Physical Review Research (Jul 2020)

Single-atom verification of the information-theoretical bound of irreversibility at the quantum level

  • J. W. Zhang,
  • K. Rehan,
  • M. Li,
  • J. C. Li,
  • L. Chen,
  • S.-L. Su,
  • L.-L. Yan,
  • F. Zhou,
  • M. Feng

DOI
https://doi.org/10.1103/PhysRevResearch.2.033082
Journal volume & issue
Vol. 2, no. 3
p. 033082

Abstract

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The quantitative measure of disorder or randomness based on the entropy production characterizes thermodynamical irreversibility, which is relevant to the conventional second law of thermodynamics. Here we report, in a quantum mechanical fashion, the first theoretical prediction and experimental exploration of an information-theoretical bound on the entropy production. Our theoretical model consists of a simplest two-level dissipative system driven by a purely classical field, and under the Markovian dissipation, we find that such an information-theoretical bound, not fully validating quantum relaxation processes, strongly depends on the drive-to-decay ratio and the initial state. Furthermore, we carry out experimental verification of this information-theoretical bound by means of a single spin embedded in an ultracold trapped ^{40}Ca^{+} ion. Our finding, based on a two-level model, is fundamental to any quantum thermodynamical process and indicates much difference and complexity in quantum thermodynamics with respect to the conventionally classical counterpart.