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Related Experiment Video

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Gradient Echo Quantum Memory in Warm Atomic Vapor
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Reversibility of dynamics and multiple-quantum coherences.

A K Khitrin1

  • 1Department of Chemistry, Kent State University, Kent, Ohio 44242, USA.

Physical Review. E, Statistical, Nonlinear, and Soft Matter Physics
|December 15, 2015
PubMed
Summary

The Loschmidt echo decay in time-reversal experiments is tied to multiple-quantum coherences. This study defines criteria for weak irreversibility in quantum dynamics, applicable beyond spin systems.

Area of Science:

  • Quantum physics
  • Condensed matter physics
  • Statistical mechanics

Background:

  • The Loschmidt echo measures the sensitivity of quantum systems to perturbations.
  • Multiple-quantum (MQ) coherences arise in complex quantum systems and are linked to dynamics.
  • Irreversibility in quantum dynamics is a fundamental concept with implications for thermodynamics.

Purpose of the Study:

  • To establish a link between Loschmidt echo decay and the generation of MQ coherences.
  • To formulate criteria for weak irreversibility in quantum dynamics.
  • To generalize the analysis of quantum dynamics reversibility beyond spin systems.

Main Methods:

  • Analysis of the Loschmidt echo in time-reversal experiments.
  • Investigation of the growth of multiple-quantum coherences.

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  • Formulation of criteria for weak irreversibility based on linear time dependence.

    • Main Results:

    • The decay of the Loschmidt echo is directly related to the generation of MQ coherences.
    • Unlimited growth of MQ coherences leads to irreversible dynamics.
    • Criteria for weak irreversibility are established, characterized by linear time dependence of specific observables.

    Conclusions:

    • The study provides a framework for understanding irreversibility in quantum systems.
    • The proposed approach offers a method to analyze reversibility in many-body quantum dynamics.
    • The findings have potential applications in various quantum systems beyond spins.