Observation of Dynamical Quantum Phase Transitions with Correspondence in an Excited State Phase Diagram

Tian, Tonghua; Yang, Huizhu; Qiu, Liyuan; Liang, Hongyu; Yang, Yan-Bin; Xu, Yong; Duan, L.-M.

doi:10.1103/physrevlett.124.043001

Cited by 111 publications

(82 citation statements)

References 57 publications

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“…They can be identified by their consequences in the classical [25] and semiclassical [26,27] phase-space dynamics [28,29], as in the singularities of the density of states [30]. Its signatures have been theoretically and experimentally observed in several physical systems [31][32][33][34][35][36], and its connections with quantum Lyapunov exponents have been explored [37][38][39]. However, no physical features of standard phase transitions have been identified yet.…”

mentioning

confidence: 99%

Constant of Motion Identifying Excited-State Quantum Phases

Corps

Relaño

2021

Phys. Rev. Lett.

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We propose that a broad class of excited-state quantum phase transitions (ESQPTs) gives rise to two different excited-state quantum phases. These phases are identified by means of an operator Ĉ, which is a constant of motion in only one of them. Hence, the ESQPT critical energy splits the spectrum into one phase where the equilibrium expectation values of physical observables crucially depend on this constant of motion and another phase where the energy is the only relevant thermodynamic magnitude. The trademark feature of this operator is that it has two different eigenvalues AE1, and, therefore, it acts as a discrete symmetry in the first of these two phases. This scenario is observed in systems with and without an additional discrete symmetry; in the first case, Ĉ explains the change from degenerate doublets to nondegenerate eigenlevels upon crossing the critical line. We present stringent numerical evidence in the Rabi and Dicke models, suggesting that this result is exact in the thermodynamic limit, with finite-size corrections that decrease as a power law.

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mentioning

confidence: 99%

Constant of Motion Identifying Excited-State Quantum Phases

Corps

Relaño

2021

Phys. Rev. Lett.

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“…Another appealing extension of the present work would be to explore the phase space signatures of ESQPTs associated with a first-order ground-state QPT [43]. Finally, given that the Husimi function has been measured in several experiments [116][117][118][119], and that it is possible to obtain realizations of the two models studied in this work in quantum simulators [52,100,109,120], we expect that the present results can be experimentally tested. equations of motions (EOMs) are obtained from the semiclassical approach.…”

Section: Discussionmentioning

confidence: 86%

“…ESQPTs have been identified in different quantum systems [40][41][42][43][44][45][46][47][48]. Moreover, ESQPT's experimental signatures have also been found in various many-body systems [49][50][51][52][53]. Many of these works pay heed to ESQPT effects over nonequilibrium properties of quantum many-body systems [54][55][56][57][58][59][60][61][62][63][64].…”

Section: Introductionmentioning

confidence: 99%

Signatures of excited-state quantum phase transitions in quantum many-body systems: Phase space analysis

Wang

Pérez‐Bernal

2021

Phys. Rev. E

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Using the Husimi quasiprobability distribution, we investigate the phase space signatures of excited-state quantum phase transitions (ESQPTs) in the Lipkin-Meshkov-Glick and coupled top models. We show that the ESQPT is evinced by the dynamics of the Husimi function, that exhibits a distinct time dependence in the different ESQPT phases. We also discuss how to identify the ESQPT signatures from the long-time averaged Husimi function and its associated marginal distributions. Moreover, from the calculated second moment and Wherl entropy of the long-time averaged Husimi function, we estimate the critical points of the ESQPT in both models, obtaining a good agreement with analytical (mean field) results. We provide a firm evidence that phase space methods are both a new probe for the detection and a valuable tool for the study of ESQPTs.

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“…A spinor BEC provides a versatile platform to study the nonequilibrium physics, such as spin domains (22)(23)(24)(25)(26), topological defects (27)(28)(29)(30), the KZM through the second-order phase transition (11), and dynamical quantum phase transitions (31,32). The condensate is described by a vector order parameter.…”

Section: Introductionmentioning

confidence: 99%

Observation of generalized Kibble-Zurek mechanism across a first-order quantum phase transition in a spinor condensate

et al. 2020

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The Kibble-Zurek mechanism provides a unified theory to describe the universal scaling laws in the dynamics when a system is driven through a second-order quantum phase transition. However, for first-order quantum phase transitions, the Kibble-Zurek mechanism is usually not applicable. Here, we experimentally demonstrate and theoretically analyze a power-law scaling in the dynamics of a spin-1 condensate across a first-order quantum phase transition when a system is slowly driven from a polar phase to an antiferromagnetic phase. We show that this power-law scaling can be described by a generalized Kibble-Zurek mechanism. Furthermore, by experimentally measuring the spin population, we show the power-law scaling of the temporal onset of spin excitations with respect to the quench rate, which agrees well with our numerical simulation results. Our results open the door for further exploring the generalized Kibble-Zurek mechanism to understand the dynamics across first-order quantum phase transitions.

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Observation of Dynamical Quantum Phase Transitions with Correspondence in an Excited State Phase Diagram

Cited by 111 publications

References 57 publications

Constant of Motion Identifying Excited-State Quantum Phases

Constant of Motion Identifying Excited-State Quantum Phases

Signatures of excited-state quantum phase transitions in quantum many-body systems: Phase space analysis

Observation of generalized Kibble-Zurek mechanism across a first-order quantum phase transition in a spinor condensate

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