1
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Knaut CM, Suleymanzade A, Wei YC, Assumpcao DR, Stas PJ, Huan YQ, Machielse B, Knall EN, Sutula M, Baranes G, Sinclair N, De-Eknamkul C, Levonian DS, Bhaskar MK, Park H, Lončar M, Lukin MD. Entanglement of nanophotonic quantum memory nodes in a telecom network. Nature 2024; 629:573-578. [PMID: 38750231 PMCID: PMC11096112 DOI: 10.1038/s41586-024-07252-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2023] [Accepted: 02/28/2024] [Indexed: 05/18/2024]
Abstract
A key challenge in realizing practical quantum networks for long-distance quantum communication involves robust entanglement between quantum memory nodes connected by fibre optical infrastructure1-3. Here we demonstrate a two-node quantum network composed of multi-qubit registers based on silicon-vacancy (SiV) centres in nanophotonic diamond cavities integrated with a telecommunication fibre network. Remote entanglement is generated by the cavity-enhanced interactions between the electron spin qubits of the SiVs and optical photons. Serial, heralded spin-photon entangling gate operations with time-bin qubits are used for robust entanglement of separated nodes. Long-lived nuclear spin qubits are used to provide second-long entanglement storage and integrated error detection. By integrating efficient bidirectional quantum frequency conversion of photonic communication qubits to telecommunication frequencies (1,350 nm), we demonstrate the entanglement of two nuclear spin memories through 40 km spools of low-loss fibre and a 35-km long fibre loop deployed in the Boston area urban environment, representing an enabling step towards practical quantum repeaters and large-scale quantum networks.
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Affiliation(s)
- C M Knaut
- Department of Physics, Harvard University, Cambridge, MA, USA
| | - A Suleymanzade
- Department of Physics, Harvard University, Cambridge, MA, USA
| | - Y-C Wei
- Department of Physics, Harvard University, Cambridge, MA, USA
| | - D R Assumpcao
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
| | - P-J Stas
- Department of Physics, Harvard University, Cambridge, MA, USA
| | - Y Q Huan
- Department of Physics, Harvard University, Cambridge, MA, USA
| | - B Machielse
- Department of Physics, Harvard University, Cambridge, MA, USA
- AWS Center for Quantum Networking, Boston, MA, USA
| | - E N Knall
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
| | - M Sutula
- Department of Physics, Harvard University, Cambridge, MA, USA
| | - G Baranes
- Department of Physics, Harvard University, Cambridge, MA, USA
- Department of Physics and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - N Sinclair
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
| | | | - D S Levonian
- Department of Physics, Harvard University, Cambridge, MA, USA
- AWS Center for Quantum Networking, Boston, MA, USA
| | - M K Bhaskar
- Department of Physics, Harvard University, Cambridge, MA, USA
- AWS Center for Quantum Networking, Boston, MA, USA
| | - H Park
- Department of Physics, Harvard University, Cambridge, MA, USA
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
| | - M Lončar
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
| | - M D Lukin
- Department of Physics, Harvard University, Cambridge, MA, USA.
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2
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Drmota P, Nadlinger DP, Main D, Nichol BC, Ainley EM, Leichtle D, Mantri A, Kashefi E, Srinivas R, Araneda G, Ballance CJ, Lucas DM. Verifiable Blind Quantum Computing with Trapped Ions and Single Photons. PHYSICAL REVIEW LETTERS 2024; 132:150604. [PMID: 38682960 DOI: 10.1103/physrevlett.132.150604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Accepted: 01/16/2024] [Indexed: 05/01/2024]
Abstract
We report the first hybrid matter-photon implementation of verifiable blind quantum computing. We use a trapped-ion quantum server and a client-side photonic detection system networked via a fiber-optic quantum link. The availability of memory qubits and deterministic entangling gates enables interactive protocols without postselection-key requirements for any scalable blind server, which previous realizations could not provide. We quantify the privacy at ≲0.03 leaked classical bits per qubit. This experiment demonstrates a path to fully verified quantum computing in the cloud.
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Affiliation(s)
- P Drmota
- Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, United Kingdom
| | - D P Nadlinger
- Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, United Kingdom
| | - D Main
- Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, United Kingdom
| | - B C Nichol
- Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, United Kingdom
| | - E M Ainley
- Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, United Kingdom
| | - D Leichtle
- Laboratoire d'Informatique de Paris 6, CNRS, Sorbonne Université, Paris 75005, France
| | - A Mantri
- Joint Center for Quantum Information and Computer Science, University of Maryland, College Park, Maryland, USA
| | - E Kashefi
- Laboratoire d'Informatique de Paris 6, CNRS, Sorbonne Université, Paris 75005, France
- School of Informatics, University of Edinburgh, Edinburgh EH8 9AB, United Kingdom
| | - R Srinivas
- Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, United Kingdom
| | - G Araneda
- Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, United Kingdom
| | - C J Ballance
- Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, United Kingdom
| | - D M Lucas
- Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, United Kingdom
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3
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Adam F, Chiew WX, Utama AN, Kurtsiefer C. Low noise near-concentric optical cavity design. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2024; 95:043102. [PMID: 38602458 DOI: 10.1063/5.0191123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2023] [Accepted: 03/24/2024] [Indexed: 04/12/2024]
Abstract
Near-concentric cavities are excellent tools for enhancing an atom-light interaction as they combine a small mode volume with a large optical access for atom manipulation. However, they are sensitive to longitudinal and transverse misalignments. To address this sensitivity, we present a compact near-concentric optical cavity system with a residual cavity length variation δLC,rms = 0.36(2) Å. A key part of this system is a cage-like tensegrity mirror support structure that allows us to correct for longitudinal and transverse misalignments. The system is stable enough to allow the use of mirrors with a higher cavity finesse to enhance the atom-light coupling strength in cavity-QED applications.
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Affiliation(s)
- Florentin Adam
- Center for Quantum Technologies, 3 Science Drive 2, Singapore 117543
| | - Wen Xin Chiew
- Center for Quantum Technologies, 3 Science Drive 2, Singapore 117543
| | | | - Christian Kurtsiefer
- Center for Quantum Technologies, 3 Science Drive 2, Singapore 117543
- Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore 117542
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4
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Carter AL, O'Reilly J, Toh G, Saha S, Shalaev M, Goetting I, Monroe C. Ion trap with in-vacuum high numerical aperture imaging for a dual-species modular quantum computer. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2024; 95:033201. [PMID: 38477652 DOI: 10.1063/5.0180732] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Accepted: 02/25/2024] [Indexed: 03/14/2024]
Abstract
Photonic interconnects between quantum systems will play a central role in both scalable quantum computing and quantum networking. Entanglement of remote qubits via photons has been demonstrated in many platforms; however, improving the rate of entanglement generation will be instrumental for integrating photonic links into modular quantum computers. We present an ion trap system that has the highest reported free-space photon collection efficiency for quantum networking. We use a pair of in-vacuum aspheric lenses, each with a numerical aperture of 0.8, to couple 10(1)% of the 493 nm photons emitted from a 138Ba+ ion into single-mode fibers. We also demonstrate that proximal effects of the lenses on the ion position and motion can be mitigated.
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Affiliation(s)
- Allison L Carter
- Joint Quantum Institute and Department of Physics, University of Maryland, College Park, Maryland 20742, USA
| | - Jameson O'Reilly
- Joint Quantum Institute and Department of Physics, University of Maryland, College Park, Maryland 20742, USA
- Duke Quantum Center, Department of Electrical and Computer Engineering, Department of Physics, Duke University, Durham, North Carolina 27701, USA
| | - George Toh
- Joint Quantum Institute and Department of Physics, University of Maryland, College Park, Maryland 20742, USA
- Duke Quantum Center, Department of Electrical and Computer Engineering, Department of Physics, Duke University, Durham, North Carolina 27701, USA
| | - Sagnik Saha
- Joint Quantum Institute and Department of Physics, University of Maryland, College Park, Maryland 20742, USA
- Duke Quantum Center, Department of Electrical and Computer Engineering, Department of Physics, Duke University, Durham, North Carolina 27701, USA
| | - Mikhail Shalaev
- Duke Quantum Center, Department of Electrical and Computer Engineering, Department of Physics, Duke University, Durham, North Carolina 27701, USA
| | - Isabella Goetting
- Duke Quantum Center, Department of Electrical and Computer Engineering, Department of Physics, Duke University, Durham, North Carolina 27701, USA
| | - Christopher Monroe
- Joint Quantum Institute and Department of Physics, University of Maryland, College Park, Maryland 20742, USA
- Duke Quantum Center, Department of Electrical and Computer Engineering, Department of Physics, Duke University, Durham, North Carolina 27701, USA
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5
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Bilitewski T, Rey AM. Manipulating Growth and Propagation of Correlations in Dipolar Multilayers: From Pair Production to Bosonic Kitaev Models. PHYSICAL REVIEW LETTERS 2023; 131:053001. [PMID: 37595247 DOI: 10.1103/physrevlett.131.053001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Accepted: 07/14/2023] [Indexed: 08/20/2023]
Abstract
We study the nonequilibrium dynamics of dipoles confined in multiple stacked two-dimensional layers realizing a long-range interacting quantum spin 1/2 XXX model. We demonstrate that strong in-plane interactions can protect a manifold of collective layer dynamics. This then allows us to map the many-body spin dynamics to bosonic models. In a bilayer configuration we show how to engineer the paradigmatic two-mode squeezing Hamiltonian known from quantum optics, resulting in exponential production of entangled pairs and generation of metrologically useful entanglement from initially prepared product states. In multilayer configurations we engineer a bosonic variant of the Kitaev model displaying chiral propagation along the layer direction. Our study illustrates how the control over interactions, lattice geometry, and state preparation in interacting dipolar systems uniquely afforded by AMO platforms such as Rydberg and magnetic atoms, polar molecules, or trapped ions allows for the control over the temporal and spatial propagation of correlations for applications in quantum sensing and quantum simulation.
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Affiliation(s)
- Thomas Bilitewski
- Department of Physics, Oklahoma State University, Stillwater, Oklahoma 74078, USA
| | - Ana Maria Rey
- JILA, National Institute of Standards and Technology and Department of Physics, University of Colorado, Boulder, Colorado 80309, USA
- Center for Theory of Quantum Matter, University of Colorado, Boulder, Colorado 80309, USA
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6
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Krutyanskiy V, Canteri M, Meraner M, Bate J, Krcmarsky V, Schupp J, Sangouard N, Lanyon BP. Telecom-Wavelength Quantum Repeater Node Based on a Trapped-Ion Processor. PHYSICAL REVIEW LETTERS 2023; 130:213601. [PMID: 37295084 DOI: 10.1103/physrevlett.130.213601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Revised: 02/17/2023] [Accepted: 03/16/2023] [Indexed: 06/12/2023]
Abstract
A quantum repeater node is presented based on trapped ions that act as single-photon emitters, quantum memories, and an elementary quantum processor. The node's ability to establish entanglement across two 25-km-long optical fibers independently, then to swap that entanglement efficiently to extend it over both fibers, is demonstrated. The resultant entanglement is established between telecom-wavelength photons at either end of the 50 km channel. Finally, the system improvements to allow for repeater-node chains to establish stored entanglement over 800 km at hertz rates are calculated, revealing a near-term path to distributed networks of entangled sensors, atomic clocks, and quantum processors.
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Affiliation(s)
- V Krutyanskiy
- Institut für Experimentalphysik, Universität Innsbruck, Technikerstrasse 25, 6020 Innsbruck, Austria
- Institut für Quantenoptik und Quanteninformation, Osterreichische Akademie der Wissenschaften, Technikerstrasse 21a, 6020 Innsbruck, Austria
| | - M Canteri
- Institut für Experimentalphysik, Universität Innsbruck, Technikerstrasse 25, 6020 Innsbruck, Austria
- Institut für Quantenoptik und Quanteninformation, Osterreichische Akademie der Wissenschaften, Technikerstrasse 21a, 6020 Innsbruck, Austria
| | - M Meraner
- Institut für Experimentalphysik, Universität Innsbruck, Technikerstrasse 25, 6020 Innsbruck, Austria
- Institut für Quantenoptik und Quanteninformation, Osterreichische Akademie der Wissenschaften, Technikerstrasse 21a, 6020 Innsbruck, Austria
| | - J Bate
- Institut für Experimentalphysik, Universität Innsbruck, Technikerstrasse 25, 6020 Innsbruck, Austria
| | - V Krcmarsky
- Institut für Experimentalphysik, Universität Innsbruck, Technikerstrasse 25, 6020 Innsbruck, Austria
- Institut für Quantenoptik und Quanteninformation, Osterreichische Akademie der Wissenschaften, Technikerstrasse 21a, 6020 Innsbruck, Austria
| | - J Schupp
- Institut für Experimentalphysik, Universität Innsbruck, Technikerstrasse 25, 6020 Innsbruck, Austria
- Institut für Quantenoptik und Quanteninformation, Osterreichische Akademie der Wissenschaften, Technikerstrasse 21a, 6020 Innsbruck, Austria
| | - N Sangouard
- Institut de Physique Théorique, Université Paris-Saclay, CEA, CNRS, 91191 Gif-sur-Yvette, France
| | - B P Lanyon
- Institut für Experimentalphysik, Universität Innsbruck, Technikerstrasse 25, 6020 Innsbruck, Austria
- Institut für Quantenoptik und Quanteninformation, Osterreichische Akademie der Wissenschaften, Technikerstrasse 21a, 6020 Innsbruck, Austria
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7
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Iñesta ÁG, Vardoyan G, Scavuzzo L, Wehner S. Optimal entanglement distribution policies in homogeneous repeater chains with cutoffs. NPJ QUANTUM INFORMATION 2023; 9:46. [PMID: 38665258 PMCID: PMC11041801 DOI: 10.1038/s41534-023-00713-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Accepted: 04/17/2023] [Indexed: 04/28/2024]
Abstract
We study the limits of bipartite entanglement distribution using a chain of quantum repeaters that have quantum memories. To generate end-to-end entanglement, each node can attempt the generation of an entangled link with a neighbor, or perform an entanglement swapping measurement. A maximum storage time, known as cutoff, is enforced on the memories to ensure high-quality entanglement. Nodes follow a policy that determines when to perform each operation. Global-knowledge policies take into account all the information about the entanglement already produced. Here, we find global-knowledge policies that minimize the expected time to produce end-to-end entanglement. Our methods are based on Markov decision processes and value and policy iteration. We compare optimal policies to a policy in which nodes only use local information. We find that the advantage in expected delivery time provided by an optimal global-knowledge policy increases with increasing number of nodes and decreasing probability of successful swapping.
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Affiliation(s)
- Álvaro G. Iñesta
- QuTech, Delft University of Technology, Delft, The Netherlands
- EEMCS, Delft University of Technology, Delft, The Netherlands
- Kavli Institute of Nanoscience, Delft University of Technology, Delft, The Netherlands
| | - Gayane Vardoyan
- QuTech, Delft University of Technology, Delft, The Netherlands
- EEMCS, Delft University of Technology, Delft, The Netherlands
| | - Lara Scavuzzo
- EEMCS, Delft University of Technology, Delft, The Netherlands
| | - Stephanie Wehner
- QuTech, Delft University of Technology, Delft, The Netherlands
- EEMCS, Delft University of Technology, Delft, The Netherlands
- Kavli Institute of Nanoscience, Delft University of Technology, Delft, The Netherlands
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8
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DeAbreu A, Bowness C, Alizadeh A, Chartrand C, Brunelle NA, MacQuarrie ER, Lee-Hone NR, Ruether M, Kazemi M, Kurkjian ATK, Roorda S, Abrosimov NV, Pohl HJ, Thewalt MLW, Higginbottom DB, Simmons S. Waveguide-integrated silicon T centres. OPTICS EXPRESS 2023; 31:15045-15057. [PMID: 37157355 DOI: 10.1364/oe.482008] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
The performance of modular, networked quantum technologies will be strongly dependent upon the quality of their quantum light-matter interconnects. Solid-state colour centres, and in particular T centres in silicon, offer competitive technological and commercial advantages as the basis for quantum networking technologies and distributed quantum computing. These newly rediscovered silicon defects offer direct telecommunications-band photonic emission, long-lived electron and nuclear spin qubits, and proven native integration into industry-standard, CMOS-compatible, silicon-on-insulator (SOI) photonic chips at scale. Here we demonstrate further levels of integration by characterizing T centre spin ensembles in single-mode waveguides in SOI. In addition to measuring long spin T1 times, we report on the integrated centres' optical properties. We find that the narrow homogeneous linewidth of these waveguide-integrated emitters is already sufficiently low to predict the future success of remote spin-entangling protocols with only modest cavity Purcell enhancements. We show that further improvements may still be possible by measuring nearly lifetime-limited homogeneous linewidths in isotopically pure bulk crystals. In each case the measured linewidths are more than an order of magnitude lower than previously reported and further support the view that high-performance, large-scale distributed quantum technologies based upon T centres in silicon may be attainable in the near term.
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9
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Drmota P, Main D, Nadlinger DP, Nichol BC, Weber MA, Ainley EM, Agrawal A, Srinivas R, Araneda G, Ballance CJ, Lucas DM. Robust Quantum Memory in a Trapped-Ion Quantum Network Node. PHYSICAL REVIEW LETTERS 2023; 130:090803. [PMID: 36930909 DOI: 10.1103/physrevlett.130.090803] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Accepted: 01/19/2023] [Indexed: 06/18/2023]
Abstract
We integrate a long-lived memory qubit into a mixed-species trapped-ion quantum network node. Ion-photon entanglement first generated with a network qubit in ^{88}Sr^{+} is transferred to ^{43}Ca^{+} with 0.977(7) fidelity, and mapped to a robust memory qubit. We then entangle the network qubit with a second photon, without affecting the memory qubit. We perform quantum state tomography to show that the fidelity of ion-photon entanglement decays ∼70 times slower on the memory qubit. Dynamical decoupling further extends the storage duration; we measure an ion-photon entanglement fidelity of 0.81(4) after 10 s.
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Affiliation(s)
- P Drmota
- Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, United Kingdom
| | - D Main
- Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, United Kingdom
| | - D P Nadlinger
- Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, United Kingdom
| | - B C Nichol
- Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, United Kingdom
| | - M A Weber
- Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, United Kingdom
| | - E M Ainley
- Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, United Kingdom
| | - A Agrawal
- Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, United Kingdom
| | - R Srinivas
- Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, United Kingdom
| | - G Araneda
- Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, United Kingdom
| | - C J Ballance
- Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, United Kingdom
| | - D M Lucas
- Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, United Kingdom
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10
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Zaporski L, Shofer N, Bodey JH, Manna S, Gillard G, Appel MH, Schimpf C, Covre da Silva SF, Jarman J, Delamare G, Park G, Haeusler U, Chekhovich EA, Rastelli A, Gangloff DA, Atatüre M, Le Gall C. Ideal refocusing of an optically active spin qubit under strong hyperfine interactions. NATURE NANOTECHNOLOGY 2023; 18:257-263. [PMID: 36702953 DOI: 10.1038/s41565-022-01282-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Accepted: 10/28/2022] [Indexed: 06/18/2023]
Abstract
Combining highly coherent spin control with efficient light-matter coupling offers great opportunities for quantum communication and computing. Optically active semiconductor quantum dots have unparalleled photonic properties but also modest spin coherence limited by their resident nuclei. The nuclear inhomogeneity has thus far bound all dynamical decoupling measurements to a few microseconds. Here, we eliminate this inhomogeneity using lattice-matched GaAs-AlGaAs quantum dot devices and demonstrate dynamical decoupling of the electron spin qubit beyond 0.113(3) ms. Leveraging the 99.30(5)% visibility of our optical π-pulse gates, we use up to Nπ = 81 decoupling pulses and find a coherence time scaling of [Formula: see text]. This scaling manifests an ideal refocusing of strong interactions between the electron and the nuclear spin ensemble, free of extrinsic noise, which holds the promise of lifetime-limited spin coherence. Our findings demonstrate that the most punishing material science challenge for such quantum dot devices has a remedy and constitute the basis for highly coherent spin-photon interfaces.
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Affiliation(s)
- Leon Zaporski
- Cavendish Laboratory, University of Cambridge, Cambridge, United Kingdom.
| | - Noah Shofer
- Cavendish Laboratory, University of Cambridge, Cambridge, United Kingdom
| | - Jonathan H Bodey
- Cavendish Laboratory, University of Cambridge, Cambridge, United Kingdom
| | - Santanu Manna
- Institute of Semiconductor and Solid State Physics, Johannes Kepler University, Linz, Austria
- Department of Electrical Engineering, Indian Institute of Technology Delhi, New Delhi, India
| | - George Gillard
- Department of Physics and Astronomy, University of Sheffield, Sheffield, United Kingdom
| | | | - Christian Schimpf
- Institute of Semiconductor and Solid State Physics, Johannes Kepler University, Linz, Austria
| | | | - John Jarman
- Cavendish Laboratory, University of Cambridge, Cambridge, United Kingdom
| | - Geoffroy Delamare
- Cavendish Laboratory, University of Cambridge, Cambridge, United Kingdom
| | - Gunhee Park
- Cavendish Laboratory, University of Cambridge, Cambridge, United Kingdom
| | - Urs Haeusler
- Cavendish Laboratory, University of Cambridge, Cambridge, United Kingdom
| | - Evgeny A Chekhovich
- Department of Physics and Astronomy, University of Sheffield, Sheffield, United Kingdom
| | - Armando Rastelli
- Institute of Semiconductor and Solid State Physics, Johannes Kepler University, Linz, Austria
| | - Dorian A Gangloff
- Cavendish Laboratory, University of Cambridge, Cambridge, United Kingdom
- Department of Engineering Science, University of Oxford, Oxford, United Kingdom
| | - Mete Atatüre
- Cavendish Laboratory, University of Cambridge, Cambridge, United Kingdom.
| | - Claire Le Gall
- Cavendish Laboratory, University of Cambridge, Cambridge, United Kingdom.
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11
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Akhtar M, Bonus F, Lebrun-Gallagher FR, Johnson NI, Siegele-Brown M, Hong S, Hile SJ, Kulmiya SA, Weidt S, Hensinger WK. A high-fidelity quantum matter-link between ion-trap microchip modules. Nat Commun 2023; 14:531. [PMID: 36754957 PMCID: PMC9908934 DOI: 10.1038/s41467-022-35285-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Accepted: 11/25/2022] [Indexed: 02/10/2023] Open
Abstract
System scalability is fundamental for large-scale quantum computers (QCs) and is being pursued over a variety of hardware platforms. For QCs based on trapped ions, architectures such as the quantum charge-coupled device (QCCD) are used to scale the number of qubits on a single device. However, the number of ions that can be hosted on a single quantum computing module is limited by the size of the chip being used. Therefore, a modular approach is of critical importance and requires quantum connections between individual modules. Here, we present the demonstration of a quantum matter-link in which ion qubits are transferred between adjacent QC modules. Ion transport between adjacent modules is realised at a rate of 2424 s-1 and with an infidelity associated with ion loss during transport below 7 × 10-8. Furthermore, we show that the link does not measurably impact the phase coherence of the qubit. The quantum matter-link constitutes a practical mechanism for the interconnection of QCCD devices. Our work will facilitate the implementation of modular QCs capable of fault-tolerant utility-scale quantum computation.
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Affiliation(s)
- M. Akhtar
- grid.12082.390000 0004 1936 7590Sussex Centre for Quantum Technologies, University of Sussex, Brighton, BN1 9QH UK ,Universal Quantum Ltd, Brighton, BN1 6SB UK
| | - F. Bonus
- Universal Quantum Ltd, Brighton, BN1 6SB UK ,grid.83440.3b0000000121901201Department of Physics and Astronomy, University College London, London, WC1E 6BT UK
| | - F. R. Lebrun-Gallagher
- grid.12082.390000 0004 1936 7590Sussex Centre for Quantum Technologies, University of Sussex, Brighton, BN1 9QH UK ,Universal Quantum Ltd, Brighton, BN1 6SB UK
| | - N. I. Johnson
- grid.12082.390000 0004 1936 7590Sussex Centre for Quantum Technologies, University of Sussex, Brighton, BN1 9QH UK
| | - M. Siegele-Brown
- grid.12082.390000 0004 1936 7590Sussex Centre for Quantum Technologies, University of Sussex, Brighton, BN1 9QH UK
| | - S. Hong
- grid.12082.390000 0004 1936 7590Sussex Centre for Quantum Technologies, University of Sussex, Brighton, BN1 9QH UK
| | - S. J. Hile
- grid.12082.390000 0004 1936 7590Sussex Centre for Quantum Technologies, University of Sussex, Brighton, BN1 9QH UK
| | - S. A. Kulmiya
- grid.12082.390000 0004 1936 7590Sussex Centre for Quantum Technologies, University of Sussex, Brighton, BN1 9QH UK ,grid.5337.20000 0004 1936 7603Quantum Engineering Centre for Doctoral Training, University of Bristol, Bristol, BS8 1TH UK
| | - S. Weidt
- grid.12082.390000 0004 1936 7590Sussex Centre for Quantum Technologies, University of Sussex, Brighton, BN1 9QH UK ,Universal Quantum Ltd, Brighton, BN1 6SB UK
| | - W. K. Hensinger
- grid.12082.390000 0004 1936 7590Sussex Centre for Quantum Technologies, University of Sussex, Brighton, BN1 9QH UK ,Universal Quantum Ltd, Brighton, BN1 6SB UK
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12
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Krutyanskiy V, Galli M, Krcmarsky V, Baier S, Fioretto DA, Pu Y, Mazloom A, Sekatski P, Canteri M, Teller M, Schupp J, Bate J, Meraner M, Sangouard N, Lanyon BP, Northup TE. Entanglement of Trapped-Ion Qubits Separated by 230 Meters. PHYSICAL REVIEW LETTERS 2023; 130:050803. [PMID: 36800448 DOI: 10.1103/physrevlett.130.050803] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2022] [Accepted: 12/20/2022] [Indexed: 06/18/2023]
Abstract
We report on an elementary quantum network of two atomic ions separated by 230 m. The ions are trapped in different buildings and connected with 520(2) m of optical fiber. At each network node, the electronic state of an ion is entangled with the polarization state of a single cavity photon; subsequent to interference of the photons at a beam splitter, photon detection heralds entanglement between the two ions. Fidelities of up to (88.0+2.2-4.7)% are achieved with respect to a maximally entangled Bell state, with a success probability of 4×10^{-5}. We analyze the routes to improve these metrics, paving the way for long-distance networks of entangled quantum processors.
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Affiliation(s)
- V Krutyanskiy
- Institut für Quantenoptik und Quanteninformation, Österreichische Akademie der Wissenschaften, Technikerstraße 21a, 6020 Innsbruck, Austria
- Institut für Experimentalphysik, Universität Innsbruck, Technikerstraße 25, 6020 Innsbruck, Austria
| | - M Galli
- Institut für Experimentalphysik, Universität Innsbruck, Technikerstraße 25, 6020 Innsbruck, Austria
| | - V Krcmarsky
- Institut für Quantenoptik und Quanteninformation, Österreichische Akademie der Wissenschaften, Technikerstraße 21a, 6020 Innsbruck, Austria
- Institut für Experimentalphysik, Universität Innsbruck, Technikerstraße 25, 6020 Innsbruck, Austria
| | - S Baier
- Institut für Experimentalphysik, Universität Innsbruck, Technikerstraße 25, 6020 Innsbruck, Austria
| | - D A Fioretto
- Institut für Experimentalphysik, Universität Innsbruck, Technikerstraße 25, 6020 Innsbruck, Austria
| | - Y Pu
- Institut für Experimentalphysik, Universität Innsbruck, Technikerstraße 25, 6020 Innsbruck, Austria
| | - A Mazloom
- Department of Physics, Georgetown University, 37th and O Streets NW, Washington, D.C. 20057, USA
| | - P Sekatski
- Department of Applied Physics, University of Geneva, 1211 Geneva, Switzerland
| | - M Canteri
- Institut für Quantenoptik und Quanteninformation, Österreichische Akademie der Wissenschaften, Technikerstraße 21a, 6020 Innsbruck, Austria
- Institut für Experimentalphysik, Universität Innsbruck, Technikerstraße 25, 6020 Innsbruck, Austria
| | - M Teller
- Institut für Experimentalphysik, Universität Innsbruck, Technikerstraße 25, 6020 Innsbruck, Austria
| | - J Schupp
- Institut für Quantenoptik und Quanteninformation, Österreichische Akademie der Wissenschaften, Technikerstraße 21a, 6020 Innsbruck, Austria
- Institut für Experimentalphysik, Universität Innsbruck, Technikerstraße 25, 6020 Innsbruck, Austria
| | - J Bate
- Institut für Experimentalphysik, Universität Innsbruck, Technikerstraße 25, 6020 Innsbruck, Austria
| | - M Meraner
- Institut für Quantenoptik und Quanteninformation, Österreichische Akademie der Wissenschaften, Technikerstraße 21a, 6020 Innsbruck, Austria
- Institut für Experimentalphysik, Universität Innsbruck, Technikerstraße 25, 6020 Innsbruck, Austria
| | - N Sangouard
- Institut de Physique Théorique, Université Paris-Saclay, CEA, CNRS, 91191 Gif-sur-Yvette, France
| | - B P Lanyon
- Institut für Quantenoptik und Quanteninformation, Österreichische Akademie der Wissenschaften, Technikerstraße 21a, 6020 Innsbruck, Austria
- Institut für Experimentalphysik, Universität Innsbruck, Technikerstraße 25, 6020 Innsbruck, Austria
| | - T E Northup
- Institut für Experimentalphysik, Universität Innsbruck, Technikerstraße 25, 6020 Innsbruck, Austria
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13
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Qasymeh M, Eleuch H. High-fidelity quantum information transmission using a room-temperature nonrefrigerated lossy microwave waveguide. Sci Rep 2022; 12:16352. [PMID: 36175489 PMCID: PMC9522659 DOI: 10.1038/s41598-022-20733-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2022] [Accepted: 09/19/2022] [Indexed: 11/08/2022] Open
Abstract
Quantum microwave transmission is key to realizing modular superconducting quantum computers and distributed quantum networks. A large number of incoherent photons are thermally generated within the microwave frequency spectrum. The closeness of the transmitted quantum state to the source-generated quantum state at the input of the transmission link (measured by the transmission fidelity) degrades due to the presence of the incoherent photons. Hence, high-fidelity quantum microwave transmission has long been considered to be infeasible without refrigeration. In this study, we propose a novel method for high-fidelity quantum microwave transmission using a room-temperature lossy waveguide. The proposed scheme consists of connecting two cryogenic nodes (i.e., a transmitter and a receiver) by the room-temperature lossy microwave waveguide. First, cryogenic preamplification is implemented prior to transmission. Second, at the receiver side, a cryogenic loop antenna is placed inside the output port of the waveguide and coupled to an LC harmonic oscillator located outside the waveguide. The loop antenna converts quantum microwave fields to a quantum voltage across the coupled LC harmonic oscillator. Noise photons are induced across the LC oscillator including the source generated noise, the preamplification noise, the thermal occupation of the waveguide, and the fluctuation-dissipation noise. The loop antenna detector at the receiver is designed to extensively suppress the induced photons across the LC oscillator. The signal transmittance is maintained intact by providing significant preamplification gain. Our calculations show that high-fidelity quantum transmission (i.e., more than [Formula: see text]) is realized based on the proposed scheme for transmission distances reaching 100 m.
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Affiliation(s)
- Montasir Qasymeh
- Electrical and Computer Engineering Department, Abu Dhabi University, 59911, Abu Dhabi, United Arab Emirates.
| | - Hichem Eleuch
- Department of Applied Physics and Astronomy, University of Sharjah, Sharjah, United Arab Emirates
- Institute for Quantum Science and Engineering, Texas AM University, College Station, TX, 77843, USA
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14
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Nichol BC, Srinivas R, Nadlinger DP, Drmota P, Main D, Araneda G, Ballance CJ, Lucas DM. An elementary quantum network of entangled optical atomic clocks. Nature 2022; 609:689-694. [PMID: 36071166 DOI: 10.1038/s41586-022-05088-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Accepted: 07/07/2022] [Indexed: 11/09/2022]
Abstract
Optical atomic clocks are our most precise tools to measure time and frequency1-3. Precision frequency comparisons between clocks in separate locations enable one to probe the space-time variation of fundamental constants4,5 and the properties of dark matter6,7, to perform geodesy8-10 and to evaluate systematic clock shifts. Measurements on independent systems are limited by the standard quantum limit; measurements on entangled systems can surpass the standard quantum limit to reach the ultimate precision allowed by quantum theory-the Heisenberg limit. Although local entangling operations have demonstrated this enhancement at microscopic distances11-16, comparisons between remote atomic clocks require the rapid generation of high-fidelity entanglement between systems that have no intrinsic interactions. Here we report the use of a photonic link17,18 to entangle two 88Sr+ ions separated by a macroscopic distance19 (approximately 2 m) to demonstrate an elementary quantum network of entangled optical clocks. For frequency comparisons between the ions, we find that entanglement reduces the measurement uncertainty by nearly [Formula: see text], the value predicted for the Heisenberg limit. Today's optical clocks are typically limited by dephasing of the probe laser20; in this regime, we find that entanglement yields a factor of 2 reduction in the measurement uncertainty compared with conventional correlation spectroscopy techniques20-22. We demonstrate this enhancement for the measurement of a frequency shift applied to one of the clocks. This two-node network could be extended to additional nodes23, to other species of trapped particles or-through local operations-to larger entangled systems.
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Affiliation(s)
- B C Nichol
- Department of Physics, Clarendon Laboratory, University of Oxford, Oxford, UK.
| | - R Srinivas
- Department of Physics, Clarendon Laboratory, University of Oxford, Oxford, UK.
| | - D P Nadlinger
- Department of Physics, Clarendon Laboratory, University of Oxford, Oxford, UK
| | - P Drmota
- Department of Physics, Clarendon Laboratory, University of Oxford, Oxford, UK
| | - D Main
- Department of Physics, Clarendon Laboratory, University of Oxford, Oxford, UK
| | - G Araneda
- Department of Physics, Clarendon Laboratory, University of Oxford, Oxford, UK
| | - C J Ballance
- Department of Physics, Clarendon Laboratory, University of Oxford, Oxford, UK
| | - D M Lucas
- Department of Physics, Clarendon Laboratory, University of Oxford, Oxford, UK
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15
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Zhai L, Nguyen GN, Spinnler C, Ritzmann J, Löbl MC, Wieck AD, Ludwig A, Javadi A, Warburton RJ. Quantum interference of identical photons from remote GaAs quantum dots. NATURE NANOTECHNOLOGY 2022; 17:829-833. [PMID: 35589820 DOI: 10.1038/s41565-022-01131-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Accepted: 04/01/2022] [Indexed: 06/15/2023]
Abstract
Photonic quantum technology provides a viable route to quantum communication1,2, quantum simulation3 and quantum information processing4. Recent progress has seen the realization of boson sampling using 20 single photons3 and quantum key distribution over hundreds of kilometres2. Scaling the complexity requires architectures containing multiple photon sources, photon counters and a large number of indistinguishable single photons. Semiconductor quantum dots are bright and fast sources of coherent single photons5-9. For applications, a roadblock is the poor quantum coherence on interfering single photons created by independent quantum dots10,11. Here we demonstrate two-photon interference with near-unity visibility (93.0 ± 0.8)% using photons from two completely separate GaAs quantum dots. The experiment retains all the emission into the zero phonon line-only the weak phonon sideband is rejected; temporal post-selection is not employed. By exploiting quantum interference, we demonstrate a photonic controlled-not circuit and an entanglement with fidelity of (85.0 ± 1.0)% between photons of different origins. The two-photon interference visibility is high enough that the entanglement fidelity is well above the classical threshold. The high mutual coherence of the photons stems from high-quality materials, diode structure and relatively large quantum dot size. Our results establish a platform-GaAs quantum dots-for creating coherent single photons in a scalable way.
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Affiliation(s)
- Liang Zhai
- Department of Physics, University of Basel, Basel, Switzerland.
| | - Giang N Nguyen
- Department of Physics, University of Basel, Basel, Switzerland
| | | | - Julian Ritzmann
- Lehrstuhl für Angewandte Festkörperphysik, Ruhr-Universität Bochum, Bochum, Germany
| | - Matthias C Löbl
- Department of Physics, University of Basel, Basel, Switzerland
| | - Andreas D Wieck
- Lehrstuhl für Angewandte Festkörperphysik, Ruhr-Universität Bochum, Bochum, Germany
| | - Arne Ludwig
- Lehrstuhl für Angewandte Festkörperphysik, Ruhr-Universität Bochum, Bochum, Germany
| | - Alisa Javadi
- Department of Physics, University of Basel, Basel, Switzerland
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16
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Nadlinger DP, Drmota P, Nichol BC, Araneda G, Main D, Srinivas R, Lucas DM, Ballance CJ, Ivanov K, Tan EYZ, Sekatski P, Urbanke RL, Renner R, Sangouard N, Bancal JD. Experimental quantum key distribution certified by Bell's theorem. Nature 2022; 607:682-686. [PMID: 35896644 DOI: 10.1038/s41586-022-04941-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Accepted: 06/07/2022] [Indexed: 11/09/2022]
Abstract
Cryptographic key exchange protocols traditionally rely on computational conjectures such as the hardness of prime factorization1 to provide security against eavesdropping attacks. Remarkably, quantum key distribution protocols such as the Bennett-Brassard scheme2 provide information-theoretic security against such attacks, a much stronger form of security unreachable by classical means. However, quantum protocols realized so far are subject to a new class of attacks exploiting a mismatch between the quantum states or measurements implemented and their theoretical modelling, as demonstrated in numerous experiments3-6. Here we present the experimental realization of a complete quantum key distribution protocol immune to these vulnerabilities, following Ekert's pioneering proposal7 to use entanglement to bound an adversary's information from Bell's theorem8. By combining theoretical developments with an improved optical fibre link generating entanglement between two trapped-ion qubits, we obtain 95,628 key bits with device-independent security9-12 from 1.5 million Bell pairs created during eight hours of run time. We take steps to ensure that information on the measurement results is inaccessible to an eavesdropper. These measurements are performed without space-like separation. Our result shows that provably secure cryptography under general assumptions is possible with real-world devices, and paves the way for further quantum information applications based on the device-independence principle.
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Affiliation(s)
- D P Nadlinger
- Clarendon Laboratory, Department of Physics, University of Oxford, Oxford, UK.
| | - P Drmota
- Clarendon Laboratory, Department of Physics, University of Oxford, Oxford, UK
| | - B C Nichol
- Clarendon Laboratory, Department of Physics, University of Oxford, Oxford, UK
| | - G Araneda
- Clarendon Laboratory, Department of Physics, University of Oxford, Oxford, UK
| | - D Main
- Clarendon Laboratory, Department of Physics, University of Oxford, Oxford, UK
| | - R Srinivas
- Clarendon Laboratory, Department of Physics, University of Oxford, Oxford, UK
| | - D M Lucas
- Clarendon Laboratory, Department of Physics, University of Oxford, Oxford, UK
| | - C J Ballance
- Clarendon Laboratory, Department of Physics, University of Oxford, Oxford, UK.
| | - K Ivanov
- School of Computer and Communication Sciences, EPFL, Lausanne, Switzerland
| | - E Y-Z Tan
- Institute for Theoretical Physics, ETH Zürich, Zürich, Switzerland
| | - P Sekatski
- Department of Applied Physics, University of Geneva, Geneva, Switzerland
| | - R L Urbanke
- School of Computer and Communication Sciences, EPFL, Lausanne, Switzerland
| | - R Renner
- Institute for Theoretical Physics, ETH Zürich, Zürich, Switzerland
| | - N Sangouard
- Université Paris-Saclay, CEA, CNRS, Institut de Physique Théorique, Gif-sur-Yvette, France.
| | - J-D Bancal
- Université Paris-Saclay, CEA, CNRS, Institut de Physique Théorique, Gif-sur-Yvette, France.
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17
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Cohen LZ, Kim IH, Bartlett SD, Brown BJ. Low-overhead fault-tolerant quantum computing using long-range connectivity. SCIENCE ADVANCES 2022; 8:eabn1717. [PMID: 35594359 PMCID: PMC10926894 DOI: 10.1126/sciadv.abn1717] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Accepted: 04/06/2022] [Indexed: 06/15/2023]
Abstract
Vast numbers of qubits will be needed for large-scale quantum computing because of the overheads associated with error correction. We present a scheme for low-overhead fault-tolerant quantum computation based on quantum low-density parity-check (LDPC) codes, where long-range interactions enable many logical qubits to be encoded with a modest number of physical qubits. In our approach, logic gates operate via logical Pauli measurements that preserve both the protection of the LDPC codes and the low overheads in terms of the required number of additional qubits. Compared with surface codes with the same code distance, we estimate order-of-magnitude improvements in the overheads for processing around 100 logical qubits using this approach. Given the high thresholds demonstrated by LDPC codes, our estimates suggest that fault-tolerant quantum computation at this scale may be achievable with a few thousand physical qubits at comparable error rates to what is needed for current approaches.
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Affiliation(s)
- Lawrence Z. Cohen
- Centre for Engineered Quantum Systems, School of Physics, University of Sydney, Sydney, New South Wales 2006, Australia
| | - Isaac H. Kim
- Centre for Engineered Quantum Systems, School of Physics, University of Sydney, Sydney, New South Wales 2006, Australia
- Department of Computer Science, UC Davis, Davis, CA 95616, USA
| | - Stephen D. Bartlett
- Centre for Engineered Quantum Systems, School of Physics, University of Sydney, Sydney, New South Wales 2006, Australia
| | - Benjamin J. Brown
- Centre for Engineered Quantum Systems, School of Physics, University of Sydney, Sydney, New South Wales 2006, Australia
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18
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An D, Alonso AM, Matthiesen C, Häffner H. Coupling Two Laser-Cooled Ions via a Room-Temperature Conductor. PHYSICAL REVIEW LETTERS 2022; 128:063201. [PMID: 35213172 DOI: 10.1103/physrevlett.128.063201] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Accepted: 11/22/2021] [Indexed: 06/14/2023]
Abstract
We demonstrate coupling between the motions of two independently trapped ions with a separation distance of 620 μm. The ion-ion interaction is enhanced via a room-temperature electrically floating metallic wire which connects two surface traps. Tuning the motion of both ions into resonance, we show flow of energy with a coupling rate of 11 Hz. Quantum-coherent coupling is hindered by strong surface electric-field noise in our device. Our ion-wire-ion system demonstrates that room-temperature conductors can be used to mediate and tune interactions between independently trapped charges over distances beyond those achievable with free-space dipole-dipole coupling. This technology may be used to sympathetically cool or entangle remotely trapped charges and enable coupling between disparate physical systems.
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Affiliation(s)
- Da An
- Department of Physics, University of California, Berkeley, California 94720, USA
| | - Alberto M Alonso
- Department of Physics, University of California, Berkeley, California 94720, USA
| | - Clemens Matthiesen
- Department of Physics, University of California, Berkeley, California 94720, USA
| | - Hartmut Häffner
- Department of Physics, University of California, Berkeley, California 94720, USA
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19
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Hansenne K, Xu ZP, Kraft T, Gühne O. Symmetries in quantum networks lead to no-go theorems for entanglement distribution and to verification techniques. Nat Commun 2022; 13:496. [PMID: 35078999 PMCID: PMC8789828 DOI: 10.1038/s41467-022-28006-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Accepted: 12/27/2021] [Indexed: 11/30/2022] Open
Abstract
Quantum networks are promising tools for the implementation of long-range quantum communication. The characterization of quantum correlations in networks and their usefulness for information processing is therefore central for the progress of the field, but so far only results for small basic network structures or pure quantum states are known. Here we show that symmetries provide a versatile tool for the analysis of correlations in quantum networks. We provide an analytical approach to characterize correlations in large network structures with arbitrary topologies. As examples, we show that entangled quantum states with a bosonic or fermionic symmetry can not be generated in networks; moreover, cluster and graph states are not accessible. Our methods can be used to design certification methods for the functionality of specific links in a network and have implications for the design of future network structures.
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Affiliation(s)
- Kiara Hansenne
- Naturwissenschaftlich-Technische Fakultät, Universität Siegen, Siegen, Germany
| | - Zhen-Peng Xu
- Naturwissenschaftlich-Technische Fakultät, Universität Siegen, Siegen, Germany.
| | - Tristan Kraft
- Naturwissenschaftlich-Technische Fakultät, Universität Siegen, Siegen, Germany
- Institute for Theoretical Physics, University of Innsbruck, Innsbruck, Austria
| | - Otfried Gühne
- Naturwissenschaftlich-Technische Fakultät, Universität Siegen, Siegen, Germany
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20
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Lee J, Jeon DJ, Yeo JS. Quantum Plasmonics: Energy Transport Through Plasmonic Gap. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021; 33:e2006606. [PMID: 33891781 DOI: 10.1002/adma.202006606] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 11/12/2020] [Indexed: 06/12/2023]
Abstract
At the interfaces of metal and dielectric materials, strong light-matter interactions excite surface plasmons; this allows electromagnetic field confinement and enhancement on the sub-wavelength scale. Such phenomena have attracted considerable interest in the field of exotic material-based nanophotonic research, with potential applications including nonlinear spectroscopies, information processing, single-molecule sensing, organic-molecule devices, and plasmon chemistry. These innovative plasmonics-based technologies can meet the ever-increasing demands for speed and capacity in nanoscale devices, offering ultrasensitive detection capabilities and low-power operations. Size scaling from the nanometer to sub-nanometer ranges is consistently researched; as a result, the quantum behavior of localized surface plasmons, as well as those of matter, nonlocality, and quantum electron tunneling is investigated using an innovative nanofabrication and chemical functionalization approach, thereby opening a new era of quantum plasmonics. This new field enables the ultimate miniaturization of photonic components and provides extreme limits on light-matter interactions, permitting energy transport across the extremely small plasmonic gap. In this review, a comprehensive overview of the recent developments of quantum plasmonic resonators with particular focus on novel materials is presented. By exploring the novel gap materials in quantum regime, the potential quantum technology applications are also searched for and mapped out.
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Affiliation(s)
- Jihye Lee
- School of Integrated Technology, Yonsei University, Incheon, 21983, Republic of Korea
- Yonsei Institute of Convergence Technology, Yonsei University, Incheon, 21983, Republic of Korea
| | - Deok-Jin Jeon
- School of Integrated Technology, Yonsei University, Incheon, 21983, Republic of Korea
- Yonsei Institute of Convergence Technology, Yonsei University, Incheon, 21983, Republic of Korea
| | - Jong-Souk Yeo
- School of Integrated Technology, Yonsei University, Incheon, 21983, Republic of Korea
- Yonsei Institute of Convergence Technology, Yonsei University, Incheon, 21983, Republic of Korea
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21
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de Leon NP, Itoh KM, Kim D, Mehta KK, Northup TE, Paik H, Palmer BS, Samarth N, Sangtawesin S, Steuerman DW. Materials challenges and opportunities for quantum computing hardware. Science 2021; 372:372/6539/eabb2823. [PMID: 33859004 DOI: 10.1126/science.abb2823] [Citation(s) in RCA: 55] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Quantum computing hardware technologies have advanced during the past two decades, with the goal of building systems that can solve problems that are intractable on classical computers. The ability to realize large-scale systems depends on major advances in materials science, materials engineering, and new fabrication techniques. We identify key materials challenges that currently limit progress in five quantum computing hardware platforms, propose how to tackle these problems, and discuss some new areas for exploration. Addressing these materials challenges will require scientists and engineers to work together to create new, interdisciplinary approaches beyond the current boundaries of the quantum computing field.
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Affiliation(s)
- Nathalie P de Leon
- Department of Electrical Engineering, Princeton University, Princeton, NJ 08544, USA
| | - Kohei M Itoh
- School of Fundamental Science and Technology, Keio University, Yokohama 223-8522, Japan
| | - Dohun Kim
- Department of Physics and Astronomy and Institute of Applied Physics, Seoul National University, Seoul 08826, Korea
| | - Karan K Mehta
- Department of Physics, Institute for Quantum Electronics, ETH Zürich, 8092 Zürich, Switzerland
| | - Tracy E Northup
- Institut für Experimentalphysik, Universität Innsbruck, 6020 Innsbruck, Austria
| | - Hanhee Paik
- IBM Quantum, IBM T. J. Watson Research Center, Yorktown Heights, NY 10598, USA.
| | - B S Palmer
- Laboratory for Physical Sciences, University of Maryland, College Park, MD 20740, USA.,Quantum Materials Center, University of Maryland, College Park, MD 20742, USA
| | - N Samarth
- Department of Physics, The Pennsylvania State University, University Park, PA 16802, USA
| | - Sorawis Sangtawesin
- School of Physics and Center of Excellence in Advanced Functional Materials, Suranaree University of Technology, Nakhon Ratchasima 30000, Thailand
| | - D W Steuerman
- Kavli Foundation, 5715 Mesmer Avenue, Los Angeles, CA 90230, USA
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22
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Pompili M, Hermans SLN, Baier S, Beukers HKC, Humphreys PC, Schouten RN, Vermeulen RFL, Tiggelman MJ, Dos Santos Martins L, Dirkse B, Wehner S, Hanson R. Realization of a multinode quantum network of remote solid-state qubits. Science 2021; 372:259-264. [PMID: 33859028 DOI: 10.1126/science.abg1919] [Citation(s) in RCA: 83] [Impact Index Per Article: 27.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Accepted: 03/19/2021] [Indexed: 11/02/2022]
Abstract
The distribution of entangled states across the nodes of a future quantum internet will unlock fundamentally new technologies. Here, we report on the realization of a three-node entanglement-based quantum network. We combine remote quantum nodes based on diamond communication qubits into a scalable phase-stabilized architecture, supplemented with a robust memory qubit and local quantum logic. In addition, we achieve real-time communication and feed-forward gate operations across the network. We demonstrate two quantum network protocols without postselection: the distribution of genuine multipartite entangled states across the three nodes and entanglement swapping through an intermediary node. Our work establishes a key platform for exploring, testing, and developing multinode quantum network protocols and a quantum network control stack.
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Affiliation(s)
- M Pompili
- QuTech, Delft University of Technology, 2628 CJ Delft, Netherlands.,Kavli Institute of Nanoscience, Delft University of Technology, 2628 CJ Delft, Netherlands
| | - S L N Hermans
- QuTech, Delft University of Technology, 2628 CJ Delft, Netherlands.,Kavli Institute of Nanoscience, Delft University of Technology, 2628 CJ Delft, Netherlands
| | - S Baier
- QuTech, Delft University of Technology, 2628 CJ Delft, Netherlands.,Kavli Institute of Nanoscience, Delft University of Technology, 2628 CJ Delft, Netherlands
| | - H K C Beukers
- QuTech, Delft University of Technology, 2628 CJ Delft, Netherlands.,Kavli Institute of Nanoscience, Delft University of Technology, 2628 CJ Delft, Netherlands
| | - P C Humphreys
- QuTech, Delft University of Technology, 2628 CJ Delft, Netherlands.,Kavli Institute of Nanoscience, Delft University of Technology, 2628 CJ Delft, Netherlands
| | - R N Schouten
- QuTech, Delft University of Technology, 2628 CJ Delft, Netherlands.,Kavli Institute of Nanoscience, Delft University of Technology, 2628 CJ Delft, Netherlands
| | - R F L Vermeulen
- QuTech, Delft University of Technology, 2628 CJ Delft, Netherlands.,Kavli Institute of Nanoscience, Delft University of Technology, 2628 CJ Delft, Netherlands
| | - M J Tiggelman
- QuTech, Delft University of Technology, 2628 CJ Delft, Netherlands.,Kavli Institute of Nanoscience, Delft University of Technology, 2628 CJ Delft, Netherlands
| | - L Dos Santos Martins
- QuTech, Delft University of Technology, 2628 CJ Delft, Netherlands.,Kavli Institute of Nanoscience, Delft University of Technology, 2628 CJ Delft, Netherlands
| | - B Dirkse
- QuTech, Delft University of Technology, 2628 CJ Delft, Netherlands.,Kavli Institute of Nanoscience, Delft University of Technology, 2628 CJ Delft, Netherlands
| | - S Wehner
- QuTech, Delft University of Technology, 2628 CJ Delft, Netherlands.,Kavli Institute of Nanoscience, Delft University of Technology, 2628 CJ Delft, Netherlands
| | - R Hanson
- QuTech, Delft University of Technology, 2628 CJ Delft, Netherlands. .,Kavli Institute of Nanoscience, Delft University of Technology, 2628 CJ Delft, Netherlands
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23
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Gao S, Hughes WJ, Lucas DM, Ballance TG, Goodwin JF. An optically heated atomic source for compact ion trap vacuum systems. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2021; 92:033205. [PMID: 33820060 DOI: 10.1063/5.0038162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Accepted: 02/16/2021] [Indexed: 06/12/2023]
Abstract
We present a design for an atomic oven suitable for loading ion traps, which is operated via optical heating with a continuous-wave multimode diode laser. The absence of the low-resistance electrical connections necessary for Joule heating allows the oven to be extremely well thermally isolated from the rest of the vacuum system. Extrapolating from high-flux measurements of an oven filled with calcium, we calculate that a target region number density of 100 cm-3, suitable for rapid ion loading, will be produced with 175(10) mW of heating laser power, limited by radiative losses. With simple feedforward to the laser power, the turn-on time for the oven is 15 s. Our measurements indicate that an oven volume 1000 times smaller could still hold enough source metal for decades of continuous operation.
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Affiliation(s)
- S Gao
- Clarendon Laboratory, Department of Physics, University of Oxford, Parks Rd., Oxford OX1 3PU, United Kingdom
| | - W J Hughes
- Clarendon Laboratory, Department of Physics, University of Oxford, Parks Rd., Oxford OX1 3PU, United Kingdom
| | - D M Lucas
- Clarendon Laboratory, Department of Physics, University of Oxford, Parks Rd., Oxford OX1 3PU, United Kingdom
| | - T G Ballance
- ColdQuanta UK, Oxford Centre for Innovation, Oxford OX1 1BY, United Kingdom
| | - J F Goodwin
- Clarendon Laboratory, Department of Physics, University of Oxford, Parks Rd., Oxford OX1 3PU, United Kingdom
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24
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Kim J, Jeong J, Jung C, Lee M, Park Y, Dan Cho DI, Kim T. Observation of Hong-Ou-Mandel interference with scalable Yb +-photon interfaces. OPTICS EXPRESS 2020; 28:39727-39738. [PMID: 33379516 DOI: 10.1364/oe.409667] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Accepted: 12/08/2020] [Indexed: 06/12/2023]
Abstract
We present a compact optical design for a scalable trapped ion quantum processor employing a single high numerical aperture lens for the excitation of ions and collection of photons, both of which are essential for remote entanglement generation. We verified the design by performing a quantum interference experiment between two photons generated by two sets of the proposed design and observed a 82(3) % suppression of coincidence within 8.13 ns time window when the two photons became indistinguishable. This design can be extended for the simultaneous generation of multiple pairs of entangled qubits with existing fiber-array devices.
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25
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Araneda G, Cerchiari G, Higginbottom DB, Holz PC, Lakhmanskiy K, Obšil P, Colombe Y, Blatt R. The Panopticon device: An integrated Paul-trap-hemispherical mirror system for quantum optics. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2020; 91:113201. [PMID: 33261421 DOI: 10.1063/5.0020661] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Accepted: 10/15/2020] [Indexed: 06/12/2023]
Abstract
We present the design and construction of a new experimental apparatus for the trapping of single Ba+ ions in the center of curvature of an optical-quality hemispherical mirror. We describe the layout, fabrication, and integration of the full setup, consisting of a high-optical access monolithic "3D-printed" Paul trap, the hemispherical mirror, a diffraction-limited in-vacuum lens (NA = 0.7) for collection of atomic fluorescence, and a state-of-the art ultra-high vacuum vessel. This new apparatus enables the study of quantum electrodynamics effects such as strong inhibition and enhancement of spontaneous emission and achieves a collection efficiency of the emitted light in a single optical mode of 31%.
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Affiliation(s)
- G Araneda
- Institut für Experimentalphysik, Universität Innsbruck, Technikerstrasse 25, 6020 Innsbruck, Austria
| | - G Cerchiari
- Institut für Experimentalphysik, Universität Innsbruck, Technikerstrasse 25, 6020 Innsbruck, Austria
| | - D B Higginbottom
- Department of Physics, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - P C Holz
- Institut für Experimentalphysik, Universität Innsbruck, Technikerstrasse 25, 6020 Innsbruck, Austria
| | - K Lakhmanskiy
- Institut für Experimentalphysik, Universität Innsbruck, Technikerstrasse 25, 6020 Innsbruck, Austria
| | - P Obšil
- Department of Optics, Palacký University, 17. listopadu 12, 771 46 Olomouc, Czech Republic
| | - Y Colombe
- Institut für Experimentalphysik, Universität Innsbruck, Technikerstrasse 25, 6020 Innsbruck, Austria
| | - R Blatt
- Institut für Experimentalphysik, Universität Innsbruck, Technikerstrasse 25, 6020 Innsbruck, Austria
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Hughes AC, Schäfer VM, Thirumalai K, Nadlinger DP, Woodrow SR, Lucas DM, Ballance CJ. Benchmarking a High-Fidelity Mixed-Species Entangling Gate. PHYSICAL REVIEW LETTERS 2020; 125:080504. [PMID: 32909787 DOI: 10.1103/physrevlett.125.080504] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Accepted: 07/08/2020] [Indexed: 06/11/2023]
Abstract
We implement a two-qubit logic gate between a ^{43}Ca^{+} hyperfine qubit and a ^{88}Sr^{+} Zeeman qubit. For this pair of ion species, the S-P optical transitions are close enough that a single laser of wavelength 402 nm can be used to drive the gate but sufficiently well separated to give good spectral isolation and low photon scattering errors. We characterize the gate by full randomized benchmarking, gate set tomography, and Bell state analysis. The latter method gives a fidelity of 99.8(1)%, comparable to that of the best same-species gates and consistent with known sources of error.
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Affiliation(s)
- A C Hughes
- Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, United Kingdom
| | - V M Schäfer
- Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, United Kingdom
| | - K Thirumalai
- Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, United Kingdom
| | - D P Nadlinger
- Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, United Kingdom
| | - S R Woodrow
- Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, United Kingdom
| | - D M Lucas
- Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, United Kingdom
| | - C J Ballance
- Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, United Kingdom
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27
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Wright TA, Parry C, Gibson OR, Francis-Jones RJA, Mosley PJ. Resource-efficient frequency conversion for quantum networks via sequential four-wave mixing. OPTICS LETTERS 2020; 45:4587-4590. [PMID: 32797016 DOI: 10.1364/ol.398408] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Accepted: 07/10/2020] [Indexed: 06/11/2023]
Abstract
We report a resource-efficient scheme in which a single pump laser was used to achieve frequency conversion by Bragg-scattering four-wave mixing in a photonic crystal fiber. We demonstrate bidirectional conversion of coherent light between Sr+2P1/2→2D3/2 emission wavelength at 1092 nm and the telecommunication C band with conversion efficiencies of 4.2% and 37% for up- and down-conversion, respectively. We discuss how the scheme may be viably scaled to meet the temporal, spectral, and polarization stability requirements of a hybrid light-matter quantum network.
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28
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A Quantum Heat Exchanger for Nanotechnology. ENTROPY 2020; 22:e22040379. [PMID: 33286156 PMCID: PMC7516853 DOI: 10.3390/e22040379] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Revised: 03/17/2020] [Accepted: 03/21/2020] [Indexed: 11/17/2022]
Abstract
In this paper, we design a quantum heat exchanger which converts heat into light on relatively short quantum optical time scales. Our scheme takes advantage of heat transfer as well as collective cavity-mediated laser cooling of an atomic gas inside a cavitating bubble. Laser cooling routinely transfers individually trapped ions to nano-Kelvin temperatures for applications in quantum technology. The quantum heat exchanger which we propose here might be able to provide cooling rates of the order of Kelvin temperatures per millisecond and is expected to find applications in micro- and nanotechnology.
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