摘要： A bstract 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 T 1 > T 2 . 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 T c , 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 T 1 , T 2 , the inter-oscillator coupling and the system-bath coupling strengths. For weak oscillator-bath coupling the critical temperature T c 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. 其他題名： J. High Energ. Phys 出版者： Berlin/Heidelberg: Springer Berlin Heidelberg 出版日期： 2015-11-01 出處： The journal of high energy physics, 2015-11, Vol.2015 (11), p.1-39, Article 90 資源來源： Publicly Available Content Database 版權： The Author(s) 2015 版權： SISSA, Trieste, Italy 2015 識別號： ISSN: 1029-8479 識別號： ISSN: 1126-6708 識別號： ISSN: 1127-2236 識別號： EISSN: 1029-8479 識別號： DOI: 10.1007/JHEP11(2015)090
