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Butera S, Carusotto I. Numerical Studies of Back Reaction Effects in an Analog Model of Cosmological Preheating. PHYSICAL REVIEW LETTERS 2023; 130:241501. [PMID: 37390448 DOI: 10.1103/physrevlett.130.241501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Revised: 01/25/2023] [Accepted: 05/15/2023] [Indexed: 07/02/2023]
Abstract
We theoretically propose an atomic Bose-Einstein condensate as an analog model of backreaction effects during the preheating stage of the early Universe. In particular, we address the out-of-equilibrium dynamics where the initially excited inflaton field decays by parametrically exciting the matter fields. We consider a two-dimensional, ring-shaped BEC under a tight transverse confinement whose transverse breathing mode and the Goldstone and dipole excitation branches simulate the inflaton and quantum matter fields, respectively. A strong excitation of the breathing mode leads to an exponentially growing emission of dipole and Goldstone excitations via parametric pair creation: Our numerical simulations of the BEC dynamics show how the associated backreaction effect results not only in an effective friction of the breathing mode, but also in a quick loss of longitudinal spatial coherence of the initially in-phase excitations. Implications of this result on the validity of the usual semiclassical description of backreaction are finally discussed.
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Affiliation(s)
- Salvatore Butera
- School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - Iacopo Carusotto
- Pitaevskii BEC Center, INO-CNR and Dipartimento di Fisica, Università di Trento, I-38123 Trento, Italy
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2
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Vettoliere A, Granata C. Highly Sensitive Tunable Magnetometer Based on Superconducting Quantum Interference Device. SENSORS (BASEL, SWITZERLAND) 2023; 23:s23073558. [PMID: 37050617 PMCID: PMC10098524 DOI: 10.3390/s23073558] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 03/20/2023] [Accepted: 03/27/2023] [Indexed: 06/12/2023]
Abstract
In the present article, experimental results regarding fully integrated superconducting quantum interference devices (SQUID), including a circuit to tune and optimize the main sensor device characteristics, are reported. We show the possibility of modifying the critical current of a SQUID magnetometer in liquid helium by means of a suitable heating circuit. This allows us to improve the characteristics of the SQUID sensor and in particular to optimize the voltage-magnetic flux characteristic and the relative transfer factor (responsivity) and consequently to also improve the flux and magnetic field noise. It is also possible to reset the SQUID sensor in case of entrapment of magnetic flux, avoiding taking it out of the helium bath. These results are very useful in view of most SQUID applications such as those requiring large multichannel systems in which it is desirable to optimize and eventually reset the magnetic sensors in a simple and effective way.
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Tian Z, Wu L, Zhang L, Jing J, Du J. Probing Lorentz-invariance-violation-induced nonthermal Unruh effect in quasi-two-dimensional dipolar condensates. Int J Clin Exp Med 2022. [DOI: 10.1103/physrevd.106.l061701] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Towards Quantum Simulation of Black Holes in a dc-SQUID Array. UNIVERSE 2021. [DOI: 10.3390/universe7120499] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
We propose quantum simulations of 1 + 1D radial sections of different black hole spacetimes (Schwarzschild, Reissner–Nordstrøm, Kerr and Kerr–Newman), by means of a dc-SQUID array embedded on an open transmission line. This was achieved by reproducing the spatiotemporal dependence of 1 + 1D sections of the spacetime metric with the propagation speed of the electromagnetic field in the simulator, which can be modulated by an external magnetic flux. We show that the generation of event horizons—and therefore Hawking radiation—in the simulator could be achieved for non-rotating black holes, although we discuss limitations related to fluctuations of the quantum phase. In the case of rotating black holes, it seems that the simulation of ergospheres is beyond reach.
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Abstract
We show under what conditions an accelerated detector (e.g., an atom/ion/molecule) thermalizes while interacting with the vacuum state of a quantum field in a setup where the detector’s acceleration alternates sign across multiple optical cavities. We show (non-perturbatively) in what regimes the probe ‘forgets’ that it is traversing cavities and thermalizes to a temperature proportional to its acceleration, the same as it would in free space. Then we analyze in detail how this thermalization relates to the renowned Unruh effect. Finally, we use these results to propose an experimental testbed for the direct detection of the Unruh effect at relatively low probe speeds and accelerations, potentially orders of magnitude below previous proposals.
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Quantum-circuit black hole lasers. Sci Rep 2021; 11:19137. [PMID: 34580347 PMCID: PMC8476520 DOI: 10.1038/s41598-021-98456-0] [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: 07/13/2021] [Accepted: 09/06/2021] [Indexed: 11/17/2022] Open
Abstract
A black hole laser in analogues of gravity amplifies Hawking radiation, which is unlikely to be measured in real black holes, and makes it observable. There have been proposals to realize such black hole lasers in various systems. However, no progress has been made in electric circuits for a long time, despite their many advantages such as high-precision electromagnetic wave detection. Here we propose a black hole laser in Josephson transmission lines incorporating metamaterial elements capable of producing Hawking-pair propagation modes and a Kerr nonlinearity due to the Josephson nonlinear inductance. A single dark soliton obeying the nonlinear Schrödinger equation produces a black hole-white hole horizon pair that acts as a laser cavity through a change in the refractive index due to the Kerr effect. We show that the resulting laser is a squeezed-state laser characterized by squeezing parameters. We also evaluate the degree of quantum correlation between Hawking and its partner radiations using entanglement entropy which does not require simultaneous measurements between them. As a result, the obtained entanglement entropy depending on the soliton velocity provides strong evidence that the resulting laser is derived from Hawking radiation with quantum correlation generated by pair production from the vacuum.
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Katayama H, Hatakenaka N, Fujii T. Analogue Hawking radiation from black hole solitons in quantum Josephson transmission lines. Int J Clin Exp Med 2020. [DOI: 10.1103/physrevd.102.086018] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Blencowe MP, Wang H. Analogue gravity on a superconducting chip. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2020; 378:20190224. [PMID: 32684136 PMCID: PMC7422880 DOI: 10.1098/rsta.2019.0224] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 05/06/2020] [Indexed: 06/11/2023]
Abstract
We describe how analogues of a Hawking evaporating black hole as well as the Unruh effect for an oscillatory, accelerating photodetector in vacuum may be realized using superconducting, microwave circuits that are fashioned out of Josephson tunnel junction and film bulk acoustic resonator elements. This article is part of a discussion meeting issue 'The next generation of analogue gravity experiments'.
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Affiliation(s)
- Miles P. Blencowe
- Department of Physics and Astronomy, Dartmouth College, Hanover, NH 03755, USA
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Schmit RP, Taketani BG, Wilhelm FK. Quantum simulation of particle creation in curved space-time. PLoS One 2020; 15:e0229382. [PMID: 32142551 PMCID: PMC7059940 DOI: 10.1371/journal.pone.0229382] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Accepted: 01/09/2020] [Indexed: 11/18/2022] Open
Abstract
Conversion of vacuum fluctuations into real particles was first predicted by L. Parker considering an expanding universe, followed in S. Hawking's work on black hole radiation. Since their experimental observation is challenging, analogue systems have gained attention in the verification of this concept. Here we propose an experimental set-up consisting of two adjacent piezoelectric semiconducting layers, one of them carrying dynamic quantum dots (DQDs), and the other being p-doped with an attached gate on top, which introduces a space-dependent layer conductivity. The propagation of surface acoustic waves (SAWs) on the latter layer is governed by a wave equation with an effective metric. In the frame of the DQDs, this space- and time-dependent metric possesses a sonic horizon for SAWs and resembles that of a two dimensional non-rotating and uncharged black hole to some extent. The non-thermal steady state of the DQD spin indicates particle creation in form of piezophonons.
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Affiliation(s)
- Raphael P. Schmit
- Theoretical Physics, Saarland University, Saarbrücken, Germany
- * E-mail:
| | - Bruno G. Taketani
- Theoretical Physics, Saarland University, Saarbrücken, Germany
- Departamento de Física, Universidade Federal de Santa Catarina, Florianópolis, SC, Brazil
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11
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Martín-Martínez E. Causality issues of particle detector models in QFT and quantum optics. Int J Clin Exp Med 2015. [DOI: 10.1103/physrevd.92.104019] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Martín-Martínez E, Aasen D, Kempf A. Processing quantum information with relativistic motion of atoms. PHYSICAL REVIEW LETTERS 2013; 110:160501. [PMID: 23679587 DOI: 10.1103/physrevlett.110.160501] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2012] [Indexed: 06/02/2023]
Abstract
We show that particle detectors, such as two-level atoms, in noninertial motion (or in gravitational fields) could be used to build quantum gates for the processing of quantum information. Concretely, we show that through suitably chosen noninertial trajectories of the detectors the interaction Hamiltonian's time dependence can be modulated to yield arbitrary rotations in the Bloch sphere due to relativistic quantum effects.
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Affiliation(s)
- Eduardo Martín-Martínez
- Institute for Quantum Computing, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L 3G1, Canada
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Chen YF, Hover D, Sendelbach S, Maurer L, Merkel ST, Pritchett EJ, Wilhelm FK, McDermott R. Microwave photon counter based on Josephson junctions. PHYSICAL REVIEW LETTERS 2011; 107:217401. [PMID: 22181922 DOI: 10.1103/physrevlett.107.217401] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2011] [Revised: 07/12/2011] [Indexed: 05/27/2023]
Abstract
We describe a microwave photon counter based on the current-biased Josephson junction. The junction is tuned to absorb single microwave photons from the incident field, after which it tunnels into a classically observable voltage state. Using two such detectors, we have performed a microwave version of the Hanbury Brown-Twiss experiment at 4 GHz and demonstrated a clear signature of photon bunching for a thermal source. The design is readily scalable to tens of parallelized junctions, a configuration that would allow number-resolved counting of microwave photons.
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Affiliation(s)
- Y-F Chen
- Department of Physics, University of Wisconsin, Madison, 53706, USA
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Martín-Martínez E, Fuentes I, Mann RB. Using Berry's phase to detect the Unruh effect at lower accelerations. PHYSICAL REVIEW LETTERS 2011; 107:131301. [PMID: 22026837 DOI: 10.1103/physrevlett.107.131301] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2010] [Indexed: 05/31/2023]
Abstract
We show that a detector acquires a Berry phase due to its motion in spacetime. The phase is different in the inertial and accelerated case as a direct consequence of the Unruh effect. We exploit this fact to design a novel method to measure the Unruh effect. Surprisingly, the effect is detectable for accelerations 10(9) times smaller than previous proposals sustained only for times of nanoseconds.
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Tian L. Circuit QED and sudden phase switching in a superconducting qubit array. PHYSICAL REVIEW LETTERS 2010; 105:167001. [PMID: 21230996 DOI: 10.1103/physrevlett.105.167001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2010] [Indexed: 05/30/2023]
Abstract
Superconducting qubits connected in an array can form quantum many-body systems such as the quantum Ising model. By coupling the qubits to a superconducting resonator, the combined system forms a circuit QED system. Here, we study the nonlinear behavior in the many-body state of the qubit array using a semiclassical approach. We show that sudden switchings as well as a bistable regime between the ferromagnetic phase and the paramagnetic phase can be observed in the qubit array. A superconducting circuit to implement this system is presented with realistic parameters.
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Affiliation(s)
- L Tian
- University of California, Merced, 5200 North Lake Road, Merced, California 95343, USA.
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Aspachs M, Adesso G, Fuentes I. Optimal quantum estimation of the Unruh-Hawking effect. PHYSICAL REVIEW LETTERS 2010; 105:151301. [PMID: 21230889 DOI: 10.1103/physrevlett.105.151301] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2010] [Indexed: 05/30/2023]
Abstract
We address on general quantum-statistical grounds the problem of optimal detection of the Unruh-Hawking effect. We show that the effect signatures are magnified up to potentially observable levels if the scalar field to be probed has high mean energy from an inertial perspective: The Unruh-Hawking effect acts like an amplification channel. We prove that a field in a Fock inertial state, probed via photon counting by a noninertial detector, realizes the optimal strategy attaining the ultimate sensitivity allowed by quantum mechanics for the observation of the effect. We define the parameter regime in which the effect can be reliably revealed in laboratory experiments, regardless of the specific implementation.
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Affiliation(s)
- Mariona Aspachs
- Grup de Física Teòrica, Universitat Autònoma de Barcelona, 08193 Bellaterra (Barcelona), Spain
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Johansson JR, Johansson G, Wilson CM, Nori F. Dynamical Casimir effect in a superconducting coplanar waveguide. PHYSICAL REVIEW LETTERS 2009; 103:147003. [PMID: 19905595 DOI: 10.1103/physrevlett.103.147003] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2009] [Indexed: 05/28/2023]
Abstract
We investigate the dynamical Casimir effect in a coplanar waveguide (CPW) terminated by a superconducting quantum interference device (SQUID). Changing the magnetic flux through the SQUID parametrically modulates the boundary condition of the CPW, and thereby, its effective length. Effective boundary velocities comparable to the speed of light in the CPW result in broadband photon generation which is identical to the one calculated in the dynamical Casimir effect for a single oscillating mirror. We estimate the power of the radiation for realistic parameters and show that it is experimentally feasible to directly detect this nonclassical broadband radiation.
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Affiliation(s)
- J R Johansson
- Advanced Science Institute, The Institute of Physical and Chemical Research (RIKEN), Wako-shi, Saitama 351-0198, Japan
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