Bath-induced coherence and the secular approximation

P. R. Eastham, P. Kirton, H. M. Cammack, B. W. Lovett, J. Keeling

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Abstract

Finding efficient descriptions of how an environment affects a collection of discrete quantum systems would lead to new insights into many areas of modern physics. Markovian, or time-local, methods work well for individual systems, but for groups a question arises: Does system-bath or intersystem coupling dominate the dissipative dynamics? The answer has profound consequences for the long-time quantum correlations within the system. We consider two bosonic modes coupled to a bath. By comparing an exact solution against different Markovian master equations, we find that a smooth crossover of the equations of motion between dominant intersystem and system-bath coupling exists - but it requires a nonsecular master equation. We predict singular behavior of the dynamics and show that the ultimate failure of nonsecular equations of motion is essentially a failure of the Markov approximation. Our findings support the use of time-local theories throughout the crossover between system-bath-dominated and intersystem-coupling-dominated dynamics.

Original languageEnglish
Article number012110
Number of pages9
JournalPhysical Review A
Volume94
Issue number1
DOIs
Publication statusPublished - 19 Jul 2016

Keywords

  • bosonic modes
  • bath
  • Markovian master equations

Cite this

Eastham, P. R., Kirton, P., Cammack, H. M., Lovett, B. W., & Keeling, J. (2016). Bath-induced coherence and the secular approximation. Physical Review A, 94(1), [012110]. https://doi.org/10.1103/PhysRevA.94.012110