Quantum entanglement at high temperatures? Bosonic systems in nonequilibrium steady state

Research output: Contribution to journalArticlepeer-review

7 Scopus citations

Abstract

Abstract: This is the second of a series of three papers examining how viable it is for entanglement to be sustained at high temperatures for quantum systems in thermal equilibrium (Case A), in nonequilibrium (Case B) and in nonequilibrium steady state (NESS) conditions (Case C). The system we analyze here consists of two coupled quantum harmonic oscillators each interacting with its own bath described by a scalar field, set at temperatures T1> T2. For constant bilinear inter-oscillator coupling studied here (Case C1) owing to the Gaussian nature, the problem can be solved exactly at arbitrary temperatures even for strong coupling. We find that the valid entanglement criterion in general is not a function of the bath temperature difference, in contrast to thermal transport in the same NESS setting [1]. Thus lowering the temperature of one of the thermal baths does not necessarily help to safeguard the entanglement between the oscillators. Indeed, quantum entanglement will disappear if any one of the thermal baths has a temperature higher than the critical temperature Tc, defined as the temperature above which quantum entanglement vanishes. With the Langevin equations derived we give a full display of how entanglement dynamics in this system depends on T1, T2, the inter-oscillator coupling and the system-bath coupling strengths. For weak oscillator-bath coupling the critical temperature Tc is about the order of the inverse oscillator frequency, but for strong oscillator-bath coupling it will depend on the bath cutoff frequency. We conclude that in most realistic circumstances, for bosonic systems in NESS with constant bilinear coupling, ‘hot entanglement’ is largely a fiction.

Original languageEnglish
Article number90
Pages (from-to)1-39
Number of pages39
JournalJournal of High Energy Physics
Volume2015
Issue number11
DOIs
StatePublished - 1 Nov 2015

Keywords

  • Quantum Dissipative Systems
  • Stochastic Processes
  • Thermal Field Theory

Fingerprint

Dive into the research topics of 'Quantum entanglement at high temperatures? Bosonic systems in nonequilibrium steady state'. Together they form a unique fingerprint.

Cite this