Discrete time crystals in Bose-Einstein Condensates and symmetry-breaking edge in a simple two-mode theory

• URL: http://arxiv.org/abs/2106.02219v3
• Date: Tue, 30 Nov 2021 23:38:19 GMT
• Title: Discrete time crystals in Bose-Einstein Condensates and symmetry-breaking edge in a simple two-mode theory
• Authors: Jia Wang, Krzysztof Sacha, Peter Hannaford, Bryan J. Dalton
• Abstract summary: Discrete time crystals (DTCs) refer to a novel many-body steady state that spontaneously breaks the discrete time-translational symmetry in a periodically-driven quantum system. We study DTCs in a Bose-Einstein condensate (BEC) bouncing resonantly on an oscillating mirror, using a two-mode model derived from a standard quantum field theory. We find that according to this two-mode model, the discrete time crystal survives for times out to at least 250,000 driving periods.
• Score: 2.847745514392761
• License: http://creativecommons.org/licenses/by/4.0/
• Abstract: Discrete time crystals (DTCs) refer to a novel many-body steady state that spontaneously breaks the discrete time-translational symmetry in a periodically-driven quantum system. Here, we study DTCs in a Bose-Einstein condensate (BEC) bouncing resonantly on an oscillating mirror, using a two-mode model derived from a standard quantum field theory. We investigate the validity of this model and apply it to study the long-time behavior of our system. A wide variety of initial states based on two Wannier modes are considered. We find that in previous studies the investigated phenomena in the evolution time-window ($\lessapprox$2000 driving periods) are actually "short-time" transient behavior though DTC formation signaled by the sub-harmonic responses is still shown if the inter-boson interaction is strong enough. After a much longer (about 20 times) evolution time, initial states with no "long-range" correlations relax to a steady state, where time-symmetry breaking can be unambiguously defined. Quantum revivals also eventually occur. This long-time behavior can be understood via the many-body Floquet quasi-eigenenergy spectrum of the two-mode model. A symmetry-breaking edge for DTC formation appears in the spectrum for strong enough interaction, where all quasi-eigenstates below the edge are symmetry-breaking while those above the edge are symmetric. The late-time steady state's time-translational symmetry depends solely on whether the initial energy is above or below the symmetry-breaking edge. A phase diagram showing regions of symmetry-broken and symmetric phases for differing initial energies and interaction strengths is presented. We find that according to this two-mode model, the discrete time crystal survives for times out to at least 250,000 driving periods.

Related papers

• Spatial inversion symmetry breaking of vortex current in biased-ladder superfluid [5.128355665808276]
  We investigate the dynamics of interacting bosons on a two-leg ladder in presence of a uniform Abelian gauge field. The model hosts a variety of emergent quantum phases, and we focus on the superfluid biased-ladder phase breaking the $Z_2$ symmetry of two legs.
  arXiv  Detail & Related papers  (2023-07-29T05:20:59Z)
• A Solvable Model for Discrete Time Crystal Enforced by Nonsymmorphic Dynamical Symmetry [9.803965066368757]
  We propose a class of discrete time crystals enforced by nonsymmorphic dynamical symmetry. The exact solution of the time-dependent Schr"odinger equation shows that the system spontaneously exhibits a period extension. We show that the subharmonic response is stable even when many-body interactions are introduced, indicating a DTC phase in the thermodynamic limit.
  arXiv  Detail & Related papers  (2023-05-27T01:51:29Z)
• Quantum chaos and thermalization in the two-mode Dicke model [77.34726150561087]
  We discuss the onset of quantum chaos and thermalization in the two-mode Dicke model. The two-mode Dicke model exhibits normal to superradiant quantum phase transition. We show that the temporal fluctuations of the expectation value of the collective spin observable around its average are small and decrease with the effective system size.
  arXiv  Detail & Related papers  (2022-07-08T11:16:29Z)
• Clean two-dimensional Floquet time-crystal [68.8204255655161]
  We consider the two-dimensional quantum Ising model, in absence of disorder, subject to periodic imperfect global spin flips. We show by a combination of exact diagonalization and tensor-network methods that the system can sustain a spontaneously broken discrete time-translation symmetry. We observe a non-perturbative change in the decay rate of the order parameter, which is related to the long-lived stability of the magnetic domains in 2D.
  arXiv  Detail & Related papers  (2022-05-10T13:04:43Z)
• Tuning between continuous time crystals and many-body scars in long-range XYZ spin chains [0.13764085113103217]
  We investigate the possibility of a emphcontinuous time crystal (CTC) in undriven, energy-conserving systems exhibiting prethermalization. We map out the dynamical phase diagram using numerical simulations based on exact diagonalization and time-dependent variational principle in the thermodynamic limit. We identify a regime where QMBS and CTC order co-exist, and we discuss experimental protocols that reveal their similarities as well as key differences.
  arXiv  Detail & Related papers  (2022-05-04T18:00:03Z)
• The role of fluctuations in quantum and classical time crystals [58.720142291102135]
  We study the role of fluctuations on the stability of the system and find no distinction between quantum and classical DTCs. This allows us to probe the fluctuations in an experiment using two strongly coupled parametric resonators subject to classical noise.
  arXiv  Detail & Related papers  (2022-03-10T19:00:01Z)
• Genuine Multipartite Correlations in a Boundary Time Crystal [56.967919268256786]
  We study genuine multipartite correlations (GMC's) in a boundary time crystal (BTC) We analyze both (i) the structure (orders) of GMC's among the subsystems, as well as (ii) their build-up dynamics for an initially uncorrelated state.
  arXiv  Detail & Related papers  (2021-12-21T20:25:02Z)
• Observation of Time-Crystalline Eigenstate Order on a Quantum Processor [80.17270167652622]
  Quantum-body systems display rich phase structure in their low-temperature equilibrium states. We experimentally observe an eigenstate-ordered DTC on superconducting qubits. Results establish a scalable approach to study non-equilibrium phases of matter on current quantum processors.
  arXiv  Detail & Related papers  (2021-07-28T18:00:03Z)
• Breaking strong symmetries in dissipative quantum systems: Bosonic atoms coupled to a cavity [0.0]
  In dissipative quantum systems, strong symmetries can lead to the existence of conservation laws and multiple steady states. We show that for ideal bosons coupled to the cavity multiple steady states exist and in each symmetry sector a dissipative phase transition occurs at a different critical point. We point out the phenomenon of dissipative freezing, the breaking of the conservation law at the level of individual realizations in the presence of the strong symmetry.
  arXiv  Detail & Related papers  (2021-02-04T10:54:31Z)
• Collective spontaneous emission of two entangled atoms near an oscillating mirror [50.591267188664666]
  We consider the cooperative spontaneous emission of a system of two identical atoms, interacting with the electromagnetic field in the vacuum state. Using time-dependent theory, we investigate the spectrum of the radiation emitted by the two-atom system. We show that it is modulated in time, and that the presence of the oscillating mirror can enhance or inhibit the decay rate.
  arXiv  Detail & Related papers  (2020-10-07T06:48:20Z)
• Condensed Matter Physics in Time Crystals [0.0]
  Floquet time-translation symmetry is allowed to be spontaneously broken in periodically driven systems. This review aims to summarise the very preliminary results in this new research field with an analogous structure of condensed matter theory in solids. The whole theory is built on a hidden symmetry in time crystals, i.e., the phase space lattice symmetry.
  arXiv  Detail & Related papers  (2020-05-06T21:10:14Z)

This list is automatically generated from the titles and abstracts of the papers in this site.

This site does not guarantee the quality of this site (including all information) and is not responsible for any consequences.