Saitama, 350-1197, Japan.,Department of Information Technologies, Isik University, 34980, Sile, Istanbul, Turkey.,CERN, 1211, Geneva 23, Switzerland
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4
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Nodurft IC, Shaw HC, Glasser RT, Kirby BT, Searles TA. Generation of polarization entanglement via the quantum Zeno effect. OPTICS EXPRESS 2022; 30:31971-31985. [PMID: 36242268 DOI: 10.1364/oe.464550] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Accepted: 08/03/2022] [Indexed: 06/16/2023]
Abstract
The quantum Zeno effect reveals that continuous observation of a quantum system can significantly alter its evolution. Here, we present a method for establishing polarization entanglement between two initially unentangled photons in coupled waveguides via the quantum Zeno effect. We support our analytical investigation with numerical simulations of the underlying Schrodinger equation describing the system. Further, we extend our technique to three coupled waveguides in a planar configuration and determine the parameters required to generate three-qubit W-states. In contrast to existing schemes based on a vacuum and single-photon encoding, the polarization encoding in our approach is compatible with quantum information protocols that remove photon loss through post-selection. Our findings offer a powerful quantum state engineering approach for photonic quantum information technologies.
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5
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Virzì S, Avella A, Piacentini F, Gramegna M, Opatrný T, Kofman AG, Kurizki G, Gherardini S, Caruso F, Degiovanni IP, Genovese M. Quantum Zeno and Anti-Zeno Probes of Noise Correlations in Photon Polarization. PHYSICAL REVIEW LETTERS 2022; 129:030401. [PMID: 35905356 DOI: 10.1103/physrevlett.129.030401] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Revised: 05/11/2022] [Accepted: 06/14/2022] [Indexed: 06/15/2023]
Abstract
We experimentally demonstrate, for the first time, noise diagnostics by repeated quantum measurements, establishing the ability of a single photon subjected to random polarization noise to diagnose non-Markovian temporal correlations of such a noise process. Both the noise spectrum and temporal correlations are diagnosed by probing the photon with frequent (partially) selective polarization measurements. We show that noise with positive temporal correlations corresponds to our single photon undergoing a dynamical regime enabled by the quantum Zeno effect (QZE), whereas noise characterized by negative (anti) correlations corresponds to regimes associated with the anti-Zeno effect (AZE). This is the first step toward a novel noise spectroscopy based on QZE and AZE in single-photon state probing able to extract information on the noise while protecting the probe state, a conceptual paradigm shift with respect to traditional interferometric measurements.
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Affiliation(s)
- Salvatore Virzì
- Istituto Nazionale di Ricerca Metrologica, Strada delle Cacce 91, 10135 Torino, Italy
| | - Alessio Avella
- Istituto Nazionale di Ricerca Metrologica, Strada delle Cacce 91, 10135 Torino, Italy
| | - Fabrizio Piacentini
- Istituto Nazionale di Ricerca Metrologica, Strada delle Cacce 91, 10135 Torino, Italy
| | - Marco Gramegna
- Istituto Nazionale di Ricerca Metrologica, Strada delle Cacce 91, 10135 Torino, Italy
| | - Tomáš Opatrný
- Department of Optics, Faculty of Science, Palacký University, 77146 Olomouc, Czech Republic
| | - Abraham G Kofman
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot 7610001, Israel and Department of Physics, Shanghai University, 200444 Shanghai, China
| | - Gershon Kurizki
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Stefano Gherardini
- Department of Physics and Astronomy and European Laboratory for Non-Linear Spectroscopy (LENS), University of Florence, via G. Sansone 1, 50019 Sesto Fiorentino, Italy and Istituto Nazionale di Ottica (CNR-INO), Area Science Park, Basovizza, I-34149 Trieste, Italy
| | - Filippo Caruso
- Department of Physics and Astronomy and European Laboratory for Non-Linear Spectroscopy (LENS), University of Florence, via G. Sansone 1, 50019 Sesto Fiorentino, Italy and Istituto Nazionale di Ottica (CNR-INO), Area Science Park, Basovizza, I-34149 Trieste, Italy
| | - Ivo Pietro Degiovanni
- Istituto Nazionale di Ricerca Metrologica, Strada delle Cacce 91, 10135 Torino, Italy and INFN, sezione di Torino, via P. Giuria 1, 10125 Torino, Italy
| | - Marco Genovese
- Istituto Nazionale di Ricerca Metrologica, Strada delle Cacce 91, 10135 Torino, Italy and INFN, sezione di Torino, via P. Giuria 1, 10125 Torino, Italy
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6
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Yang H, Li Z, Zhang S, Bohn JL, Cao L, Zhang S, Wang G, Xu H, Li Z. Channel Selection of Ultracold Atom-Molecule Scattering in Dynamic Magnetic Fields. PHYSICAL REVIEW LETTERS 2022; 129:013402. [PMID: 35841560 DOI: 10.1103/physrevlett.129.013402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 05/02/2022] [Accepted: 05/19/2022] [Indexed: 06/15/2023]
Abstract
We demonstrate that final states of ultracold molecules by scattering with atoms can be selectively produced using dynamic magnetic fields of multiple frequencies. We develop a multifrequency Floquet coupled channel method to study the channel selection by dynamic magnetic field control, which can be interpreted by a generalized quantum Zeno effect for the selected scattering channels. In particular, we use an atom-molecule spin-flip scattering to show that the transition to certain final states of the molecules in the inelastic scattering can be suppressed by engineered coupling between the Floquet states.
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Affiliation(s)
- Hanwei Yang
- State Key Laboratory for Mesoscopic Physics and Collaborative Innovation Center of Quantum Matter, School of Physics, Peking University, Beijing 100871, China
| | - Zunqi Li
- State Key Laboratory for Mesoscopic Physics and Collaborative Innovation Center of Quantum Matter, School of Physics, Peking University, Beijing 100871, China
| | - Songbin Zhang
- Department of Physics, Shaanxi Normal University, Xi'an 710119, China
| | - John L Bohn
- JILA, University of Colorado, Boulder, Colorado 80309, USA
| | - Lushuai Cao
- MOE Key Laboratory of Fundamental Physical Quantities Measurement & Hubei Key Laboratory of Gravitation and Quantum Physics, PGMF and School of Physics, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Shutao Zhang
- State Key Laboratory for Mesoscopic Physics and Collaborative Innovation Center of Quantum Matter, School of Physics, Peking University, Beijing 100871, China
| | - Gaoren Wang
- School of Physics, Dalian University of Technology, Dalian 116024, China
| | - Haitan Xu
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
- School of Physical Sciences, University of Science and Technology of China, Hefei 230026, China
| | - Zheng Li
- State Key Laboratory for Mesoscopic Physics and Collaborative Innovation Center of Quantum Matter, School of Physics, Peking University, Beijing 100871, China
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, China
- Peking University Yangtze Delta Institute of Optoelectronics, Nantong, China
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7
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Xu K, Zhang YR, Sun ZH, Li H, Song P, Xiang Z, Huang K, Li H, Shi YH, Chen CT, Song X, Zheng D, Nori F, Wang H, Fan H. Metrological Characterization of Non-Gaussian Entangled States of Superconducting Qubits. PHYSICAL REVIEW LETTERS 2022; 128:150501. [PMID: 35499907 DOI: 10.1103/physrevlett.128.150501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Accepted: 03/15/2022] [Indexed: 06/14/2023]
Abstract
Multipartite entangled states are significant resources for both quantum information processing and quantum metrology. In particular, non-Gaussian entangled states are predicted to achieve a higher sensitivity of precision measurements than Gaussian states. On the basis of metrological sensitivity, the conventional linear Ramsey squeezing parameter (RSP) efficiently characterizes the Gaussian entangled atomic states but fails for much wider classes of highly sensitive non-Gaussian states. These complex non-Gaussian entangled states can be classified by the nonlinear squeezing parameter (NLSP), as a generalization of the RSP with respect to nonlinear observables and identified via the Fisher information. However, the NLSP has never been measured experimentally. Using a 19-qubit programmable superconducting processor, we report the characterization of multiparticle entangled states generated during its nonlinear dynamics. First, selecting ten qubits, we measure the RSP and the NLSP by single-shot readouts of collective spin operators in several different directions. Then, by extracting the Fisher information of the time-evolved state of all 19 qubits, we observe a large metrological gain of 9.89_{-0.29}^{+0.28} dB over the standard quantum limit, indicating a high level of multiparticle entanglement for quantum-enhanced phase sensitivity. Benefiting from high-fidelity full controls and addressable single-shot readouts, the superconducting processor with interconnected qubits provides an ideal platform for engineering and benchmarking non-Gaussian entangled states that are useful for quantum-enhanced metrology.
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Affiliation(s)
- Kai Xu
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Yu-Ran Zhang
- Theoretical Quantum Physics Laboratory, RIKEN Cluster for Pioneering Research, Wako-shi, Saitama 351-0198, Japan
- RIKEN Center for Quantum Computing (RQC), Wako-shi, Saitama 351-0198, Japan
| | - Zheng-Hang Sun
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Hekang Li
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Pengtao Song
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Zhongcheng Xiang
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Kaixuan Huang
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Hao Li
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Yun-Hao Shi
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Chi-Tong Chen
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Xiaohui Song
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Dongning Zheng
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Franco Nori
- Theoretical Quantum Physics Laboratory, RIKEN Cluster for Pioneering Research, Wako-shi, Saitama 351-0198, Japan
- RIKEN Center for Quantum Computing (RQC), Wako-shi, Saitama 351-0198, Japan
- Physics Department, University of Michigan, Ann Arbor, Michigan 48109-1040, USA
| | - H Wang
- Interdisciplinary Center for Quantum Information, State Key Laboratory of Modern Optical Instrumentation, and Zhejiang Province Key Laboratory of Quantum Technology and Device, Department of Physics, Zhejiang University, Hangzhou 310027, China
| | - Heng Fan
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Beijing Academy of Quantum Information Sciences and CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100190, China
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8
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Rath A, Branciard C, Minguzzi A, Vermersch B. Quantum Fisher Information from Randomized Measurements. PHYSICAL REVIEW LETTERS 2021; 127:260501. [PMID: 35029488 DOI: 10.1103/physrevlett.127.260501] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Accepted: 11/17/2021] [Indexed: 06/14/2023]
Abstract
The quantum Fisher information (QFI) is a fundamental quantity of interest in many areas from quantum metrology to quantum information theory. It can in particular be used as a witness to establish the degree of multiparticle entanglement in quantum many-body systems. In this work, we use polynomials of the density matrix to construct monotonically increasing lower bounds that converge to the QFI. Using randomized measurements we propose a protocol to accurately estimate these lower bounds in state-of-the-art quantum technological platforms. We estimate the number of measurements needed to achieve a given accuracy and confidence level in the bounds, and present two examples of applications of the method in quantum systems made of coupled qubits and collective spins.
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Affiliation(s)
- Aniket Rath
- Université Grenoble Alpes, CNRS, LPMMC, 38000 Grenoble, France
| | - Cyril Branciard
- Université Grenoble Alpes, CNRS, Grenoble INP, Institut Néel, 38000 Grenoble, France
| | - Anna Minguzzi
- Université Grenoble Alpes, CNRS, LPMMC, 38000 Grenoble, France
| | - Benoît Vermersch
- Université Grenoble Alpes, CNRS, LPMMC, 38000 Grenoble, France
- Center for Quantum Physics, University of Innsbruck, Innsbruck A-6020, Austria
- Institute for Quantum Optics and Quantum Information of the Austrian Academy of Sciences, Innsbruck A-6020, Austria
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9
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Programmable interactions and emergent geometry in an array of atom clouds. Nature 2021; 600:630-635. [PMID: 34937894 DOI: 10.1038/s41586-021-04156-0] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Accepted: 10/15/2021] [Indexed: 11/08/2022]
Abstract
Interactions govern the flow of information and the formation of correlations between constituents of many-body quantum systems, dictating phases of matter found in nature and forms of entanglement generated in the laboratory. Typical interactions decay with distance and thus produce a network of connectivity governed by geometry-such as the crystalline structure of a material or the trapping sites of atoms in a quantum simulator1,2. However, many envisioned applications in quantum simulation and computation require more complex coupling graphs including non-local interactions, which feature in models of information scrambling in black holes3-6 and mappings of hard optimization problems onto frustrated classical magnets7-11. Here we describe the realization of programmable non-local interactions in an array of atomic ensembles within an optical cavity, in which photons carry information between atomic spins12-19. By programming the distance dependence of the interactions, we access effective geometries for which the dimensionality, topology and metric are entirely distinct from the physical geometry of the array. As examples, we engineer an antiferromagnetic triangular ladder, a Möbius strip with sign-changing interactions and a treelike geometry inspired by concepts of quantum gravity5,20-22. The tree graph constitutes a toy model of holographic duality21,22, in which the quantum system lies on the boundary of a higher-dimensional geometry that emerges from measured correlations23. Our work provides broader prospects for simulating frustrated magnets and topological phases24, investigating quantum optimization paradigms10,11,25,26 and engineering entangled resource states for sensing and computation27,28.
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10
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Ðorđević T, Samutpraphoot P, Ocola PL, Bernien H, Grinkemeyer B, Dimitrova I, Vuletić V, Lukin MD. Entanglement transport and a nanophotonic interface for atoms in optical tweezers. Science 2021; 373:1511-1514. [PMID: 34385353 DOI: 10.1126/science.abi9917] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The realization of an efficient quantum optical interface for multi-qubit systems is an outstanding challenge in science and engineering. Using two atoms in individually-controlled optical tweezers coupled to a nanofabricated photonic crystal cavity, we demonstrate entanglement generation, fast non-destructive readout, and full quantum control of atomic qubits. The entangled state is verified in free space after being transported away from the cavity by encoding the qubits into long-lived states and using dynamical decoupling. Our approach bridges quantum operations at an optical link and in free space by a coherent one-way transport, potentially enabling an integrated optical interface for atomic quantum processors.
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Affiliation(s)
- Tamara Ðorđević
- Department of Physics, Harvard University, Cambridge, MA 02138, USA.,Department of Physics, Harvard University, Cambridge, MA 02138, USA
| | - Polnop Samutpraphoot
- Department of Physics, Harvard University, Cambridge, MA 02138, USA.,Department of Physics, Harvard University, Cambridge, MA 02138, USA
| | - Paloma L Ocola
- Department of Physics, Harvard University, Cambridge, MA 02138, USA.,Department of Physics, Harvard University, Cambridge, MA 02138, USA
| | - Hannes Bernien
- Department of Physics and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.,Pritzker School of Molecular Engineering, University of Chicago, Chicago, IL 60637, USA
| | - Brandon Grinkemeyer
- Department of Physics, Harvard University, Cambridge, MA 02138, USA.,Department of Physics, Harvard University, Cambridge, MA 02138, USA
| | - Ivana Dimitrova
- Department of Physics, Harvard University, Cambridge, MA 02138, USA.,Department of Physics, Harvard University, Cambridge, MA 02138, USA
| | - Vladan Vuletić
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, IL 60637, USA.,Department of Physics and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Mikhail D Lukin
- Department of Physics, Harvard University, Cambridge, MA 02138, USA. .,Department of Physics, Harvard University, Cambridge, MA 02138, USA
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11
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Xu W, Venkatramani AV, Cantú SH, Šumarac T, Klüsener V, Lukin MD, Vuletić V. Fast Preparation and Detection of a Rydberg Qubit Using Atomic Ensembles. PHYSICAL REVIEW LETTERS 2021; 127:050501. [PMID: 34397223 DOI: 10.1103/physrevlett.127.050501] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Revised: 05/15/2021] [Accepted: 06/29/2021] [Indexed: 06/13/2023]
Abstract
We demonstrate a new approach for fast preparation, manipulation, and collective readout of an atomic Rydberg-state qubit. By making use of Rydberg blockade inside a small atomic ensemble, we prepare a single qubit within 3 μs with a success probability of F_{p}=0.93±0.02, rotate it, and read out its state in 6 μs with a single-shot fidelity of F_{d}=0.92±0.04. The ensemble-assisted detection is 10^{3} times faster than imaging of a single atom with the same optical resolution, and enables fast repeated nondestructive measurement. We observe qubit coherence times of 15 μs, much longer than the π rotation time of 90 ns. Potential applications ranging from faster quantum information processing in atom arrays to efficient implementation of quantum error correction are discussed.
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Affiliation(s)
- Wenchao Xu
- Department of Physics and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Aditya V Venkatramani
- Department of Physics and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Sergio H Cantú
- Department of Physics and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Tamara Šumarac
- Department of Physics and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Valentin Klüsener
- Department of Physics and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
- University of Erlangen-Nuremberg, Erlangen 91054, Germany
| | - Mikhail D Lukin
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Vladan Vuletić
- Department of Physics and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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12
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Groiseau C, Elliott AEJ, Masson SJ, Parkins S. Proposal for a Deterministic Single-Atom Source of Quasisuperradiant N-Photon Pulses. PHYSICAL REVIEW LETTERS 2021; 127:033602. [PMID: 34328761 DOI: 10.1103/physrevlett.127.033602] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Accepted: 05/18/2021] [Indexed: 06/13/2023]
Abstract
We propose a single-atom, cavity quantum electrodynamics system, compatible with recently demonstrated, fiber-integrated micro- and nanocavity setups, for the on-demand production of optical number-state, 0N-state, and binomial-code-state pulses. The scheme makes use of Raman transitions within an entire atomic ground-state hyperfine level and operates with laser and cavity fields detuned from the atomic transition by much more than the excited-state hyperfine splitting. This enables reduction of the dynamics to that of a simple, cavity-damped Tavis-Cummings model with the collective spin determined by the total angular momentum of the ground hyperfine level.
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Affiliation(s)
- Caspar Groiseau
- Dodd-Walls Centre for Photonic and Quantum Technologies, New Zealand
- Department of Physics, University of Auckland, Auckland 1010, New Zealand
| | - Alexander E J Elliott
- Dodd-Walls Centre for Photonic and Quantum Technologies, New Zealand
- Department of Physics, University of Auckland, Auckland 1010, New Zealand
| | - Stuart J Masson
- Department of Physics, Columbia University, 538 West 120th Street, New York, New York 10027-5255, USA
| | - Scott Parkins
- Dodd-Walls Centre for Photonic and Quantum Technologies, New Zealand
- Department of Physics, University of Auckland, Auckland 1010, New Zealand
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13
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Ren Z, Li W, Smerzi A, Gessner M. Metrological Detection of Multipartite Entanglement from Young Diagrams. PHYSICAL REVIEW LETTERS 2021; 126:080502. [PMID: 33709723 DOI: 10.1103/physrevlett.126.080502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Accepted: 01/13/2021] [Indexed: 06/12/2023]
Abstract
We characterize metrologically useful multipartite entanglement by representing partitions with Young diagrams. We derive entanglement witnesses that are sensitive to the shape of Young diagrams and show that Dyson's rank acts as a resource for quantum metrology. Common quantifiers, such as the entanglement depth and k-separability are contained in this approach as the diagram's width and height. Our methods are experimentally accessible in a wide range of atomic systems, as we illustrate by analyzing published data on the quantum Fisher information and spin-squeezing coefficients.
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Affiliation(s)
- Zhihong Ren
- Institute of Theoretical Physics and Department of Physics, State Key Laboratory of Quantum Optics and Quantum Optics Devices, Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan 030006, China
- Laboratoire Kastler Brossel, ENS-Université PSL, CNRS, Sorbonne Université, Collège de France, 24 Rue Lhomond, 75005 Paris, France
| | - Weidong Li
- Institute of Theoretical Physics and Department of Physics, State Key Laboratory of Quantum Optics and Quantum Optics Devices, Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan 030006, China
| | - Augusto Smerzi
- Institute of Theoretical Physics and Department of Physics, State Key Laboratory of Quantum Optics and Quantum Optics Devices, Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan 030006, China
- QSTAR, INO-CNR, and LENS, Largo Enrico Fermi 2, 50125 Firenze, Italy
| | - Manuel Gessner
- Laboratoire Kastler Brossel, ENS-Université PSL, CNRS, Sorbonne Université, Collège de France, 24 Rue Lhomond, 75005 Paris, France
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14
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Davis EJ, Periwal A, Cooper ES, Bentsen G, Evered SJ, Van Kirk K, Schleier-Smith MH. Protecting Spin Coherence in a Tunable Heisenberg Model. PHYSICAL REVIEW LETTERS 2020; 125:060402. [PMID: 32845652 DOI: 10.1103/physrevlett.125.060402] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Revised: 05/15/2020] [Accepted: 06/09/2020] [Indexed: 05/09/2023]
Abstract
Using an ensemble of atoms in an optical cavity, we engineer a family of nonlocal Heisenberg Hamiltonians with continuously tunable anisotropy of the spin-spin couplings. We thus gain access to a rich phase diagram, including a paramagnetic-to-ferromagnetic Ising phase transition that manifests as a diverging magnetic susceptibility at the critical point. The susceptibility displays a symmetry between Ising interactions and XY (spin-exchange) interactions of the opposite sign, which is indicative of the spatially extended atomic system behaving as a single collective spin. Images of the magnetization dynamics show that spin-exchange interactions protect the coherence of the collective spin, even against inhomogeneous fields that completely dephase the noninteracting and Ising systems. Our results underscore prospects for harnessing spin-exchange interactions to enhance the robustness of spin squeezing protocols.
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Affiliation(s)
- Emily J Davis
- Department of Physics, Stanford University, Stanford, California 94305, USA
| | - Avikar Periwal
- Department of Physics, Stanford University, Stanford, California 94305, USA
| | - Eric S Cooper
- Department of Physics, Stanford University, Stanford, California 94305, USA
| | - Gregory Bentsen
- Department of Physics, Stanford University, Stanford, California 94305, USA
- Department of Physics, Princeton University, Princeton, New Jersey 08540, USA
| | - Simon J Evered
- Department of Physics, Stanford University, Stanford, California 94305, USA
| | - Katherine Van Kirk
- Department of Physics, Stanford University, Stanford, California 94305, USA
| | - Monika H Schleier-Smith
- Department of Physics, Stanford University, Stanford, California 94305, USA
- SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
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15
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Muñoz JM, Wang X, Hewitt T, Kowalczyk AU, Sawant R, Barontini G. Dissipative Distillation of Supercritical Quantum Gases. PHYSICAL REVIEW LETTERS 2020; 125:020403. [PMID: 32701314 DOI: 10.1103/physrevlett.125.020403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2020] [Accepted: 06/22/2020] [Indexed: 06/11/2023]
Abstract
We experimentally realize a method to produce nonequilibrium Bose-Einstein condensates with condensed fraction exceeding those of equilibrium samples with the same parameters. To do this, we immerse an ultracold Bose gas of ^{87}Rb in a cloud of ^{39}K with substantially higher temperatures, providing a controlled source of dissipation. By combining the action of the dissipative environment with evaporative cooling, we are able to progressively distil the nonequilibrium Bose-Einstein condensate from the thermal cloud. We show that by increasing the strength of the dissipation it is even possible to produce condensates above the critical temperature. We finally demonstrate that our out-of-equilibrium samples are long lived and do not reach equilibrium in a time that is accessible for our experiment. Due to its high degree of control, our distillation process is a promising tool for the engineering of open quantum systems.
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Affiliation(s)
- Jorge Mellado Muñoz
- Midlands Ultracold Atom Research Centre, School Of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom
| | - Xi Wang
- Midlands Ultracold Atom Research Centre, School Of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom
| | - Thomas Hewitt
- Midlands Ultracold Atom Research Centre, School Of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom
| | - Anna U Kowalczyk
- Midlands Ultracold Atom Research Centre, School Of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom
| | - Rahul Sawant
- Midlands Ultracold Atom Research Centre, School Of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom
| | - Giovanni Barontini
- Midlands Ultracold Atom Research Centre, School Of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom
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16
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Garcia S, Ferri F, Reichel J, Long R. Overlapping two standing waves in a microcavity for a multi-atom photon interface. OPTICS EXPRESS 2020; 28:15515-15528. [PMID: 32403578 DOI: 10.1364/oe.392207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2020] [Accepted: 04/23/2020] [Indexed: 06/11/2023]
Abstract
We develop a light-matter interface enabling strong and uniform coupling between a chain of cold atoms and photons of an optical cavity. This interface is a fiber Fabry-Perot cavity, doubly resonant for both the wavelength of the atomic transition and for a geometrically commensurate red-detuned intracavity trapping lattice. Fulfilling the condition of a strong and uniform atom-photon coupling requires optimization of the spatial overlap between the two standing waves in the cavity. In a strong-coupling cavity, where the mode waists and Rayleigh range are small, we derive the expression of the optimal trapping wavelength, taking into account the Gouy phase. The main parameter controlling the overlap of the standing waves is the relative phase shift at the reflection on the cavity mirrors between the two wavelengths, for which we derive the optimal value. We have built a microcavity optimized according to these results, employing custom-made mirrors with engineered reflection phase for both wavelengths. We present a method to measure with high precision the relative phase shift at reflection, which allows us to determine the spatial overlap of the two modes in this cavity.
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17
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Ferri F, Garcia S, Baghdad M, Reichel J, Long R. Mapping optical standing-waves of an open-access Fabry-Perot cavity with a tapered fiber. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2020; 91:033104. [PMID: 32259942 DOI: 10.1063/1.5142709] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Accepted: 02/22/2020] [Indexed: 06/11/2023]
Abstract
We describe a method to map the standing-wave pattern inside an open-access Fabry-Perot optical cavity with sub-wavelength resolution by perturbing it with a commercially available tapered fiber. The method is applied to a fiber Fabry-Perot microcavity. We demonstrate its use in determining the relative position of the antinodes at two different wavelengths. In addition, we use the tapered optical fiber as a point-like source, allowing precise positioning of a microscope objective with respect to the cavity mode.
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Affiliation(s)
- Francesco Ferri
- Laboratoire Kastler Brossel, ENS-Université PSL, CNRS, Sorbonne Université, Collège de France, 24 rue Lhomond, 75005 Paris, France
| | - Sébastien Garcia
- Laboratoire Kastler Brossel, ENS-Université PSL, CNRS, Sorbonne Université, Collège de France, 24 rue Lhomond, 75005 Paris, France
| | - Mohamed Baghdad
- Laboratoire Kastler Brossel, ENS-Université PSL, CNRS, Sorbonne Université, Collège de France, 24 rue Lhomond, 75005 Paris, France
| | - Jakob Reichel
- Laboratoire Kastler Brossel, ENS-Université PSL, CNRS, Sorbonne Université, Collège de France, 24 rue Lhomond, 75005 Paris, France
| | - Romain Long
- Laboratoire Kastler Brossel, ENS-Université PSL, CNRS, Sorbonne Université, Collège de France, 24 rue Lhomond, 75005 Paris, France
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18
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Kaubruegger R, Silvi P, Kokail C, van Bijnen R, Rey AM, Ye J, Kaufman AM, Zoller P. Variational Spin-Squeezing Algorithms on Programmable Quantum Sensors. PHYSICAL REVIEW LETTERS 2019; 123:260505. [PMID: 31951449 DOI: 10.1103/physrevlett.123.260505] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Indexed: 06/10/2023]
Abstract
Arrays of atoms trapped in optical tweezers combine features of programmable analog quantum simulators with atomic quantum sensors. Here we propose variational quantum algorithms, tailored for tweezer arrays as programmable quantum sensors, capable of generating entangled states on demand for precision metrology. The scheme is designed to generate metrological enhancement by optimizing it in a feedback loop on the quantum device itself, thus preparing the best entangled states given the available quantum resources. We apply our ideas to the generation of spin-squeezed states on Sr atom tweezer arrays, where finite-range interactions are generated through Rydberg dressing. The complexity of experimental variational optimization of our quantum circuits is expected to scale favorably with system size. We numerically show our approach to be robust to noise, and surpassing known protocols.
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Affiliation(s)
- Raphael Kaubruegger
- Center for Quantum Physics, University of Innsbruck, Innsbruck A-6020, Austria
- Institute for Quantum Optics and Quantum Information of the Austrian Academy of Sciences, Innsbruck A-6020, Austria
| | - Pietro Silvi
- Center for Quantum Physics, University of Innsbruck, Innsbruck A-6020, Austria
- Institute for Quantum Optics and Quantum Information of the Austrian Academy of Sciences, Innsbruck A-6020, Austria
| | - Christian Kokail
- Center for Quantum Physics, University of Innsbruck, Innsbruck A-6020, Austria
- Institute for Quantum Optics and Quantum Information of the Austrian Academy of Sciences, Innsbruck A-6020, Austria
| | - Rick van Bijnen
- Center for Quantum Physics, University of Innsbruck, Innsbruck A-6020, Austria
- Institute for Quantum Optics and Quantum Information of the Austrian Academy of Sciences, Innsbruck A-6020, Austria
| | - Ana Maria Rey
- JILA, National Institute of Standards and Technology and University of Colorado and Department of Physics, University of Colorado, Boulder, Colorado 80309, USA
- Center for Theory of Quantum Matter, University of Colorado, Boulder, Colorado 80309, USA
| | - Jun Ye
- JILA, National Institute of Standards and Technology and University of Colorado and Department of Physics, University of Colorado, Boulder, Colorado 80309, USA
| | - Adam M Kaufman
- JILA, National Institute of Standards and Technology and University of Colorado and Department of Physics, University of Colorado, Boulder, Colorado 80309, USA
| | - Peter Zoller
- Center for Quantum Physics, University of Innsbruck, Innsbruck A-6020, Austria
- Institute for Quantum Optics and Quantum Information of the Austrian Academy of Sciences, Innsbruck A-6020, Austria
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19
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Garcia S, Stammeier M, Deiglmayr J, Merkt F, Wallraff A. Single-Shot Nondestructive Detection of Rydberg-Atom Ensembles by Transmission Measurement of a Microwave Cavity. PHYSICAL REVIEW LETTERS 2019; 123:193201. [PMID: 31765186 DOI: 10.1103/physrevlett.123.193201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Indexed: 06/10/2023]
Abstract
We present an experimental realization of single-shot nondestructive detection of ensembles of helium Rydberg atoms. We use the dispersive frequency shift of a superconducting microwave cavity interacting with the ensemble. By probing the transmission of the cavity, we determine the number of Rydberg atoms or the populations of Rydberg quantum states when the ensemble is prepared in a superposition. At the optimal microwave probe power, determined by the critical photon number, we reach single-shot detection of the atom number with 13% relative precision for ensembles of about 500 Rydberg atoms with a measurement backaction characterized by approximately 2% population transfer.
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Affiliation(s)
- S Garcia
- Department of Physics, ETH Zürich, CH-8093 Zürich, Switzerland
| | - M Stammeier
- Department of Physics, ETH Zürich, CH-8093 Zürich, Switzerland
| | - J Deiglmayr
- Laboratorium für Physikalische Chemie, ETH Zürich, CH-8093 Zürich, Switzerland
| | - F Merkt
- Laboratorium für Physikalische Chemie, ETH Zürich, CH-8093 Zürich, Switzerland
| | - A Wallraff
- Department of Physics, ETH Zürich, CH-8093 Zürich, Switzerland
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20
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Crespi A, Pepe FV, Facchi P, Sciarrino F, Mataloni P, Nakazato H, Pascazio S, Osellame R. Experimental Investigation of Quantum Decay at Short, Intermediate, and Long Times via Integrated Photonics. PHYSICAL REVIEW LETTERS 2019; 122:130401. [PMID: 31012619 DOI: 10.1103/physrevlett.122.130401] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Indexed: 05/14/2023]
Abstract
The decay of an unstable system is usually described by an exponential law. Quantum mechanics predicts strong deviations of the survival probability from the exponential: Indeed, the decay is initially quadratic, while at very large times it follows a power law, with superimposed oscillations. The latter regime is particularly elusive and difficult to observe. Here we employ arrays of single-mode optical waveguides, fabricated by femtosecond laser direct inscription, to implement quantum systems where a discrete state is coupled and can decay into a continuum. The optical modes correspond to distinct quantum states of the photon, and the temporal evolution of the quantum system is mapped into the spatial propagation coordinate. By injecting coherent light states in the fabricated photonic structures and by measuring a small scattered fraction of such light with an unprecedented dynamic range, we are able to experimentally observe not only the exponential decay regime, but also the quadratic Zeno region and the power-law decay at long evolution times.
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Affiliation(s)
- Andrea Crespi
- Dipartimento di Fisica, Politecnico di Milano, I-20133 Milano, Italy
- Istituto di Fotonica e Nanotecnologie, Consiglio Nazionale delle Ricerche, I-20133 Milano, Italy
| | | | - Paolo Facchi
- INFN, Sezione di Bari, I-70126 Bari, Italy
- Dipartimento di Fisica and MECENAS, Università di Bari, I-70126 Bari, Italy
| | - Fabio Sciarrino
- Dipartimento di Fisica, Sapienza Università di Roma, I-00185 Roma, Italy
| | - Paolo Mataloni
- Istituto di Fotonica e Nanotecnologie, Consiglio Nazionale delle Ricerche, I-20133 Milano, Italy
- Dipartimento di Fisica, Sapienza Università di Roma, I-00185 Roma, Italy
| | | | - Saverio Pascazio
- INFN, Sezione di Bari, I-70126 Bari, Italy
- Dipartimento di Fisica and MECENAS, Università di Bari, I-70126 Bari, Italy
- Istituto Nazionale di Ottica (INO-CNR), I-50125 Firenze, Italy
| | - Roberto Osellame
- Dipartimento di Fisica, Politecnico di Milano, I-20133 Milano, Italy
- Istituto di Fotonica e Nanotecnologie, Consiglio Nazionale delle Ricerche, I-20133 Milano, Italy
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21
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Davis EJ, Wang Z, Safavi-Naeini AH, Schleier-Smith MH. Painting Nonclassical States of Spin or Motion with Shaped Single Photons. PHYSICAL REVIEW LETTERS 2018; 121:123602. [PMID: 30296158 DOI: 10.1103/physrevlett.121.123602] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Indexed: 06/08/2023]
Abstract
We propose a robust scheme for generating macroscopic superposition states of spin or motion with the aid of a single photon. Shaping the wave packet of the photon enables high-fidelity preparation of nonclassical states of matter even in the presence of photon loss. Success is heralded by photodetection, enabling the scheme to be implemented with a weak coherent field. We analyze applications to preparing Schrödinger cat states of a collective atomic spin or of a mechanical oscillator coupled to an optical resonator. The method generalizes to preparing arbitrary superpositions of coherent states, enabling full quantum control. We illustrate this versatility by showing how to prepare Dicke or Fock states, as well as superpositions in the Dicke or Fock basis.
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Affiliation(s)
- Emily J Davis
- Department of Physics, Stanford University, Stanford, California 94305, USA
| | - Zhaoyou Wang
- Department of Applied Physics, Stanford University, Stanford, California 94305, USA
| | - Amir H Safavi-Naeini
- Department of Applied Physics, Stanford University, Stanford, California 94305, USA
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22
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Garcia S, Ferri F, Ott K, Reichel J, Long R. Dual-wavelength fiber Fabry-Perot cavities with engineered birefringence. OPTICS EXPRESS 2018; 26:22249-22263. [PMID: 30130920 DOI: 10.1364/oe.26.022249] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Accepted: 07/20/2018] [Indexed: 06/08/2023]
Abstract
We present a method to engineer the frequency splitting of polarization eigenmodes in fiber Fabry-Perot (FFP) cavities. Using specific patterns of multiple CO2 laser pulses, we machine paraboloidal micromirrors with controlled elliptical shape in a large range of radii of curvature. This method is versatile and can be used to produce cavities with maximized or near-zero polarization mode splitting. In addition, we realize dual-wavelength FFP cavities with finesse exceeding 40 000 at 780 nm and at 1559 nm in the telecom range. We provide direct evidence that the birefringent frequency splitting in FFP cavities is governed only by the geometrical shape of the mirrors, and that the astigmatism of the cavity modes needs to be taken into account for specific cavities.
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23
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Guo X, Zou CL, Jiang L, Tang HX. All-Optical Control of Linear and Nonlinear Energy Transfer via the Zeno Effect. PHYSICAL REVIEW LETTERS 2018; 120:203902. [PMID: 29864354 DOI: 10.1103/physrevlett.120.203902] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2018] [Indexed: 06/08/2023]
Abstract
Microresonator-based nonlinear processes are fundamental to applications including microcomb generation, parametric frequency conversion, and harmonics generation. While nonlinear processes involving either second- (χ^{(2)}) or third- (χ^{(3)}) order nonlinearity have been extensively studied, the interaction between these two basic nonlinear processes has seldom been reported. In this paper we demonstrate a coherent interplay between second- and third- order nonlinear processes. The parametric (χ^{(2)}) coupling to a lossy ancillary mode shortens the lifetime of the target photonic mode and suppresses its density of states, preventing the photon emissions into the target photonic mode via the Zeno effect. Such an effect is then used to control the stimulated four-wave mixing process and realize a suppression ratio of 34.5.
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Affiliation(s)
- Xiang Guo
- Department of Electrical Engineering, Yale University, New Haven, Connecticut 06511, USA
| | - Chang-Ling Zou
- Department of Electrical Engineering, Yale University, New Haven, Connecticut 06511, USA
- Department of Applied Physics, Yale University, New Haven, Connecticut 06511, USA
- Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Liang Jiang
- Department of Applied Physics, Yale University, New Haven, Connecticut 06511, USA
| | - Hong X Tang
- Department of Electrical Engineering, Yale University, New Haven, Connecticut 06511, USA
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24
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Yang D, Laflamme C, Vasilyev DV, Baranov MA, Zoller P. Theory of a Quantum Scanning Microscope for Cold Atoms. PHYSICAL REVIEW LETTERS 2018; 120:133601. [PMID: 29694173 DOI: 10.1103/physrevlett.120.133601] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Indexed: 06/08/2023]
Abstract
We propose and analyze a scanning microscope to monitor "live" the quantum dynamics of cold atoms in a cavity QED setup. The microscope measures the atomic density with subwavelength resolution via dispersive couplings to a cavity and homodyne detection within the framework of continuous measurement theory. We analyze two modes of operation. First, for a fixed focal point the microscope records the wave packet dynamics of atoms with time resolution set by the cavity lifetime. Second, a spatial scan of the microscope acts to map out the spatial density of stationary quantum states. Remarkably, in the latter case, for a good cavity limit, the microscope becomes an effective quantum nondemolition device, such that the spatial distribution of motional eigenstates can be measured backaction free in single scans, as an emergent quantum nondemolition measurement.
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Affiliation(s)
- D Yang
- Institute for Theoretical Physics, University of Innsbruck, A-6020 Innsbruck, Austria and Institute for Quantum Optics and Quantum Information of the Austrian Academy of Sciences, A-6020 Innsbruck, Austria
| | - C Laflamme
- Institute for Theoretical Physics, University of Innsbruck, A-6020 Innsbruck, Austria and Institute for Quantum Optics and Quantum Information of the Austrian Academy of Sciences, A-6020 Innsbruck, Austria
| | - D V Vasilyev
- Institute for Theoretical Physics, University of Innsbruck, A-6020 Innsbruck, Austria and Institute for Quantum Optics and Quantum Information of the Austrian Academy of Sciences, A-6020 Innsbruck, Austria
| | - M A Baranov
- Institute for Theoretical Physics, University of Innsbruck, A-6020 Innsbruck, Austria and Institute for Quantum Optics and Quantum Information of the Austrian Academy of Sciences, A-6020 Innsbruck, Austria
| | - P Zoller
- Institute for Theoretical Physics, University of Innsbruck, A-6020 Innsbruck, Austria and Institute for Quantum Optics and Quantum Information of the Austrian Academy of Sciences, A-6020 Innsbruck, Austria
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25
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Li DX, Shao XQ, Wu JH, Yi XX. Engineering steady-state entanglement via dissipation and quantum Zeno dynamics in an optical cavity. OPTICS LETTERS 2017; 42:3904-3907. [PMID: 28957157 DOI: 10.1364/ol.42.003904] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Accepted: 09/05/2017] [Indexed: 06/07/2023]
Abstract
A new mechanism is proposed for dissipatively preparing maximal Bell entangled state of two atoms in an optical cavity. This scheme integrates the spontaneous emission, the light shift of atoms in the presence of dispersive microwave field, and the quantum Zeno dynamics induced by continuous coupling, to obtain a unique steady state irrespective of initial state. Even for a large cavity decay, a high-fidelity entangled state is achievable at a short convergence time, since the occupation of the cavity mode is inhibited by the Zeno requirement. Therefore, a low single-atom cooperativity C=g2/(κγ) is good enough for realizing a high fidelity of entanglement in a wide range of decoherence parameters. As a straightforward extension, the feasibility for preparation of two-atom Knill-Laflamme-Milburn state with the same mechanism is also discussed.
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26
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Harrington PM, Monroe JT, Murch KW. Quantum Zeno Effects from Measurement Controlled Qubit-Bath Interactions. PHYSICAL REVIEW LETTERS 2017; 118:240401. [PMID: 28665648 DOI: 10.1103/physrevlett.118.240401] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Indexed: 06/07/2023]
Abstract
The Zeno and anti-Zeno effects are features of measurement-driven quantum evolution where frequent measurement inhibits or accelerates the decay of a quantum state. Either type of evolution can emerge depending on the system-environment interaction and measurement method. In this experiment, we use a superconducting qubit to map out both types of Zeno effect in the presence of structured noise baths and variable measurement rates. We observe both the suppression and acceleration of qubit decay as repeated measurements are used to modulate the qubit spectrum causing the qubit to sample different portions of the bath. We compare the Zeno effects arising from dispersive energy measurements and purely dephasing "quasimeasurements," showing energy measurements are not necessary to accelerate or suppress the decay process.
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Affiliation(s)
- P M Harrington
- Department of Physics, Washington University, Saint Louis, Missouri 63130, USA
| | - J T Monroe
- Department of Physics, Washington University, Saint Louis, Missouri 63130, USA
| | - K W Murch
- Department of Physics, Washington University, Saint Louis, Missouri 63130, USA
- Institute for Materials Science and Engineering, Saint Louis, Missouri 63130, USA
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27
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Gong Z, Higashikawa S, Ueda M. Zeno Hall Effect. PHYSICAL REVIEW LETTERS 2017; 118:200401. [PMID: 28581785 DOI: 10.1103/physrevlett.118.200401] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2016] [Indexed: 06/07/2023]
Abstract
We show that the quantum Zeno effect gives rise to the Hall effect by tailoring the Hilbert space of a two-dimensional lattice system into a single Bloch band with a nontrivial Berry curvature. Consequently, a wave packet undergoes transverse motion in response to a potential gradient-a phenomenon we call the Zeno Hall effect to highlight its quantum Zeno origin. The Zeno Hall effect leads to retroreflection at the edge of the system due to an interplay between the band flatness and the nontrivial Berry curvature. We propose an experimental implementation of this effect with ultracold atoms in an optical lattice.
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Affiliation(s)
- Zongping Gong
- Department of Physics, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Sho Higashikawa
- Department of Physics, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Masahito Ueda
- Department of Physics, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
- RIKEN Center for Emergent Matter Science (CEMS), Wako, Saitama 351-0198, Japan
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28
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Keil M, Amit O, Zhou S, Groswasser D, Japha Y, Folman R. Fifteen years of cold matter on the atom chip: promise, realizations, and prospects. JOURNAL OF MODERN OPTICS 2016; 63:1840-1885. [PMID: 27499585 PMCID: PMC4960518 DOI: 10.1080/09500340.2016.1178820] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Accepted: 03/22/2016] [Indexed: 05/30/2023]
Abstract
Here we review the field of atom chips in the context of Bose-Einstein Condensates (BEC) as well as cold matter in general. Twenty years after the first realization of the BEC and 15 years after the realization of the atom chip, the latter has been found to enable extraordinary feats: from producing BECs at a rate of several per second, through the realization of matter-wave interferometry, and all the way to novel probing of surfaces and new forces. In addition, technological applications are also being intensively pursued. This review will describe these developments and more, including new ideas which have not yet been realized.
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Affiliation(s)
- Mark Keil
- Department of Physics, Ben-Gurion University of the Negev, Be’er Sheva, Israel
| | - Omer Amit
- Department of Physics, Ben-Gurion University of the Negev, Be’er Sheva, Israel
| | - Shuyu Zhou
- Department of Physics, Ben-Gurion University of the Negev, Be’er Sheva, Israel
| | - David Groswasser
- Department of Physics, Ben-Gurion University of the Negev, Be’er Sheva, Israel
| | - Yonathan Japha
- Department of Physics, Ben-Gurion University of the Negev, Be’er Sheva, Israel
| | - Ron Folman
- Department of Physics, Ben-Gurion University of the Negev, Be’er Sheva, Israel
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29
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Kalb N, Cramer J, Twitchen DJ, Markham M, Hanson R, Taminiau TH. Experimental creation of quantum Zeno subspaces by repeated multi-spin projections in diamond. Nat Commun 2016; 7:13111. [PMID: 27713397 PMCID: PMC5059787 DOI: 10.1038/ncomms13111] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2016] [Accepted: 09/01/2016] [Indexed: 11/09/2022] Open
Abstract
Repeated observations inhibit the coherent evolution of quantum states through the quantum Zeno effect. In multi-qubit systems this effect provides opportunities to control complex quantum states. Here, we experimentally demonstrate that repeatedly projecting joint observables of multiple spins creates quantum Zeno subspaces and simultaneously suppresses the dephasing caused by a quasi-static environment. We encode up to two logical qubits in these subspaces and show that the enhancement of the dephasing time with increasing number of projections follows a scaling law that is independent of the number of spins involved. These results provide experimental insight into the interplay between frequent multi-spin measurements and slowly varying noise and pave the way for tailoring the dynamics of multi-qubit systems through repeated projections. Repeated observations of quantum states inhibit coherent evolution through the Zeno effect, providing opportunities for controlling multi-qubit systems. Here the authors demonstrate that projecting joint observables of three spins in diamond creates quantum Zeno subspaces that suppress dephasing.
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Affiliation(s)
- N Kalb
- QuTech, Delft University of Technology, P.O. Box 5046, Delft 2600 GA, The Netherlands.,Kavli Institute of Nanoscience, Delft University of Technology, P.O. Box 5046, Delft 2600 GA, The Netherlands
| | - J Cramer
- QuTech, Delft University of Technology, P.O. Box 5046, Delft 2600 GA, The Netherlands.,Kavli Institute of Nanoscience, Delft University of Technology, P.O. Box 5046, Delft 2600 GA, The Netherlands
| | - D J Twitchen
- Element Six Innovation, Fermi Avenue, Harwell Oxford, Didcot, Oxfordshire OX11 0QR, UK
| | - M Markham
- Element Six Innovation, Fermi Avenue, Harwell Oxford, Didcot, Oxfordshire OX11 0QR, UK
| | - R Hanson
- QuTech, Delft University of Technology, P.O. Box 5046, Delft 2600 GA, The Netherlands.,Kavli Institute of Nanoscience, Delft University of Technology, P.O. Box 5046, Delft 2600 GA, The Netherlands
| | - T H Taminiau
- QuTech, Delft University of Technology, P.O. Box 5046, Delft 2600 GA, The Netherlands.,Kavli Institute of Nanoscience, Delft University of Technology, P.O. Box 5046, Delft 2600 GA, The Netherlands
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30
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Lin Y, Gaebler JP, Reiter F, Tan TR, Bowler R, Wan Y, Keith A, Knill E, Glancy S, Coakley K, Sørensen AS, Leibfried D, Wineland DJ. Preparation of Entangled States through Hilbert Space Engineering. PHYSICAL REVIEW LETTERS 2016; 117:140502. [PMID: 27740826 DOI: 10.1103/physrevlett.117.140502] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Indexed: 06/06/2023]
Abstract
We apply laser fields to trapped atomic ions to constrain the quantum dynamics from a simultaneously applied global microwave field to an initial product state and a target entangled state. This approach comes under what has become known in the literature as "quantum Zeno dynamics" and we use it to prepare entangled states of two and three ions. With two trapped ^{9}Be^{+} ions, we obtain Bell state fidelities up to 0.990_{-5}^{+2}; with three ions, a W-state fidelity of 0.910_{-7}^{+4} is obtained. Compared to other methods of producing entanglement in trapped ions, this procedure can be relatively insensitive to certain imperfections such as fluctuations in laser intensity.
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Affiliation(s)
- Y Lin
- National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA
| | - J P Gaebler
- National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA
| | - F Reiter
- The Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, DK-2100 Copenhagen Ø, Denmark
| | - T R Tan
- National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA
| | - R Bowler
- National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA
| | - Y Wan
- National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA
| | - A Keith
- National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA
| | - E Knill
- National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA
| | - S Glancy
- National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA
| | - K Coakley
- National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA
| | - A S Sørensen
- The Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, DK-2100 Copenhagen Ø, Denmark
| | - D Leibfried
- National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA
| | - D J Wineland
- National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA
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