1
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Young AW, Geller S, Eckner WJ, Schine N, Glancy S, Knill E, Kaufman AM. An atomic boson sampler. Nature 2024; 629:311-316. [PMID: 38720040 DOI: 10.1038/s41586-024-07304-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Accepted: 03/13/2024] [Indexed: 05/12/2024]
Abstract
A boson sampler implements a restricted model of quantum computing. It is defined by the ability to sample from the distribution resulting from the interference of identical bosons propagating according to programmable, non-interacting dynamics1. An efficient exact classical simulation of boson sampling is not believed to exist, which has motivated ground-breaking boson sampling experiments in photonics with increasingly many photons2-12. However, it is difficult to generate and reliably evolve specific numbers of photons with low loss, and thus probabilistic techniques for postselection7 or marked changes to standard boson sampling10-12 are generally used. Here, we address the above challenges by implementing boson sampling using ultracold atoms13,14 in a two-dimensional, tunnel-coupled optical lattice. This demonstration is enabled by a previously unrealized combination of tools involving high-fidelity optical cooling and imaging of atoms in a lattice, as well as programmable control of those atoms using optical tweezers. When extended to interacting systems, our work demonstrates the core abilities required to directly assemble ground and excited states in simulations of various Hubbard models15,16.
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Affiliation(s)
- Aaron W Young
- JILA, University of Colorado and National Institute of Standards and Technology and Department of Physics, University of Colorado, Boulder, CO, USA.
| | - Shawn Geller
- National Institute of Standards and Technology, Boulder, CO, USA
- Department of Physics, University of Colorado, Boulder, CO, USA
| | - William J Eckner
- JILA, University of Colorado and National Institute of Standards and Technology and Department of Physics, University of Colorado, Boulder, CO, USA
| | - Nathan Schine
- JILA, University of Colorado and National Institute of Standards and Technology and Department of Physics, University of Colorado, Boulder, CO, USA
- Joint Quantum Institute, University of Maryland Department of Physics and National Institute of Standards and Technology, College Park, MD, USA
| | - Scott Glancy
- National Institute of Standards and Technology, Boulder, CO, USA
| | - Emanuel Knill
- National Institute of Standards and Technology, Boulder, CO, USA
- Center for Theory of Quantum Matter, University of Colorado, Boulder, CO, USA
| | - Adam M Kaufman
- JILA, University of Colorado and National Institute of Standards and Technology and Department of Physics, University of Colorado, Boulder, CO, USA.
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2
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Bohr EA, Kristensen SL, Hotter C, Schäffer SA, Robinson-Tait J, Thomsen JW, Zelevinsky T, Ritsch H, Müller JH. Collectively enhanced Ramsey readout by cavity sub- to superradiant transition. Nat Commun 2024; 15:1084. [PMID: 38316781 PMCID: PMC10844618 DOI: 10.1038/s41467-024-45420-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Accepted: 01/22/2024] [Indexed: 02/07/2024] Open
Abstract
When an inverted ensemble of atoms is tightly packed on the scale of its emission wavelength or when the atoms are collectively strongly coupled to a single cavity mode, their dipoles will align and decay rapidly via a superradiant burst. However, a spread-out dipole phase distribution theory predicts a required minimum threshold of atomic excitation for superradiance to occur. Here we experimentally confirm this predicted threshold for superradiant emission on a narrow optical transition when exciting the atoms transversely and show how to take advantage of the resulting sub- to superradiant transition. A π/2-pulse places the atoms in a subradiant state, protected from collective cavity decay, which we exploit during the free evolution period in a corresponding Ramsey pulse sequence. The final excited state population is read out via superradiant emission from the inverted atomic ensemble after a second π/2-pulse, and with minimal heating this allows for multiple Ramsey sequences within one experimental cycle. Our scheme is an innovative approach to atomic state readout characterized by its speed, simplicity, and highly directional emission of signal photons. It demonstrates the potential of sensors using collective effects in cavity-coupled quantum emitters.
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Affiliation(s)
- Eliot A Bohr
- Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, Copenhagen, DK-2100, Denmark.
| | - Sofus L Kristensen
- Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, Copenhagen, DK-2100, Denmark
| | - Christoph Hotter
- Institut für Theoretische Physik, Universität Innsbruck, Technikerstr. 21a, Innsbruck, A-6020, Austria
| | - Stefan A Schäffer
- Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, Copenhagen, DK-2100, Denmark
| | - Julian Robinson-Tait
- Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, Copenhagen, DK-2100, Denmark
| | - Jan W Thomsen
- Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, Copenhagen, DK-2100, Denmark
| | - Tanya Zelevinsky
- Department of Physics, Columbia University, 538 West 120th Street, New York, 10027-5255, NY, USA
| | - Helmut Ritsch
- Institut für Theoretische Physik, Universität Innsbruck, Technikerstr. 21a, Innsbruck, A-6020, Austria
| | - Jörg H Müller
- Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, Copenhagen, DK-2100, Denmark
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3
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Scholl P, Shaw AL, Tsai RBS, Finkelstein R, Choi J, Endres M. Erasure conversion in a high-fidelity Rydberg quantum simulator. Nature 2023; 622:273-278. [PMID: 37821592 PMCID: PMC10567575 DOI: 10.1038/s41586-023-06516-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Accepted: 08/03/2023] [Indexed: 10/13/2023]
Abstract
Minimizing and understanding errors is critical for quantum science, both in noisy intermediate scale quantum (NISQ) devices1 and for the quest towards fault-tolerant quantum computation2,3. Rydberg arrays have emerged as a prominent platform in this context4 with impressive system sizes5,6 and proposals suggesting how error-correction thresholds could be significantly improved by detecting leakage errors with single-atom resolution7,8, a form of erasure error conversion9-12. However, two-qubit entanglement fidelities in Rydberg atom arrays13,14 have lagged behind competitors15,16 and this type of erasure conversion is yet to be realized for matter-based qubits in general. Here we demonstrate both erasure conversion and high-fidelity Bell state generation using a Rydberg quantum simulator5,6,17,18. When excising data with erasure errors observed via fast imaging of alkaline-earth atoms19-22, we achieve a Bell state fidelity of [Formula: see text], which improves to [Formula: see text] when correcting for remaining state-preparation errors. We further apply erasure conversion in a quantum simulation experiment for quasi-adiabatic preparation of long-range order across a quantum phase transition, and reveal the otherwise hidden impact of these errors on the simulation outcome. Our work demonstrates the capability for Rydberg-based entanglement to reach fidelities in the 0.999 regime, with higher fidelities a question of technical improvements, and shows how erasure conversion can be utilized in NISQ devices. These techniques could be translated directly to quantum-error-correction codes with the addition of long-lived qubits7,22-24.
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Affiliation(s)
- Pascal Scholl
- California Institute of Technology, Pasadena, CA, USA
| | - Adam L Shaw
- California Institute of Technology, Pasadena, CA, USA
| | | | | | - Joonhee Choi
- California Institute of Technology, Pasadena, CA, USA
- Department of Electrical Engineering, Stanford University, Stanford, CA, USA
| | - Manuel Endres
- California Institute of Technology, Pasadena, CA, USA.
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4
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Blodgett KN, Peana D, Phatak SS, Terry LM, Montes MP, Hood JD. Imaging a ^{6}Li Atom in an Optical Tweezer 2000 Times with Λ-Enhanced Gray Molasses. PHYSICAL REVIEW LETTERS 2023; 131:083001. [PMID: 37683168 DOI: 10.1103/physrevlett.131.083001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Accepted: 07/31/2023] [Indexed: 09/10/2023]
Abstract
We have imaged lithium-6 thousands of times in an optical tweezer using Λ-enhanced gray molasses cooling light. Despite being the lightest alkali metal, with a recoil temperature of 3.5 μK, we achieve an imaging survival of 0.999 50(2), which sets the new benchmark for low-loss imaging of neutral atoms in optical tweezers. Lithium is loaded directly from a magneto-optical trap into a tweezer with an enhanced loading rate of 0.7. We cool the atom to 70 μK and present a new cooling model that accurately predicts steady-state temperature and scattering rate in the tweezer. These results pave the way for ground state preparation of lithium en route to the assembly of the LiCs molecule in its ground state.
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Affiliation(s)
- Karl N Blodgett
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, USA
| | - David Peana
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, USA
| | - Saumitra S Phatak
- Department of Physics and Astronomy, Purdue University, West Lafayette, Indiana 47907, USA
| | - Lane M Terry
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, USA
| | - Maria Paula Montes
- Department of Physics and Astronomy, Purdue University, West Lafayette, Indiana 47907, USA
| | - Jonathan D Hood
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, USA
- Department of Physics and Astronomy, Purdue University, West Lafayette, Indiana 47907, USA
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5
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Shaw AL, Scholl P, Finklestein R, Madjarov IS, Grinkemeyer B, Endres M. Dark-State Enhanced Loading of an Optical Tweezer Array. PHYSICAL REVIEW LETTERS 2023; 130:193402. [PMID: 37243641 DOI: 10.1103/physrevlett.130.193402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Accepted: 04/25/2023] [Indexed: 05/29/2023]
Abstract
Neutral atoms and molecules trapped in optical tweezers have become a prevalent resource for quantum simulation, computation, and metrology. However, the maximum achievable system sizes of such arrays are often limited by the stochastic nature of loading into optical tweezers, with a typical loading probability of only 50%. Here we present a species-agnostic method for dark-state enhanced loading (DSEL) based on real-time feedback, long-lived shelving states, and iterated array reloading. We demonstrate this technique with a 95-tweezer array of ^{88}Sr atoms, achieving a maximum loading probability of 84.02(4)% and a maximum array size of 91 atoms in one dimension. Our protocol is complementary to, and compatible with, existing schemes for enhanced loading based on direct control over light-assisted collisions, and we predict it can enable close-to-unity filling for arrays of atoms or molecules.
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Affiliation(s)
- Adam L Shaw
- Division of Physics, Mathematics and Astronomy, California Institute of Technology, Pasadena, California 91125, USA
| | - Pascal Scholl
- Division of Physics, Mathematics and Astronomy, California Institute of Technology, Pasadena, California 91125, USA
| | - Ran Finklestein
- Division of Physics, Mathematics and Astronomy, California Institute of Technology, Pasadena, California 91125, USA
| | - Ivaylo S Madjarov
- Division of Physics, Mathematics and Astronomy, California Institute of Technology, Pasadena, California 91125, USA
| | - Brandon Grinkemeyer
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Manuel Endres
- Division of Physics, Mathematics and Astronomy, California Institute of Technology, Pasadena, California 91125, USA
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6
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Choi J, Shaw AL, Madjarov IS, Xie X, Finkelstein R, Covey JP, Cotler JS, Mark DK, Huang HY, Kale A, Pichler H, Brandão FGSL, Choi S, Endres M. Preparing random states and benchmarking with many-body quantum chaos. Nature 2023; 613:468-473. [PMID: 36653567 DOI: 10.1038/s41586-022-05442-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Accepted: 10/13/2022] [Indexed: 01/19/2023]
Abstract
Producing quantum states at random has become increasingly important in modern quantum science, with applications being both theoretical and practical. In particular, ensembles of such randomly distributed, but pure, quantum states underlie our understanding of complexity in quantum circuits1 and black holes2, and have been used for benchmarking quantum devices3,4 in tests of quantum advantage5,6. However, creating random ensembles has necessitated a high degree of spatio-temporal control7-12 placing such studies out of reach for a wide class of quantum systems. Here we solve this problem by predicting and experimentally observing the emergence of random state ensembles naturally under time-independent Hamiltonian dynamics, which we use to implement an efficient, widely applicable benchmarking protocol. The observed random ensembles emerge from projective measurements and are intimately linked to universal correlations built up between subsystems of a larger quantum system, offering new insights into quantum thermalization13. Predicated on this discovery, we develop a fidelity estimation scheme, which we demonstrate for a Rydberg quantum simulator with up to 25 atoms using fewer than 104 experimental samples. This method has broad applicability, as we demonstrate for Hamiltonian parameter estimation, target-state generation benchmarking, and comparison of analogue and digital quantum devices. Our work has implications for understanding randomness in quantum dynamics14 and enables applications of this concept in a much wider context4,5,9,10,15-20.
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Affiliation(s)
- Joonhee Choi
- California Institute of Technology, Pasadena, CA, USA
| | - Adam L Shaw
- California Institute of Technology, Pasadena, CA, USA
| | | | - Xin Xie
- California Institute of Technology, Pasadena, CA, USA
| | | | - Jacob P Covey
- California Institute of Technology, Pasadena, CA, USA.,Department of Physics, The University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | | | - Daniel K Mark
- Center for Theoretical Physics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | | | | | - Hannes Pichler
- Institute for Theoretical Physics, University of Innsbruck, Innsbruck, Austria.,Institute for Quantum Optics and Quantum Information, Austrian Academy of Sciences, Innsbruck, Austria
| | | | - Soonwon Choi
- Center for Theoretical Physics, Massachusetts Institute of Technology, Cambridge, MA, USA. .,Department of Physics, University of California, Berkeley, CA, USA.
| | - Manuel Endres
- California Institute of Technology, Pasadena, CA, USA.
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7
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Deist E, Lu YH, Ho J, Pasha MK, Zeiher J, Yan Z, Stamper-Kurn DM. Mid-Circuit Cavity Measurement in a Neutral Atom Array. PHYSICAL REVIEW LETTERS 2022; 129:203602. [PMID: 36462020 DOI: 10.1103/physrevlett.129.203602] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 08/19/2022] [Accepted: 10/05/2022] [Indexed: 06/17/2023]
Abstract
Subsystem readout during a quantum process, or mid-circuit measurement, is crucial for error correction in quantum computation, simulation, and metrology. Ideal mid-circuit measurement should be faster than the decoherence of the system, high-fidelity, and nondestructive to the unmeasured qubits. Here, we use a strongly coupled optical cavity to read out the state of a single tweezer-trapped ^{87}Rb atom within a small tweezer array. Measuring either atomic fluorescence or the transmission of light through the cavity, we detect both the presence and the state of an atom in the tweezer, within only tens of microseconds, with state preparation and measurement infidelities of roughly 0.5% and atom loss probabilities of around 1%. Using a two-tweezer system, we find measurement on one atom within the cavity causes no observable hyperfine-state decoherence on a second atom located tens of microns from the cavity volume. This high-fidelity mid-circuit readout method is a substantial step toward quantum error correction in neutral atom arrays.
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Affiliation(s)
- Emma Deist
- Department of Physics, University of California, Berkeley, California 94720, USA
- Challenge Institute for Quantum Computation, University of California, Berkeley, California 94720, USA
| | - Yue-Hui Lu
- Department of Physics, University of California, Berkeley, California 94720, USA
- Challenge Institute for Quantum Computation, University of California, Berkeley, California 94720, USA
| | - Jacquelyn Ho
- Department of Physics, University of California, Berkeley, California 94720, USA
- Challenge Institute for Quantum Computation, University of California, Berkeley, California 94720, USA
| | - Mary Kate Pasha
- Department of Physics, University of California, Berkeley, California 94720, USA
- Challenge Institute for Quantum Computation, University of California, Berkeley, California 94720, USA
| | - Johannes Zeiher
- Department of Physics, University of California, Berkeley, California 94720, USA
- Max-Planck-Institut für Quantenoptik, 85748 Garching, Germany
- Munich Center for Quantum Science and Technology (MCQST), 80799 Munich, Germany
| | - Zhenjie Yan
- Department of Physics, University of California, Berkeley, California 94720, USA
- Challenge Institute for Quantum Computation, University of California, Berkeley, California 94720, USA
| | - Dan M Stamper-Kurn
- Department of Physics, University of California, Berkeley, California 94720, USA
- Challenge Institute for Quantum Computation, University of California, Berkeley, California 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
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8
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Zhang X, Beloy K, Hassan YS, McGrew WF, Chen CC, Siegel JL, Grogan T, Ludlow AD. Subrecoil Clock-Transition Laser Cooling Enabling Shallow Optical Lattice Clocks. PHYSICAL REVIEW LETTERS 2022; 129:113202. [PMID: 36154423 DOI: 10.1103/physrevlett.129.113202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Accepted: 07/19/2022] [Indexed: 06/16/2023]
Abstract
Laser cooling is a key ingredient for quantum control of atomic systems in a variety of settings. In divalent atoms, two-stage Doppler cooling is typically used to bring atoms to the μK regime. Here, we implement a pulsed radial cooling scheme using the ultranarrow ^{1}S_{0}-^{3}P_{0} clock transition in ytterbium to realize subrecoil temperatures, down to tens of nK. Together with sideband cooling along the one-dimensional lattice axis, we efficiently prepare atoms in shallow lattices at an energy of 6 lattice recoils. Under these conditions key limits on lattice clock accuracy and instability are reduced, opening the door to dramatic improvements. Furthermore, tunneling shifts in the shallow lattice do not compromise clock accuracy at the 10^{-19} level.
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Affiliation(s)
- X Zhang
- National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA
- University of Colorado, Department of Physics, Boulder, Colorado 80309, USA
| | - K Beloy
- National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA
| | - Y S Hassan
- National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA
- University of Colorado, Department of Physics, Boulder, Colorado 80309, USA
| | - W F McGrew
- National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA
- University of Colorado, Department of Physics, Boulder, Colorado 80309, USA
| | - C-C Chen
- National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA
- University of Colorado, Department of Physics, Boulder, Colorado 80309, USA
| | - J L Siegel
- National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA
- University of Colorado, Department of Physics, Boulder, Colorado 80309, USA
| | - T Grogan
- National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA
- University of Colorado, Department of Physics, Boulder, Colorado 80309, USA
| | - A D Ludlow
- National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA
- University of Colorado, Department of Physics, Boulder, Colorado 80309, USA
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9
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Young AW, Eckner WJ, Schine N, Childs AM, Kaufman AM. Tweezer-programmable 2D quantum walks in a Hubbard-regime lattice. Science 2022; 377:885-889. [PMID: 35981010 DOI: 10.1126/science.abo0608] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Quantum walks provide a framework for designing quantum algorithms that is both intuitive and universal. To leverage the computational power of these walks, it is important to be able to programmably modify the graph a walker traverses while maintaining coherence. We do this by combining the fast, programmable control provided by optical tweezers with the scalable, homogeneous environment of an optical lattice. With these tools we study continuous-time quantum walks of single atoms on a square lattice and perform proof-of-principle demonstrations of spatial search with these walks. When scaled to more particles, the capabilities demonstrated can be extended to study a variety of problems in quantum information science, including performing more effective versions of spatial search using a larger graph with increased connectivity.
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Affiliation(s)
- Aaron W Young
- JILA, University of Colorado and National Institute of Standards and Technology, and Department of Physics, University of Colorado, Boulder, CO 80309, USA
| | - William J Eckner
- JILA, University of Colorado and National Institute of Standards and Technology, and Department of Physics, University of Colorado, Boulder, CO 80309, USA
| | - Nathan Schine
- JILA, University of Colorado and National Institute of Standards and Technology, and Department of Physics, University of Colorado, Boulder, CO 80309, USA
| | - Andrew M Childs
- Department of Computer Science, University of Maryland, College Park, MD 20742, USA.,Institute for Advanced Computer Studies and Joint Center for Quantum Information and Computer Science, University of Maryland, College Park, MD 20742, USA
| | - Adam M Kaufman
- JILA, University of Colorado and National Institute of Standards and Technology, and Department of Physics, University of Colorado, Boulder, CO 80309, USA
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10
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Assembly and coherent control of a register of nuclear spin qubits. Nat Commun 2022; 13:2779. [PMID: 35589685 PMCID: PMC9120523 DOI: 10.1038/s41467-022-29977-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Accepted: 04/08/2022] [Indexed: 12/01/2022] Open
Abstract
The generation of a register of highly coherent, but independent, qubits is a prerequisite to performing universal quantum computation. Here we introduce a qubit encoded in two nuclear spin states of a single 87Sr atom and demonstrate coherence approaching the minute-scale within an assembled register of individually-controlled qubits. While other systems have shown impressive coherence times through some combination of shielding, careful trapping, global operations, and dynamical decoupling, we achieve comparable coherence times while individually driving multiple qubits in parallel. We highlight that even with simultaneous manipulation of multiple qubits within the register, we observe coherence in excess of 105 times the current length of the operations, with \documentclass[12pt]{minimal}
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\begin{document}$${T}_{2}^{{{{{\mathrm{echo}}}}}}=\left(40\pm 7\right)$$\end{document}T2echo=40±7 seconds. We anticipate that nuclear spin qubits will combine readily with the technical advances that have led to larger arrays of individually trapped neutral atoms and high-fidelity entangling operations, thus accelerating the realization of intermediate-scale quantum information processors. In large qubit registers, long coherence times and individual qubit control are difficult to achieve at the same time. Here, the authors assemble a 2D register of qubits in an array of fermionic alkaline-earth atoms, where tailored pulses can be applied to subsets of individual qubits in parallel.
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11
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Fernández-Fernández D, González-Tudela A. Tunable Directional Emission and Collective Dissipation with Quantum Metasurfaces. PHYSICAL REVIEW LETTERS 2022; 128:113601. [PMID: 35363033 DOI: 10.1103/physrevlett.128.113601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Accepted: 01/26/2022] [Indexed: 06/14/2023]
Abstract
Subwavelength atomic arrays, recently labeled as quantum metamaterials, have emerged as an exciting platform for obtaining novel quantum optical phenomena. The strong interference effects in these systems generate subradiant excitations that propagate through the atomic array with very long lifetimes. Here, we demonstrate that one can harness these excitations to obtain tunable directional emission patterns and collective dissipative couplings when placing judiciously additional atoms nearby the atomic array. For doing that, we first characterize the optimal square array geometry to obtain directional emission patterns. Then, we characterize the best atomic positions to couple efficiently to the subradiant metasurface excitations and provide several improvement strategies based on entangled atomic clusters or bilayers. Afterward, we also show how the directionality of the emission pattern can be controlled through the relative dipole orientation between the auxiliary atoms and the one of the array. Finally, we benchmark how these directional emission patterns translate into to collective, anisotropic dissipative couplings between the auxiliary atoms by studying the lifetime modification of atomic entangled states.
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Affiliation(s)
- D Fernández-Fernández
- Institute of Fundamental Physics IFF-CSIC, Calle Serrano 113b, 28006 Madrid, Spain
- Instituto de Ciencia de Materiales de Madrid ICMM-CSIC, 28049 Madrid, Spain
| | - A González-Tudela
- Institute of Fundamental Physics IFF-CSIC, Calle Serrano 113b, 28006 Madrid, Spain
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12
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Afek G, Carney D, Moore DC. Coherent Scattering of Low Mass Dark Matter from Optically Trapped Sensors. PHYSICAL REVIEW LETTERS 2022; 128:101301. [PMID: 35333080 DOI: 10.1103/physrevlett.128.101301] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Accepted: 01/21/2022] [Indexed: 06/14/2023]
Abstract
We propose a search for low mass dark matter particles through momentum recoils caused by their scattering from trapped, nanometer-scale objects. Our projections show that even with a modest array of femtogram-mass sensors, parameter space beyond the reach of existing experiments can be explored. The case of smaller, attogram-mass sensors is also analyzed-where dark matter can coherently scatter from the entire sensor-enabling a large enhancement in the scattering cross-section relative to interactions with single nuclei. Large arrays of such sensors have the potential to investigate new parameter space down to dark matter masses as low as 10 keV. If recoils from dark matter are detected by such sensors, their inherent directional sensitivity would allow an unambiguous identification of a dark matter signal.
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Affiliation(s)
- Gadi Afek
- Wright Laboratory, Department of Physics, Yale University, New Haven, Connecticut 06520, USA
| | - Daniel Carney
- Physics Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - David C Moore
- Wright Laboratory, Department of Physics, Yale University, New Haven, Connecticut 06520, USA
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13
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Bhatt RP, Kilinc J, Höcker L, Jendrzejewski F. Stochastic dynamics of a few sodium atoms in presence of a cold potassium cloud. Sci Rep 2022; 12:2422. [PMID: 35165302 PMCID: PMC8844084 DOI: 10.1038/s41598-022-05778-8] [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: 09/22/2021] [Accepted: 01/14/2022] [Indexed: 11/15/2022] Open
Abstract
Single particle resolution is a requirement for numerous experimental protocols that emulate the dynamics of small systems in a bath. Here, we accurately resolve through atom counting the stochastic dynamics of a few sodium atoms in presence of a cold potassium cloud. This capability enables us to rule out the effect of inter-species interaction on sodium atom number dynamics, at very low atomic densities present in these experiments. We study the noise sources for sodium and potassium in a common framework. Thereby, we assign the detection limits to 4.3 atoms for potassium and 0.2 atoms (corresponding to 96% fidelity) for sodium. This opens possibilities for future experiments with a few atoms immersed in a quantum degenerate gas.
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14
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Langenfeld S, Thomas P, Morin O, Rempe G. Quantum Repeater Node Demonstrating Unconditionally Secure Key Distribution. PHYSICAL REVIEW LETTERS 2021; 126:230506. [PMID: 34170169 DOI: 10.1103/physrevlett.126.230506] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Accepted: 05/13/2021] [Indexed: 06/13/2023]
Abstract
Long-distance quantum communication requires quantum repeaters to overcome photon loss in optical fibers. Here we demonstrate a repeater node with two memory atoms in an optical cavity. Both atoms are individually and repeatedly entangled with photons that are distributed until each communication partner has independently received one of them. An atomic Bell-state measurement followed by classical communication serves to establish a key. We demonstrate scaling advantage of the key rate, increase the effective attenuation length by a factor of 2, and beat the error-rate threshold of 11% for unconditionally secure communication, the corner stones for repeater-based quantum networks.
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Affiliation(s)
- S Langenfeld
- Max-Planck-Institut für Quantenoptik, Hans-Kopfermann-Strasse 1, 85748 Garching, Germany
| | - P Thomas
- Max-Planck-Institut für Quantenoptik, Hans-Kopfermann-Strasse 1, 85748 Garching, Germany
| | - O Morin
- Max-Planck-Institut für Quantenoptik, Hans-Kopfermann-Strasse 1, 85748 Garching, Germany
| | - G Rempe
- Max-Planck-Institut für Quantenoptik, Hans-Kopfermann-Strasse 1, 85748 Garching, Germany
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16
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Half-minute-scale atomic coherence and high relative stability in a tweezer clock. Nature 2020; 588:408-413. [PMID: 33328666 DOI: 10.1038/s41586-020-3009-y] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Accepted: 09/17/2020] [Indexed: 11/09/2022]
Abstract
The preparation of large, low-entropy, highly coherent ensembles of identical quantum systems is fundamental for many studies in quantum metrology1, simulation2 and information3. However, the simultaneous realization of these properties remains a central challenge in quantum science across atomic and condensed-matter systems2,4-7. Here we leverage the favourable properties of tweezer-trapped alkaline-earth (strontium-88) atoms8-10, and introduce a hybrid approach to tailoring optical potentials that balances scalability, high-fidelity state preparation, site-resolved readout and preservation of atomic coherence. With this approach, we achieve trapping and optical-clock excited-state lifetimes exceeding 40 seconds in ensembles of approximately 150 atoms. This leads to half-minute-scale atomic coherence on an optical-clock transition, corresponding to quality factors well in excess of 1016. These coherence times and atom numbers reduce the effect of quantum projection noise to a level that is comparable with that of leading atomic systems, which use optical lattices to interrogate many thousands of atoms in parallel11,12. The result is a relative fractional frequency stability of 5.2(3) × 10-17τ-1/2 (where τ is the averaging time in seconds) for synchronous clock comparisons between sub-ensembles within the tweezer array. When further combined with the microscopic control and readout that are available in this system, these results pave the way towards long-lived engineered entanglement on an optical-clock transition13 in tailored atom arrays.
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17
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He X, Wang K, Zhuang J, Xu P, Gao X, Guo R, Sheng C, Liu M, Wang J, Li J, Shlyapnikov GV, Zhan M. Coherently forming a single molecule in an optical trap. Science 2020; 370:331-335. [PMID: 32972992 DOI: 10.1126/science.aba7468] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2020] [Accepted: 08/27/2020] [Indexed: 11/02/2022]
Abstract
Ultracold single molecules have wide-ranging potential applications, such as ultracold chemistry, precision measurements, quantum simulation, and quantum computation. However, given the difficulty of achieving full control of a complex atom-molecule system, the coherent formation of single molecules remains a challenge. Here, we report an alternative route to coherently bind two atoms into a weakly bound molecule at megahertz levels by coupling atomic spins to their two-body relative motion in a strongly focused laser with inherent polarization gradients. The coherent nature is demonstrated by long-lived atom-molecule Rabi oscillations. We further manipulate the motional levels of the molecules and measure the binding energy precisely. This work opens the door to full control of all degrees of freedom in atom-molecule systems.
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Affiliation(s)
- Xiaodong He
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, APM, Chinese Academy of Sciences, Wuhan 430071, China. .,Center for Cold Atom Physics, Chinese Academy of Sciences, Wuhan 430071, China
| | - Kunpeng Wang
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, APM, Chinese Academy of Sciences, Wuhan 430071, China.,Center for Cold Atom Physics, Chinese Academy of Sciences, Wuhan 430071, China.,School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jun Zhuang
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, APM, Chinese Academy of Sciences, Wuhan 430071, China.,Center for Cold Atom Physics, Chinese Academy of Sciences, Wuhan 430071, China.,School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Peng Xu
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, APM, Chinese Academy of Sciences, Wuhan 430071, China.,Center for Cold Atom Physics, Chinese Academy of Sciences, Wuhan 430071, China
| | - Xiang Gao
- Institute for Theoretical Physics, Vienna University of Technology, A-1040 Vienna, Austria.,Beijing Computational Science Research Center, Beijing 100193, China
| | - Ruijun Guo
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, APM, Chinese Academy of Sciences, Wuhan 430071, China.,Center for Cold Atom Physics, Chinese Academy of Sciences, Wuhan 430071, China.,School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Cheng Sheng
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, APM, Chinese Academy of Sciences, Wuhan 430071, China.,Center for Cold Atom Physics, Chinese Academy of Sciences, Wuhan 430071, China
| | - Min Liu
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, APM, Chinese Academy of Sciences, Wuhan 430071, China.,Center for Cold Atom Physics, Chinese Academy of Sciences, Wuhan 430071, China
| | - Jin Wang
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, APM, Chinese Academy of Sciences, Wuhan 430071, China.,Center for Cold Atom Physics, Chinese Academy of Sciences, Wuhan 430071, China
| | - Jiaming Li
- Department of Physics and Center for Atomic and Molecular Nanosciences, Tsinghua University, Beijing 100084, China.,Key Laboratory for Laser Plasmas (Ministry of Education), and Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China.,Collaborative Innovation Center of Quantum Matter, Beijing 100084, China
| | - G V Shlyapnikov
- LPTMS, CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91405 Orsay, France.,Russian Quantum Center, Skolkovo, Moscow 121025, Russia.,Van der Waals-Zeeman Institute, Institute of Physics, University of Amsterdam, 1098 XH Amsterdam, Netherlands
| | - Mingsheng Zhan
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, APM, Chinese Academy of Sciences, Wuhan 430071, China. .,Center for Cold Atom Physics, Chinese Academy of Sciences, Wuhan 430071, China
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18
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Knottnerus IHA, Pyatchenkov S, Onishchenko O, Urech A, Schreck F, Siviloglou GA. Microscope objective for imaging atomic strontium with 0.63 micrometer resolution. OPTICS EXPRESS 2020; 28:11106-11116. [PMID: 32403628 DOI: 10.1364/oe.388809] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Accepted: 03/17/2020] [Indexed: 06/11/2023]
Abstract
Imaging and manipulating individual atoms with submicrometer separation can be instrumental for quantum simulation of condensed matter Hamiltonians and quantum computation with neutral atoms. Here we present an open-source design of a microscope objective for atomic strontium, consisting solely of off-the-shelf lenses, that is diffraction-limited for 461 nm light. A prototype built with a simple stacking design is measured to have a resolution of 0.63(4) µm, which is in agreement with the predicted value. This performance, together with the near diffraction-limited performance for 532 nm light, makes this design useful for both quantum gas microscopes and optical tweezer experiments with strontium. Our microscope can easily be adapted to experiments with other atomic species such as erbium, ytterbium, and dysprosium, as with rubidium Rydberg atoms.
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19
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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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20
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Levine H, Keesling A, Semeghini G, Omran A, Wang TT, Ebadi S, Bernien H, Greiner M, Vuletić V, Pichler H, Lukin MD. Parallel Implementation of High-Fidelity Multiqubit Gates with Neutral Atoms. PHYSICAL REVIEW LETTERS 2019; 123:170503. [PMID: 31702233 DOI: 10.1103/physrevlett.123.170503] [Citation(s) in RCA: 64] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Indexed: 06/10/2023]
Abstract
We report the implementation of universal two- and three-qubit entangling gates on neutral-atom qubits encoded in long-lived hyperfine ground states. The gates are mediated by excitation to strongly interacting Rydberg states and are implemented in parallel on several clusters of atoms in a one-dimensional array of optical tweezers. Specifically, we realize the controlled-phase gate, enacted by a novel, fast protocol involving only global coupling of two qubits to Rydberg states. We benchmark this operation by preparing Bell states with fidelity F≥95.0(2)%, and extract gate fidelity ≥97.4(3)%, averaged across five atom pairs. In addition, we report a proof-of-principle implementation of the three-qubit Toffoli gate, in which two control atoms simultaneously constrain the behavior of one target atom. These experiments demonstrate key ingredients for high-fidelity quantum information processing in a scalable neutral-atom platform.
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Affiliation(s)
- Harry Levine
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Alexander Keesling
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Giulia Semeghini
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Ahmed Omran
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Tout T Wang
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
- Department of Physics, Gordon College, Wenham, Massachusetts 01984, USA
| | - Sepehr Ebadi
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Hannes Bernien
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, Illinois 60637, USA
| | - Markus Greiner
- 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
| | - Hannes Pichler
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
- ITAMP, Harvard-Smithsonian Center for Astrophysics, Cambridge, Massachusetts 02138, USA
| | - Mikhail D Lukin
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
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21
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Norcia MA, Young AW, Eckner WJ, Oelker E, Ye J, Kaufman AM. Seconds-scale coherence on an optical clock transition in a tweezer array. Science 2019; 366:93-97. [PMID: 31515245 DOI: 10.1126/science.aay0644] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Accepted: 09/03/2019] [Indexed: 11/03/2022]
Abstract
Coherent control of high-quality factor optical transitions in atoms has revolutionized precision frequency metrology. Leading optical atomic clocks rely on the interrogation of such transitions in either single ions or ensembles of neutral atoms to stabilize a laser frequency at high precision and accuracy. We demonstrate a platform that combines the key strengths of these two approaches, based on arrays of individual strontium atoms held within optical tweezers. We report coherence times of 3.4 seconds, single-ensemble duty cycles up to 96% through repeated interrogation, and frequency stability of 4.7 × 10-16 (τ/s)-1/2 These results establish optical tweezer arrays as a powerful tool for coherent control of optical transitions for metrology and quantum information science.
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Affiliation(s)
- Matthew A Norcia
- JILA, University of Colorado and National Institute of Standards and Technology, and Department of Physics, University of Colorado, Boulder, CO 80309, USA
| | - Aaron W Young
- JILA, University of Colorado and National Institute of Standards and Technology, and Department of Physics, University of Colorado, Boulder, CO 80309, USA
| | - William J Eckner
- JILA, University of Colorado and National Institute of Standards and Technology, and Department of Physics, University of Colorado, Boulder, CO 80309, USA
| | - Eric Oelker
- JILA, University of Colorado and National Institute of Standards and Technology, and Department of Physics, University of Colorado, Boulder, CO 80309, USA
| | - Jun Ye
- JILA, University of Colorado and National Institute of Standards and Technology, and Department of Physics, University of Colorado, Boulder, CO 80309, USA
| | - Adam M Kaufman
- JILA, University of Colorado and National Institute of Standards and Technology, and Department of Physics, University of Colorado, Boulder, CO 80309, USA.
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