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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: 2] [Impact Index Per Article: 2.0] [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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Yan Z, Ho J, Lu YH, Masson SJ, Asenjo-Garcia A, Stamper-Kurn DM. Superradiant and Subradiant Cavity Scattering by Atom Arrays. PHYSICAL REVIEW LETTERS 2023; 131:253603. [PMID: 38181363 DOI: 10.1103/physrevlett.131.253603] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Accepted: 11/02/2023] [Indexed: 01/07/2024]
Abstract
We realize collective enhancement and suppression of light scattered by an array of tweezer-trapped ^{87}Rb atoms positioned within a strongly coupled Fabry-Pérot optical cavity. We illuminate the array with light directed transverse to the cavity axis, in the low saturation regime, and detect photons scattered into the cavity. For an array with integer-optical-wavelength spacing each atom scatters light into the cavity with nearly identical scattering amplitude, leading to an observed N^{2} scaling of cavity photon number as the atom number increases stepwise from N=1 to N=8. By contrast, for an array with half-integer-wavelength spacing, destructive interference of scattering amplitudes yields a nonmonotonic, subradiant cavity intensity versus N. By analyzing the polarization of light emitted from the cavity, we find that Rayleigh scattering can be collectively enhanced or suppressed with respect to Raman scattering. We observe also that atom-induced shifts and broadenings of the cavity resonance are precisely tuned by varying the atom number and positions. Altogether, tweezer arrays provide exquisite control of atomic cavity QED spanning from the single- to the many-body regime.
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Affiliation(s)
- Zhenjie Yan
- 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
| | - 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
| | - Stuart J Masson
- Department of Physics, Columbia University, New York, New York 10027, USA
| | - Ana Asenjo-Garcia
- Department of Physics, Columbia University, New York, New York 10027, 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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Nie W, Shi T, Liu YX, Nori F. Non-Hermitian Waveguide Cavity QED with Tunable Atomic Mirrors. PHYSICAL REVIEW LETTERS 2023; 131:103602. [PMID: 37739354 DOI: 10.1103/physrevlett.131.103602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Accepted: 07/25/2023] [Indexed: 09/24/2023]
Abstract
Optical mirrors determine cavity properties by means of light reflection. Imperfect reflection gives rise to open cavities with photon loss. We study an open cavity made of atom-dimer mirrors with a tunable reflection spectrum. We find that the atomic cavity shows anti-PT symmetry. The anti-PT phase transition controlled by atomic couplings in mirrors indicates the emergence of two degenerate cavity supermodes. Interestingly, a threshold of mirror reflection is identified for realizing strong coherent cavity-atom coupling. This reflection threshold reveals the criterion of atomic mirrors to produce a good cavity. Moreover, cavity quantum electrodynamics with a probe atom shows mirror-tuned properties, including reflection-dependent polaritons formed by the cavity and probe atom. Our Letter presents a non-Hermitian theory of an anti-PT atomic cavity, which may have applications in quantum optics and quantum computation.
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Affiliation(s)
- Wei Nie
- Center for Joint Quantum Studies and Department of Physics, School of Science, Tianjin University, Tianjin 300350, China
| | - Tao Shi
- Institute of Theoretical Physics, Chinese Academy of Sciences, P.O. Box 2735, Beijing 100190, China
- CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yu-Xi Liu
- School of Integrated Circuits, Tsinghua University, Beijing 100084, China
| | - Franco Nori
- Theoretical Quantum Physics Laboratory, Cluster for Pioneering Research, RIKEN, Wakoshi, Saitama 351-0198, Japan
- Center for Quantum Computing, RIKEN, Wakoshi, Saitama 351-0198, Japan
- Physics Department, The University of Michigan, Ann Arbor, Michigan 48109-1040, USA
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Ke Y, Huang J, Liu W, Kivshar Y, Lee C. Topological Inverse Band Theory in Waveguide Quantum Electrodynamics. PHYSICAL REVIEW LETTERS 2023; 131:103604. [PMID: 37739358 DOI: 10.1103/physrevlett.131.103604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Accepted: 08/21/2023] [Indexed: 09/24/2023]
Abstract
Topological phases play a crucial role in the fundamental physics of light-matter interaction and emerging applications of quantum technologies. However, the topological band theory of waveguide QED systems is known to break down, because the energy bands become disconnected. Here, we introduce a concept of the inverse energy band and explore analytically topological scattering in a waveguide with an array of quantum emitters. We uncover a rich structure of topological phase transitions, symmetric scale-free localization, completely flat bands, and the corresponding dark Wannier states. Although bulk-edge correspondence is partially broken because of radiative decay, we prove analytically that the scale-free localized states are distributed in a single inverse energy band in the topological phase and in two inverse bands in the trivial phase. Surprisingly, the winding number of the scattering textures depends on both the topological phase of inverse subradiant band and the odevity of the cell number. Our Letter uncovers the field of the topological inverse bands, and it brings a novel vision to topological phases in light-matter interactions.
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Affiliation(s)
- Yongguan Ke
- Institute of Quantum Precision Measurement, State Key Laboratory of Radio Frequency Heterogeneous Integration, Shenzhen University, Shenzhen 518060, China
- College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China
- Laboratory of Quantum Engineering and Quantum Metrology, School of Physics and Astronomy, Sun Yat-Sen University (Zhuhai Campus), Zhuhai 519082, China
| | - Jiaxuan Huang
- Laboratory of Quantum Engineering and Quantum Metrology, School of Physics and Astronomy, Sun Yat-Sen University (Zhuhai Campus), Zhuhai 519082, China
| | - Wenjie Liu
- Laboratory of Quantum Engineering and Quantum Metrology, School of Physics and Astronomy, Sun Yat-Sen University (Zhuhai Campus), Zhuhai 519082, China
- Quantum Science Center of Guangdong-Hongkong-Macao Greater Bay Area (Guangdong), Shenzhen 518045, China
| | - Yuri Kivshar
- Nonlinear Physics Center, Research School of Physics, Australian National University, Canberra, Australian Capital Territory 2601, Australia
- Qingdao Innovation and Development Center, Harbin Engineering University, Qingdao 266000, China
| | - Chaohong Lee
- Institute of Quantum Precision Measurement, State Key Laboratory of Radio Frequency Heterogeneous Integration, Shenzhen University, Shenzhen 518060, China
- College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China
- Quantum Science Center of Guangdong-Hongkong-Macao Greater Bay Area (Guangdong), Shenzhen 518045, China
- Nonlinear Physics Center, Research School of Physics, Australian National University, Canberra, Australian Capital Territory 2601, Australia
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