Detecting Out-of-Time-Order Correlations via Quasiadiabatic Echoes as a Tool to Reveal Quantum Coherence in Equilibrium Quantum Phase Transitions

Lewis-Swan, Robert J.; Muleady, Sean R.; Rey, Ana María

doi:10.1103/physrevlett.125.240605

Cited by 26 publications

(19 citation statements)

References 71 publications

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“…Entanglement entropy and OTOC are two quantities that are of great interest in dynamical studies of quantum systems with the second one being easier to be implemented in experiments. Very recently, a surge of interest in the community [71][72][73][74] has been seen in the experimental detection of quantum phase transitions using OTOC. At this point our work provides the temporal and spatial features of OTOC to detect a host of different quantum phases which can potentially be implemented in the ongoing experiments.…”

Section: Discussionmentioning

confidence: 99%

Entanglement entropy and out-of-time-order correlator in the long-range Aubry-André-Harper model

Roy,

Sharma

2021

Preprint

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We investigate the nonequilbrium dynamics of entanglement entropy and out-of-time-order correlator (OTOC) of noninteracting fermions at half-filling starting from a product state to distinguish the delocalized, multifractal (in the limit of nearest neighbor hopping), localized and mixed phases hosted by the quasiperiodic Aubry-André-Harper (AAH) model in the presence of long-range hopping. For sufficiently long-range hopping strength a secondary logarithmic behavior in the entanglement entropy is found in the mixed phases whereas the primary behavior is a power-law the exponent of which is different in different phases. The saturation value of entanglement entropy in the delocalized, multifractal and mixed phases depends linearly on system size whereas in the localized phase (in the short-range regime) it is independent of system size. The early-time growth of OTOC shows very different power-law behaviors in the presence of nearest neighbor hopping and long-range hopping. The late time decay of OTOC leads to noticeably different power-law exponents in different phases. The spatial profile of OTOC and its system-size dependence also provide distinct features to distinguish phases. In the mixed phases the spatial profile of OTOC shows two different dependences on space for small and large distances respectively. Interestingly the spatial profile contains large fluctuations at the special locations related to the quasiperiodicity parameter in the presence of multifractal states.

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Section: Discussionmentioning

confidence: 99%

Entanglement entropy and out-of-time-order correlator in the long-range Aubry-André-Harper model

Roy,

Sharma

2021

Preprint

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“…Importantly, it has been shown that both the MQI spectrum and its second moment of MQI are able to capture signatures of quantum phase transitions (QPTs) in many-body quantum systems, also unveiling the role of coherence and entanglement towards the criticality in Hermitian systems [79]. In the following, we will compute the second moment of MQI for several one-dimensional non-Hermitian Hamiltonians that can be engineered with ultracold atoms in optical lattices [27], dissipative Bose-Einstein condensates [86], nuclear spin systems [87], to cite a few.…”

Section: Multiple-quantum Coherencesmentioning

confidence: 99%

“…In a more general scenario, MQC might stand as a bona fide figure of merit to witness phase transitions in non-Hermitian systems. This is motivated by some recent works showing the MQCs testify quantum phase transitions in Hermitian many-body quantum systems [79]. We point out that some recent works have proposed to detect equilibrium phase transitions in non-Hermitian quantum systems by using quantum fidelity and Loschmidt echoes [80][81][82].…”

Section: Introductionmentioning

confidence: 95%

Probing phase transitions in non-Hermitian systems with Multiple Quantum Coherences

Pires,

Macrì

2021

Preprint

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“…In analogy to chaotic classical systems which are characterized by their sensitivity towards small perturbations, OTOCs were originally recognized in high-energy physics literature [2][3][4] as probes of quantum chaos. They are now routinely used as tools to study the dynamics of manybody quantum systems [5][6][7][8][9][10], out-of-equilibrium fluctuations [11][12][13], quantum phase transitions [14][15][16][17][18][19][20][21][22], and to elucidate quantum information spreading in black holes through the AdS/CFT correspondence [2][3][4][23][24][25][26][27].…”

Section: Introductionmentioning

confidence: 99%

Experimental Measurement of Out-of-Time-Ordered Correlators at Finite Temperature

Green,

Elben,

Alderete

et al. 2021

Preprint

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Out-of-time-ordered correlators (OTOCs) are a key observable in a wide range of interconnected fields including many-body physics, quantum information science, and quantum gravity. The ability to measure OTOCs using near-term quantum simulators will extend our ability to explore fundamental aspects of these fields and the subtle connections between them. Here, we demonstrate the first experimental measurement of OTOCs at finite temperatures and study their temperature dependence. These measurements are performed on a digital quantum computer running a simulation of the transverse field Ising model. Our flexible method, based on the creation of a thermofield double state, can be extended to other models and enables us to probe the OTOC's temperaturedependent decay rate. Measuring this decay rate opens up the possibility of testing the fundamental temperature-dependent bounds on quantum information scrambling.

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Detecting Out-of-Time-Order Correlations via Quasiadiabatic Echoes as a Tool to Reveal Quantum Coherence in Equilibrium Quantum Phase Transitions

Cited by 26 publications

References 71 publications

Entanglement entropy and out-of-time-order correlator in the long-range Aubry-André-Harper model

Entanglement entropy and out-of-time-order correlator in the long-range Aubry-André-Harper model

Probing phase transitions in non-Hermitian systems with Multiple Quantum Coherences

Experimental Measurement of Out-of-Time-Ordered Correlators at Finite Temperature

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