We present a study on how to realize the widely interested optomechanicalentanglement at high temperature. Unlike the majority of the previousexperimental and theoretical researches that consider the entanglement of amechanical resonator with a cavity field created by red-detuned continuous-waveor blue-detuned pulsed driving field, we find that applying blue-detunedcontinuous-wave pump field to cavity optomechanical systems can achieveconsiderable degrees of quantum entanglement, which is generally challenging toobtain at high temperature for the known physical systems. The competitionbetween the induced squeezing-type interaction and the existing decoherenceleads to stable entanglement in dynamically unstable regime. There is a muchmore relaxed condition for the existence of entanglement, as compared with thewell-known criterion for neglecting the thermal decoherence on optomechanicallycoupled systems. A simple relation about a boundary in the parameter space,across which the entanglement can exist or not, is found with an analyticalexpression for the degree of the achieved entanglement at any temperature,which is derived for the systems of highly resolved sideband. The studiedscenario with blue-detuned continuous-wave driving field can greatly simplifythe generation of the widely interested optomechanical entanglement ofmacroscopic quantum states. Our study also provides the answers to twofundamentally meaningful open problems: (1) what is the condition for a systemto avoid its loss of quantum entanglement under thermal decoherence? (2) is itpossible to preserve the entanglement in a thermal environment by increasingthe interaction that entangles the subsystems?
展开▼
