Out-of-time-ordered correlation functions in open systems: A Feynman-Vernon influence functional approach

@article{Tuziemski2019OutoftimeorderedCF,
  title={Out-of-time-ordered correlation functions in open systems: A Feynman-Vernon influence functional approach},
  author={Jan Tuziemski},
  journal={Physical Review A},
  year={2019}
}
Recent theoretical and experimental studies have shown the significance of quantum information scrambling (i.e., the spread of quantum information over a system's degrees of freedom) for problems e ... 
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THE GENERALIZED OTOC FROM SUPERSYMMETRIC QUANTUM MECHANICS: Study of Random Fluctuations from Eigenstate Representation of Correlation Functions
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It is demonstrated that the evolution of complexity is a possible diagnostic of chaos through explicit calculations on a toy model of two coupled harmonic oscillators, where one or both of the oscillators are inverted.
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Unitary circuits subject to repeated projective measurements can undergo an entanglement transition as a function of the measurement rate. This transition is generally understood in terms of a…
Information Scrambling and Loschmidt Echo.
TLDR
Analytically and numerically, the out-of-time order correlator is demonstrated to be given by the thermal average of Loschmidt echo signals, a well-appreciated familiar diagnostic that captures the dynamical aspect of chaotic behavior in the time domain and is accessible to experimental studies.
Out-of-time-order correlations in the quasiperiodic Aubry-André model
We study out-of-time-ordered correlators (OTOC) in a free fermionic model with a quasiperiodic potential. This model is equivalent to the Aubry-Andr\'e model and features a phase transition from an…
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Classical quasi-integrable systems are known to have Lyapunov times much shorter than their ergodicity time, but the situation for their quantum counterparts is less well understood. As a first…
Quasi-integrable systems are slow to thermalize but may be good scramblers.
TLDR
The quantum Lyapunov exponent, defined by the evolution of the four-point out-of-time-order correlator (OTOC), of integrable systems which are weakly perturbed by an external noise is examined, a setting that has proven to be illuminating in the classical case.
Scaling at the OTOC Wavefront: Integrable versus chaotic models
Out of time ordered correlators (OTOCs) are useful tools for investigating foundational questions such as thermalization in closed quantum systems because they can potentially distinguish between…

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