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Baak JG, Fischer UR. Self-Consistent Many-Body Metrology. PHYSICAL REVIEW LETTERS 2024; 132:240803. [PMID: 38949355 DOI: 10.1103/physrevlett.132.240803] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2023] [Accepted: 04/29/2024] [Indexed: 07/02/2024]
Abstract
We investigate the classical and quantum metrology of performing parameter estimation with interacting trapped bosons, which we theoretically treat by a self-consistent many-body approach of the multiconfigurational Hartree type. Focusing on a tilted double-well geometry, we compare a self-consistently determined and monitored two-mode truncation, with dynamically changing orbitals, to the conventional two-mode approach of fixed orbitals, where only Fock space coefficients evolve in time. We demonstrate that, as a consequence, various metrological quantities associated to a concrete measurement such as the classical Fisher information and the maximum likelihood estimator are deeply affected by the orbitals' change during the quantum evolution. Self-consistency of the quantum many-body dynamics of interacting trapped ultracold gases thus fundamentally affects the attainable parameter estimation accuracy of a given metrological protocol.
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Affiliation(s)
- Jae-Gyun Baak
- Seoul National University, Department of Physics and Astronomy, Center for Theoretical Physics, Seoul 08826, Korea
| | - Uwe R Fischer
- Seoul National University, Department of Physics and Astronomy, Center for Theoretical Physics, Seoul 08826, Korea
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2
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Grün DS, Ymai LH, Wittmann W K, Tonel AP, Foerster A, Links J. Integrable Atomtronic Interferometry. PHYSICAL REVIEW LETTERS 2022; 129:020401. [PMID: 35867439 DOI: 10.1103/physrevlett.129.020401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Accepted: 05/23/2022] [Indexed: 06/15/2023]
Abstract
High sensitivity quantum interferometry requires more than just access to entangled states. It is achieved through the deep understanding of quantum correlations in a system. Integrable models offer the framework to develop this understanding. We communicate the design of interferometric protocols for an integrable model that describes the interaction of bosons in a four-site configuration. Analytic formulas for the quantum dynamics of certain observables are computed. These expose the system's functionality as both an interferometric identifier, and producer, of NOON states. Being equivalent to a controlled-phase gate acting on 2 hybrid qudits, this system also highlights an equivalence between Heisenberg-limited interferometry and quantum information. These results are expected to open new avenues for integrability-enhanced atomtronic technologies.
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Affiliation(s)
- D S Grün
- Instituto de Física da UFRGS, Avenida Bento Gonçalves, 9500 Porto Alegre, Rio Grande do Sul, Brazil
| | - L H Ymai
- Universidade Federal do Pampa, Avenida Maria Anunciação Gomes de Godoy, 1650 Bagé, Rio Grande do Sul, Brazil
| | - K Wittmann W
- Instituto de Física da UFRGS, Avenida Bento Gonçalves, 9500 Porto Alegre, Rio Grande do Sul, Brazil
| | - A P Tonel
- Universidade Federal do Pampa, Avenida Maria Anunciação Gomes de Godoy, 1650 Bagé, Rio Grande do Sul, Brazil
| | - A Foerster
- Instituto de Física da UFRGS, Avenida Bento Gonçalves, 9500 Porto Alegre, Rio Grande do Sul, Brazil
| | - J Links
- School of Mathematics and Physics, The University of Queensland, Brisbane 4072, Queensland, Australia
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Cai Y, Allman DG, Sabharwal P, Wright KC. Persistent Currents in Rings of Ultracold Fermionic Atoms. PHYSICAL REVIEW LETTERS 2022; 128:150401. [PMID: 35499879 DOI: 10.1103/physrevlett.128.150401] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Revised: 12/31/2021] [Accepted: 03/01/2022] [Indexed: 06/14/2023]
Abstract
We have produced persistent currents of ultracold fermionic atoms trapped in a ring, with lifetimes greater than 10 sec in the strongly interacting regime. These currents remain stable well into the BCS regime at sufficiently low temperature. We drive a circulating BCS superfluid into the normal phase and back by changing the interaction strength and find that the probability for quantized superflow to reappear is remarkably insensitive to the time spent in the normal phase and the minimum interaction strength. After ruling out spontaneous current formation for our experimental conditions, we argue that the reappearance of superflow is due to weak damping of normal currents in this limit. These results establish that ultracold fermionic atoms with tunable interactions can be used to create matter-wave circuits similar to those previously created with weakly interacting bosonic atoms.
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Affiliation(s)
- Yanping Cai
- Department of Physics and Astronomy, Dartmouth College, 6127 Wilder Laboratory, Hanover, New Hampshire 03755, USA
| | - Daniel G Allman
- Department of Physics and Astronomy, Dartmouth College, 6127 Wilder Laboratory, Hanover, New Hampshire 03755, USA
| | - Parth Sabharwal
- Department of Physics and Astronomy, Dartmouth College, 6127 Wilder Laboratory, Hanover, New Hampshire 03755, USA
| | - Kevin C Wright
- Department of Physics and Astronomy, Dartmouth College, 6127 Wilder Laboratory, Hanover, New Hampshire 03755, USA
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Kumar P, Biswas T, Feliz K, Kanamoto R, Chang MS, Jha AK, Bhattacharya M. Cavity Optomechanical Sensing and Manipulation of an Atomic Persistent Current. PHYSICAL REVIEW LETTERS 2021; 127:113601. [PMID: 34558916 DOI: 10.1103/physrevlett.127.113601] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Accepted: 07/28/2021] [Indexed: 06/13/2023]
Abstract
This theoretical work initiates contact between two frontier disciplines of physics, namely, atomic superfluid rotation and cavity optomechanics. It considers an annular Bose-Einstein condensate, which exhibits dissipationless flow and is a paradigm of rotational quantum physics, inside a cavity excited by optical fields carrying orbital angular momentum. It provides the first platform that can sense ring Bose-Einstein condensate rotation with minimal destruction, in situ and in real time, unlike demonstrated techniques, all of which involve fully destructive measurement. It also shows how light can actively manipulate rotating matter waves by optomechanically entangling persistent currents. Our work opens up a novel and useful direction in the sensing and manipulation of atomic superflow.
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Affiliation(s)
- Pardeep Kumar
- School of Physics and Astronomy, Rochester Institute of Technology, 84 Lomb Memorial Drive, Rochester, New York 14623, USA
| | - Tushar Biswas
- School of Physics and Astronomy, Rochester Institute of Technology, 84 Lomb Memorial Drive, Rochester, New York 14623, USA
| | - Kristian Feliz
- School of Physics and Astronomy, Rochester Institute of Technology, 84 Lomb Memorial Drive, Rochester, New York 14623, USA
| | - Rina Kanamoto
- Department of Physics, Meiji University, Kawasaki, Kanagawa 214-8571, Japan
| | - M-S Chang
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan
- Department of Physics and Center for Quantum Technology, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Anand K Jha
- Department of Physics, Indian Institute of Technology, Kanpur, Uttar Pradesh 208016, India
| | - M Bhattacharya
- School of Physics and Astronomy, Rochester Institute of Technology, 84 Lomb Memorial Drive, Rochester, New York 14623, USA
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Ryu C, Samson EC, Boshier MG. Quantum interference of currents in an atomtronic SQUID. Nat Commun 2020; 11:3338. [PMID: 32620901 PMCID: PMC7335076 DOI: 10.1038/s41467-020-17185-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Accepted: 06/15/2020] [Indexed: 11/18/2022] Open
Abstract
Quantum interference of currents is the most important and well known quantum phenomenon in a conventional superconducting quantum interference device (SQUID). Here, we report the observation of quantum interference of currents in an atomtronic SQUID. Analogous to a conventional SQUID, currents flowing through two junctions in an atomtronic SQUID interfere due to the phase difference from rotation. This interference results in modulation of critical currents. This modulation was observed for three different radii with clear modulation periods which were measured to be consistent with fundamental rotation rates. This observation shows the possibility of studying various interesting SQUID physics with an atomtronic SQUID and especially, macroscopic quantum phenomena with currents may be realized with an atomtronic SQUID toward the goal of quantum metrology of rotation sensing. Quantum interference of currents was first observed in a superconducting quantum interference device (SQUID). Here, the authors demonstrate quantum interference of currents in the atomtronic analog of a SQUID using Bose-Einstein condensates of 87Rb atoms.
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Affiliation(s)
- C Ryu
- Physics Division, Los Alamos National Laboratory, Los Alamos, NM, USA.
| | - E C Samson
- Physics Division, Los Alamos National Laboratory, Los Alamos, NM, USA.,Department of Physics, Miami University, Oxford, OH, USA
| | - M G Boshier
- Physics Division, Los Alamos National Laboratory, Los Alamos, NM, USA
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Helm JL, Billam TP, Rakonjac A, Cornish SL, Gardiner SA. Spin-Orbit-Coupled Interferometry with Ring-Trapped Bose-Einstein Condensates. PHYSICAL REVIEW LETTERS 2018; 120:063201. [PMID: 29481231 DOI: 10.1103/physrevlett.120.063201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Indexed: 06/08/2023]
Abstract
We propose a method of atom interferometry using a spinor Bose-Einstein condensate with a time-varying magnetic field acting as a coherent beam splitter. Our protocol creates long-lived superpositional counterflow states, which are of fundamental interest and can be made sensitive to both the Sagnac effect and magnetic fields on the sub-μG scale. We split a ring-trapped condensate, initially in the m_{f}=0 hyperfine state, into superpositions of internal m_{f}=±1 states and condensate superflow, which are spin-orbit coupled. After interrogation, the relative phase accumulation can be inferred from a population transfer to the m_{f}=±1 states. The counterflow generation protocol is adiabatically deterministic and does not rely on coupling to additional optical fields or mechanical stirring techniques. Our protocol can maximize the classical Fisher information for any rotation, magnetic field, or interrogation time and so has the maximum sensitivity available to uncorrelated particles. Precision can increase with the interrogation time and so is limited only by the lifetime of the condensate.
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Affiliation(s)
- J L Helm
- The Dodd-Walls Centre for Photonic and Quantum Technologies, Department of Physics, University of Otago, Dunedin 9016, New Zealand
| | - T P Billam
- Joint Quantum Center (JQC) Durham-Newcastle, School of Mathematics, Statistics and Physics, Newcastle University, Newcastle upon Tyne NE1 7RU, United Kingdom
| | - A Rakonjac
- Joint Quantum Center (JQC) Durham-Newcastle, Department of Physics, Durham University, Durham DH1 3LE, United Kingdom
| | - S L Cornish
- Joint Quantum Center (JQC) Durham-Newcastle, Department of Physics, Durham University, Durham DH1 3LE, United Kingdom
| | - S A Gardiner
- Joint Quantum Center (JQC) Durham-Newcastle, Department of Physics, Durham University, Durham DH1 3LE, United Kingdom
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Eldredge Z, Foss-Feig M, Gross JA, Rolston SL, Gorshkov AV. Optimal and secure measurement protocols for quantum sensor networks. PHYSICAL REVIEW. A 2018; 97:10.1103/PhysRevA.97.042337. [PMID: 31093589 PMCID: PMC6513338 DOI: 10.1103/physreva.97.042337] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Studies of quantum metrology have shown that the use of many-body entangled states can lead to an enhancement in sensitivity when compared with unentangled states. In this paper, we quantify the metrological advantage of entanglement in a setting where the measured quantity is a linear function of parameters individually coupled to each qubit. We first generalize the Heisenberg limit to the measurement of nonlocal observables in a quantum network, deriving a bound based on the multiparameter quantum Fisher information. We then propose measurement protocols that can make use of Greenberger-Horne-Zeilinger (GHZ) states or spin-squeezed states and show that in the case of GHZ states the protocol is optimal, i.e., it saturates our bound. We also identify nanoscale magnetic resonance imaging as a promising setting for this technology.
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Affiliation(s)
- Zachary Eldredge
- Joint Quantum Institute, NIST/University of Maryland, College Park, Maryland 20742, USA
- Joint Center for Quantum Information and Computer Science, NIST/University of Maryland, College Park, Maryland 20742, USA
| | - Michael Foss-Feig
- Joint Quantum Institute, NIST/University of Maryland, College Park, Maryland 20742, USA
- Joint Center for Quantum Information and Computer Science, NIST/University of Maryland, College Park, Maryland 20742, USA
- United States Army Research Laboratory, Adelphi, Maryland 20783, USA
| | - Jonathan A Gross
- Center for Quantum Information and Control, University of New Mexico, Albuquerque, New Mexico 87131, USA
| | - S L Rolston
- Joint Quantum Institute, NIST/University of Maryland, College Park, Maryland 20742, USA
| | - Alexey V Gorshkov
- Joint Quantum Institute, NIST/University of Maryland, College Park, Maryland 20742, USA
- Joint Center for Quantum Information and Computer Science, NIST/University of Maryland, College Park, Maryland 20742, USA
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