1
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Hutson RB, Milner WR, Yan L, Ye J, Sanner C. Observation of millihertz-level cooperative Lamb shifts in an optical atomic clock. Science 2024; 383:384-387. [PMID: 38271496 DOI: 10.1126/science.adh4477] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Accepted: 12/15/2023] [Indexed: 01/27/2024]
Abstract
Collective couplings of atomic dipoles to a shared electromagnetic environment produce a wide range of many-body phenomena. We report on the direct observation of resonant electric dipole-dipole interactions in a cubic array of atoms in the many-excitation limit. The interactions produce spatially dependent cooperative Lamb shifts when spectroscopically interrogating the millihertz-wide optical clock transition in strontium-87. We show that the ensemble-averaged shifts can be suppressed below the level of evaluated systematic uncertainties for optical atomic clocks. Additionally, we demonstrate that excitation of the atomic dipoles near a Bragg angle can enhance these effects by nearly an order of magnitude compared with nonresonant geometries. Our work demonstrates a platform for precise studies of the quantum many-body physics of spins with long-range interactions mediated by propagating photons.
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Affiliation(s)
- Ross B Hutson
- JILA, NIST, and University of Colorado, Boulder, CO 80309, USA
- Department of Physics, University of Colorado, Boulder, CO 80309, USA
| | - William R Milner
- JILA, NIST, and University of Colorado, Boulder, CO 80309, USA
- Department of Physics, University of Colorado, Boulder, CO 80309, USA
| | - Lingfeng Yan
- JILA, NIST, and University of Colorado, Boulder, CO 80309, USA
- Department of Physics, University of Colorado, Boulder, CO 80309, USA
| | - Jun Ye
- JILA, NIST, and University of Colorado, Boulder, CO 80309, USA
- Department of Physics, University of Colorado, Boulder, CO 80309, USA
| | - Christian Sanner
- Department of Physics, Colorado State University, Fort Collins, CO 80523, USA
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2
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Wang ZB, Gu C, Hu XX, Zhang YT, Zhang JZ, Li G, He XD, Zou XB, Dong CH, Guo GC, Zou CL. Controllable atomic collision in a tight optical dipole trap. OPTICS LETTERS 2023; 48:1064-1067. [PMID: 36791011 DOI: 10.1364/ol.479036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2022] [Accepted: 01/12/2023] [Indexed: 06/18/2023]
Abstract
Single atoms are interesting candidates for studying quantum optics and quantum information processing. Recently, trapping and manipulation of single atoms using tight optical dipole traps has generated considerable interest. Here we report an experimental investigation of the dynamics of atoms in a modified optical dipole trap with a backward propagating dipole trap beam, where a change in the two-atom collision rate by six times has been achieved. The theoretical model presented gives a prediction of high probabilities of few-atom loading rates under proper experimental conditions. This work provides an alternative approach to the control of the few-atom dynamics in a dipole trap and the study of the collective quantum optical effects of a few atoms.
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3
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Masson SJ, Asenjo-Garcia A. Universality of Dicke superradiance in arrays of quantum emitters. Nat Commun 2022; 13:2285. [PMID: 35477714 PMCID: PMC9046277 DOI: 10.1038/s41467-022-29805-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Accepted: 03/29/2022] [Indexed: 11/09/2022] Open
Abstract
Dicke superradiance is an example of emergence of macroscopic quantum coherence via correlated dissipation. Starting from an initially incoherent state, a collection of excited atoms synchronizes as they decay, generating a macroscopic dipole moment and emitting a short and intense pulse of light. While well understood in cavities, superradiance remains an open problem in extended systems due to the exponential growth of complexity with atom number. Here we show that Dicke superradiance is a universal phenomenon in ordered arrays. We present a theoretical framework – which circumvents the exponential complexity of the problem – that allows us to predict the critical distance beyond which Dicke superradiance disappears. This critical distance is highly dependent on the dimensionality and atom number. Our predictions can be tested in state of the art experiments with arrays of neutral atoms, molecules, and solid-state emitters and pave the way towards understanding the role of many-body decay in quantum simulation, metrology, and lasing. Dicke superradiance is an important collective quantum phenomenon, but its analysis is hindered by the exponential growth of the state space with atom number. Here, the authors develop a theoretical framework that overcomes this, and predict a critical distance below which superradiant decay can be observed in large ordered arrays.
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Affiliation(s)
- Stuart J Masson
- Department of Physics, Columbia University, New York, NY, 10027, United States.
| | - Ana Asenjo-Garcia
- Department of Physics, Columbia University, New York, NY, 10027, United States.
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4
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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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5
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Glicenstein A, Ferioli G, Browaeys A, Ferrier-Barbut I. From superradiance to subradiance: exploring the many-body Dicke ladder. OPTICS LETTERS 2022; 47:1541-1544. [PMID: 35290359 DOI: 10.1364/ol.451903] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
We report a time-resolved study of collective emission in dense ensembles of two-level atoms. We compare, on the same sample, the buildup of superradiance and subradiance from the ensemble when driven by a strong laser. This allows us to measure the dynamics of the population of superradiant and subradiant states as a function of time. In particular, we demonstrate the buildup in time of subradiant states through superradiant dynamics. This illustrates the dynamics of the many-body density matrix of superradiant ensembles of two-level atoms when departing from the ideal conditions of Dicke superradiance, in which symmetry forbids the population of subradiant states.
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6
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Bianchet LC, Alves N, Zarraoa L, Bruno N, Mitchell MW. Manipulating and measuring single atoms in the Maltese cross geometry. OPEN RESEARCH EUROPE 2022; 1:102. [PMID: 37645131 PMCID: PMC10446080 DOI: 10.12688/openreseurope.13972.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 02/11/2022] [Indexed: 08/31/2023]
Abstract
Background: Optical microtraps at the focus of high numerical aperture (high-NA) imaging systems enable efficient collection, trapping, detection and manipulation of individual neutral atoms for quantum technology and studies of optical physics associated with super- and sub-radiant states. The recently developed "Maltese cross" geometry (MCG) atom trap uses four in-vacuum lenses to achieve four-directional high-NA optical coupling to single trapped atoms and small atomic arrays. This article presents the first extensive characterisation of atomic behaviour in a MCG atom trap. Methods: We employ a MCG system optimised for high coupling efficiency and characterise the resulting properties of the trap and trapped atoms. Using current best practices, we measure occupancy, loading rate, lifetime, temperature, fluorescence anti-bunching and trap frequencies. We also use the four-directional access to implement a new method to map the spatial distribution of collection efficiency from high-NA optics: we use the two on-trap-axis lenses to produce a 1D optical lattice, the sites of which are stochastically filled and emptied by the trap loading process. The two off-trap-axis lenses are used for imaging and single-mode collection. Correlations of single-mode and imaging fluorescence signals are then used to map the single-mode collection efficiency. Results: We observe trap characteristics comparable to what has been reported for single-atom traps with one- or two-lens optical systems. The collection efficiency distribution in the axial and transverse directions is directly observed to be in agreement with expected collection efficiency distribution from Gaussian beam optics. Conclusions: The multi-directional high-NA access provided by the Maltese cross geometry enables complex manipulations and measurements not possible in geometries with fewer directions of access, and can be achieved while preserving other trap characteristics such as lifetime, temperature, and trap size.
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Affiliation(s)
- Lorena C. Bianchet
- ICFO - Institut de Ciències Fotòniques, The Barcelona Institute of Science and Technology, Castelldefels, Barcelona, 08860, Spain
| | - Natalia Alves
- ICFO - Institut de Ciències Fotòniques, The Barcelona Institute of Science and Technology, Castelldefels, Barcelona, 08860, Spain
| | - Laura Zarraoa
- ICFO - Institut de Ciències Fotòniques, The Barcelona Institute of Science and Technology, Castelldefels, Barcelona, 08860, Spain
| | - Natalia Bruno
- Istituto Nazionale di Ottica (CNR-INO), Largo Enrico Fermi 6, Florence, 50125, Italy
- European Laboratory for Non-linear Spectroscopy (LENS), Via nello Carrara 1, 50019 Sesto Fiorentino, Florence, Italy
| | - Morgan W. Mitchell
- ICFO - Institut de Ciències Fotòniques, The Barcelona Institute of Science and Technology, Castelldefels, Barcelona, 08860, Spain
- ICREA - Institució Catalana de Recerca i Estudis Avançats, Barcelona, 08010, Spain
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7
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Ferioli G, Glicenstein A, Robicheaux F, Sutherland RT, Browaeys A, Ferrier-Barbut I. Laser-Driven Superradiant Ensembles of Two-Level Atoms near Dicke Regime. PHYSICAL REVIEW LETTERS 2021; 127:243602. [PMID: 34951804 DOI: 10.1103/physrevlett.127.243602] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Accepted: 11/03/2021] [Indexed: 06/14/2023]
Abstract
We report the experimental observation of a superradiant emission emanating from an elongated dense ensemble of laser cooled two-level atoms, with a radial extent smaller than the transition wavelength. In the presence of a strong driving laser, we observe that the system is superradiant along its symmmetry axis. This occurs even though the driving laser is orthogonal to the superradiance direction. This superradiance modifies the spontaneous emission, and, resultantly, the Rabi oscillations. We also investigate Dicke superradiance in the emission of an almost fully inverted system as a function of the atom number. The experimental results are in qualitative agreement with ab-initio, beyond-mean-field calculations.
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Affiliation(s)
- G Ferioli
- Université Paris-Saclay, Institut d'Optique Graduate School, CNRS, Laboratoire Charles Fabry, 91127, Palaiseau, France
| | - A Glicenstein
- Université Paris-Saclay, Institut d'Optique Graduate School, CNRS, Laboratoire Charles Fabry, 91127, Palaiseau, France
| | - F Robicheaux
- Department of Physics and Astronomy, Purdue University, West Lafayette, Indiana 47907, USA
- Purdue Quantum Science and Engineering Institute, Purdue University, West Lafayette, Indiana 47907, USA
| | - R T Sutherland
- Department of Electrical and Computer Engineering, Department of Physics and Astronomy, University of Texas at San Antonio, San Antonio, Texas 78249, USA
| | - A Browaeys
- Université Paris-Saclay, Institut d'Optique Graduate School, CNRS, Laboratoire Charles Fabry, 91127, Palaiseau, France
| | - I Ferrier-Barbut
- Université Paris-Saclay, Institut d'Optique Graduate School, CNRS, Laboratoire Charles Fabry, 91127, Palaiseau, France
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8
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Yoo SM. Optical cooperative effects of multiemitters in a one-dimensional (1D) dense array. OPTICS EXPRESS 2021; 29:35314-35326. [PMID: 34808968 DOI: 10.1364/oe.440558] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Accepted: 09/30/2021] [Indexed: 06/13/2023]
Abstract
We theoretically explore cooperative effects of equally spaced multiemitters in a 1D dense array driven by a low-intensity probe field propagating through a 1D waveguide by modeling the emitters as point-like coupled electric dipoles. We calculate the collective optical spectra of a number of 1D emitter arrays with any radiation-retention coefficient η using both exact classical-electrodynamics and mean-field-theory formalisms. We illustrate cooperative effects of lossless 1D emitter arrays with η = 1 at the emitter spacings, which are displayed by steep edges accompanied by a deep minimum and Fano resonances in the plots of transmissivities as a function of the detuning of the incident light from the emitter resonance. Numerical simulation of the full width of such optical bandgaps reveals that cooperativity between emitters is greater in a small array of size N ≤ 8 than in a larger one of size N > 8. For a lossy 1D emitter array in which the radiation retention coefficient is equal to or less than 0.1 the transmissivity obtained by exact-electrodynamics scheme exhibits no bandgap structures, being in good agreement with the mean-field-theory result. We propose that a 1D multiemitter array may work as a nanoscale filter blocking transmission of light with a frequency in the range of optical bandgaps.
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9
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Iversen OA, Pohl T. Strongly Correlated States of Light and Repulsive Photons in Chiral Chains of Three-Level Quantum Emitters. PHYSICAL REVIEW LETTERS 2021; 126:083605. [PMID: 33709742 DOI: 10.1103/physrevlett.126.083605] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Accepted: 01/06/2021] [Indexed: 06/12/2023]
Abstract
We study the correlated transport of photons through a chain of three-level emitters that are coupled chirally to a photonic mode of a waveguide. It is found that this system can transfer a weak classical input into a strongly correlated state of light in a unitary manner. Our analysis reveals two-photon scattering eigenstates, that are akin to Fano resonances or shape resonances in particle collisions and facilitate the emergence of antibunched light with long-range correlations upon crossing a critical length of the chain. By operating close to conditions of electromagnetically induced transparency of the three-level medium, a high degree of antibunching and photon transmission can be maintained in the presence of moderate losses. These features suggest a promising mechanism for single-photon generation and may open the door to exploring correlated quantum many-body states of light with repulsively interacting photons.
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Affiliation(s)
- Ole A Iversen
- Center for Complex Quantum Systems, Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK-8000 Aarhus C, Denmark
| | - Thomas Pohl
- Center for Complex Quantum Systems, Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK-8000 Aarhus C, Denmark
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10
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Masson SJ, Ferrier-Barbut I, Orozco LA, Browaeys A, Asenjo-Garcia A. Many-Body Signatures of Collective Decay in Atomic Chains. PHYSICAL REVIEW LETTERS 2020; 125:263601. [PMID: 33449783 DOI: 10.1103/physrevlett.125.263601] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Accepted: 11/16/2020] [Indexed: 06/12/2023]
Abstract
Fully inverted atoms placed at exactly the same location synchronize as they deexcite, and light is emitted in a burst (known as "Dicke's superradiance"). We investigate the role of finite interatomic separation on correlated decay in mesoscopic chains and provide an understanding in terms of collective jump operators. We show that the superradiant burst survives at small distances, despite Hamiltonian dipole-dipole interactions. However, for larger separations, competition between different jump operators leads to dephasing, suppressing superradiance. Collective effects are still significant for arrays with lattice constants of the order of a wavelength, and lead to a photon emission rate that decays nonexponentially in time. We calculate the two-photon correlation function and demonstrate that emission is correlated and directional, as well as sensitive to small changes in the interatomic distance. These features can be measured in current experimental setups, and are robust to realistic imperfections.
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Affiliation(s)
- Stuart J Masson
- Department of Physics, Columbia University, New York, New York 10027, USA
| | - Igor Ferrier-Barbut
- Université Paris-Saclay, Institut d'Optique Graduate School, CNRS, Laboratoire Charles Fabry, 91127 Paris, France
| | - Luis A Orozco
- Joint Quantum Institute, Department of Physics and NIST, University of Maryland, College Park, Maryland 20742, USA
| | - Antoine Browaeys
- Université Paris-Saclay, Institut d'Optique Graduate School, CNRS, Laboratoire Charles Fabry, 91127 Paris, France
| | - Ana Asenjo-Garcia
- Department of Physics, Columbia University, New York, New York 10027, USA
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11
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Williamson LA, Borgh MO, Ruostekoski J. Superatom Picture of Collective Nonclassical Light Emission and Dipole Blockade in Atom Arrays. PHYSICAL REVIEW LETTERS 2020; 125:073602. [PMID: 32857544 DOI: 10.1103/physrevlett.125.073602] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Accepted: 07/10/2020] [Indexed: 06/11/2023]
Abstract
We show that two-time, second-order correlations of scattered photons from planar arrays and chains of atoms display nonclassical features that can be described by a superatom picture of the canonical single-atom g_{2}(τ) resonance fluorescence result. For the superatom, the single-atom linewidth is replaced by the linewidth of the underlying collective low light-intensity eigenmode. Strong light-induced dipole-dipole interactions lead to a correlated response, suppressed joint photon detection events, and dipole blockade that inhibits multiple excitations of the collective atomic state. For targeted subradiant modes, the nonclassical nature of emitted light can be dramatically enhanced even compared with that of a single atom.
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Affiliation(s)
- L A Williamson
- Department of Physics, Lancaster University, Lancaster LA1 4YB, United Kingdom
| | - M O Borgh
- Faculty of Science, University of East Anglia, Norwich NR4 7TJ, United Kingdom
| | - J Ruostekoski
- Department of Physics, Lancaster University, Lancaster LA1 4YB, United Kingdom
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12
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Ballantine KE, Ruostekoski J. Radiative Toroidal Dipole and Anapole Excitations in Collectively Responding Arrays of Atoms. PHYSICAL REVIEW LETTERS 2020; 125:063201. [PMID: 32845681 DOI: 10.1103/physrevlett.125.063201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Accepted: 07/17/2020] [Indexed: 06/11/2023]
Abstract
A toroidal dipole represents an often overlooked electromagnetic excitation distinct from the standard electric and magnetic multipole expansion. We show how a simple arrangement of strongly radiatively coupled atoms can be used to synthesize a toroidal dipole where the toroidal topology is generated by radiative transitions forming an effective poloidal electric current wound around a torus. We extend the protocol for methods to prepare a delocalized collective excitation mode consisting of a synthetic lattice of such toroidal dipoles and a nonradiating, yet oscillating charge-current configuration, dynamic anapole, for which the far-field radiation of a toroidal dipole is identically canceled by an electric dipole.
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Affiliation(s)
- K E Ballantine
- Department of Physics, Lancaster University, Lancaster LA1 4YB, United Kingdom
| | - J Ruostekoski
- Department of Physics, Lancaster University, Lancaster LA1 4YB, United Kingdom
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