`Hot Entanglement' Scrutinized: Effects of Parametric Drive, Squeezing, Instability and non-Markovianity

Galve et al [1] showed that entanglement between two oscillators each interacting with its own bath can be maintained at high temperatures if their coupling is allowed to be time-dependent. In two papers in preparation [2][3], we consider the four key factors which make `hot entanglement’ possible: 1) Instability: Is the dynamically unstable regime used in Galve et al necessary for sustained entanglement? 2) Squeezing: We show that a fixed squeezing is insufficient to sustain entanglement at high temperatures. 3) Parametric drive by time-dependent coupling is necessary. 4) Non-Markovianity: In Galve et al., the baths are Ohmic, with infinite cutoffs at high temperature, thus the dynamics is Markovian. We consider a Lorentzian spectral density function which shows some intriguing behavior in its effect on entanglement.

[1] Galve et al, Phys. Rev. Lett. 105, 180501 (2010).

[2] Onat Arisoy, J. T. Hsiang and B. L. Hu, Effects of nonMarkovian baths on the entanglement dynamics of two coupled quantum oscillators (in preparation)

[3] Onat Arisoy, J. T. Hsiang and B. L. Hu, Hot entanglement? -- Two parametrically coupled quantum oscillators in two heat baths: Effects of Instability, Squeezing and nonMarkovianity (in preparation)