scholarly journals Probing dynamical phase transitions with a superconducting quantum simulator

2020 ◽  
Vol 6 (25) ◽  
pp. eaba4935
Author(s):  
Kai Xu ◽  
Zheng-Hang Sun ◽  
Wuxin Liu ◽  
Yu-Ran Zhang ◽  
Hekang Li ◽  
...  
Keyword(s):  
Phase Transitions ◽  
Quantum Limit ◽  
Single Shot ◽  
Many Body ◽  
Dynamical Phase Transition ◽  
Dynamical Phase ◽  
Dynamical Phase Transitions ◽  
Quantum Simulator ◽  
Many Body Systems ◽  
Loschmidt Echo

Nonequilibrium quantum many-body systems, which are difficult to study via classical computation, have attracted wide interest. Quantum simulation can provide insights into these problems. Here, using a programmable quantum simulator with 16 all-to-all connected superconducting qubits, we investigate the dynamical phase transition in the Lipkin-Meshkov-Glick model with a quenched transverse field. Clear signatures of dynamical phase transitions, merging different concepts of dynamical criticality, are observed by measuring the nonequilibrium order parameter, nonlocal correlations, and the Loschmidt echo. Moreover, near the dynamical critical point, we obtain a spin squeezing of −7.0 ± 0.8 dB, showing multipartite entanglement, useful for measurements with precision fivefold beyond the standard quantum limit. On the basis of the capability of entangling qubits simultaneously and the accurate single-shot readout of multiqubit states, this superconducting quantum simulator can be used to study other problems in nonequilibrium quantum many-body systems, such as thermalization, many-body localization, and emergent phenomena in periodically driven systems.

scholarly journals Dynamical Phase Transitions and Instabilities in Open Atomic Many-Body Systems

2010 ◽  
Vol 105 (1) ◽  
Author(s):  
Sebastian Diehl ◽  
Andrea Tomadin ◽  
Andrea Micheli ◽  
Rosario Fazio ◽  
Peter Zoller
Keyword(s):  
Phase Transitions ◽  
Many Body ◽  
Dynamical Phase ◽  
Dynamical Phase Transitions ◽  
Many Body Systems

scholarly journals Dynamical phase transitions at finite temperature from fidelity and interferometric Loschmidt echo induced metrics

2018 ◽  
Vol 97 (9) ◽  
Author(s):  
Bruno Mera ◽  
Chrysoula Vlachou ◽  
Nikola Paunković ◽  
Vítor R. Vieira ◽  
Oscar Viyuela
Keyword(s):  
Phase Transitions ◽  
Finite Temperature ◽  
Dynamical Phase ◽  
Dynamical Phase Transitions ◽  
Loschmidt Echo

scholarly journals Dynamical phase transitions and Loschmidt echo in the infinite-range XY model

2016 ◽  
Vol 374 (2069) ◽  
pp. 20150160 ◽  
Author(s):  
Bojan Žunkovič ◽  
Alessandro Silva ◽  
Michele Fabrizio
Keyword(s):  
Phase Transition ◽  
Phase Transitions ◽  
Order Parameter ◽  
Quantum Systems ◽  
Xy Model ◽  
Time Behaviour ◽  
Dynamical Phase ◽  
Dynamical Phase Transitions ◽  
Loschmidt Echo ◽  
Infinite Range

We compare two different notions of dynamical phase transitions in closed quantum systems. The first is identified through the time-averaged value of the equilibrium-order parameter, whereas the second corresponds to non-analyticities in the time behaviour of the Loschmidt echo. By exactly solving the dynamics of the infinite-range XY model, we show that in this model non-analyticities of the Loschmidt echo are not connected to standard dynamical phase transitions and are not robust against quantum fluctuations. Furthermore, we show that the existence of either of the two dynamical transitions is not necessarily connected to the equilibrium quantum phase transition.

DYNAMICAL PHASE TRANSITIONS ON COMB LATTICES

1992 ◽  
Vol 06 (29) ◽  
pp. 1887-1891
Author(s):  
D. CASSI ◽  
S. REGINA
Keyword(s):  
Phase Transition ◽  
Phase Transitions ◽  
Critical Point ◽  
Critical Exponents ◽  
Analytical Techniques ◽  
Spectral Dimension ◽  
Dynamical Phase Transition ◽  
Dynamical Phase ◽  
Dynamical Phase Transitions ◽  
Bethe Lattices

We study by analytical techniques the dynamical phase transition between recursive and transient regime induced on comb lattices by a topological bias. The critical exponents are expressed as functions of the intrinsic dimensions of these structures. In particular we show that, unlike what happens on Bethe lattices, it takes in general two different exponents to characterize the approach to the critical point from the recursive phase and from the transient one. These exponents depend respectively on the connectivity and on the spectral dimension.

scholarly journals Observation of a many-body dynamical phase transition with a 53-qubit quantum simulator

Nature ◽  
2017 ◽  
Vol 551 (7682) ◽  
pp. 601-604 ◽  
Author(s):  
J. Zhang ◽  
G. Pagano ◽  
P. W. Hess ◽  
A. Kyprianidis ◽  
P. Becker ◽  
...  
Keyword(s):  
Phase Transition ◽  
Many Body ◽  
Dynamical Phase Transition ◽  
Dynamical Phase ◽  
Quantum Simulator

scholarly journals Probing phase transitions of holographic entanglement entropy with fixed area states

2020 ◽  
Vol 2020 (12) ◽  
Author(s):  
Donald Marolf ◽  
Shannon Wang ◽  
Zhencheng Wang
Keyword(s):  
Phase Transitions ◽  
Entanglement Entropy ◽  
Many Body ◽  
Btz Black Hole ◽  
Holographic Entanglement Entropy ◽  
Volume Limit ◽  
Cutoff Dependence ◽  
Diagonal Approximation ◽  
Fixed Area ◽  
Many Body Systems

Abstract Recent results suggest that new corrections to holographic entanglement entropy should arise near phase transitions of the associated Ryu-Takayanagi (RT) surface. We study such corrections by decomposing the bulk state into fixed-area states and conjecturing that a certain ‘diagonal approximation’ will hold. In terms of the bulk Newton constant G, this yields a correction of order O(G−1/2) near such transitions, which is in particular larger than generic corrections from the entanglement of bulk quantum fields. However, the correction becomes exponentially suppressed away from the transition. The net effect is to make the entanglement a smooth function of all parameters, turning the RT ‘phase transition’ into a crossover already at this level of analysis.We illustrate this effect with explicit calculations (again assuming our diagonal approximation) for boundary regions given by a pair of disconnected intervals on the boundary of the AdS3 vacuum and for a single interval on the boundary of the BTZ black hole. In a natural large-volume limit where our diagonal approximation clearly holds, this second example verifies that our results agree with general predictions made by Murthy and Srednicki in the context of chaotic many-body systems. As a further check on our conjectured diagonal approximation, we show that it also reproduces the O(G−1/2) correction found Penington et al. for an analogous quantum RT transition. Our explicit computations also illustrate the cutoff-dependence of fluctuations in RT-areas.

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