标题： 耗散耦合辅助激光冷却：限制与前景 显示英文标题

标题： Dissipative-coupling-assisted laser cooling: limitations and perspectives

摘要： 最近在未分辨边带区域通过结合耗散和色散光机械耦合，在红色边带激发下实现机械振荡器基态冷却的可能性被发现[Phys. Rev. A 88, 023850 (2013)]，目前被视为一个显著的发现。我们对该协议进行了全面分析，揭示了其对小缺陷的极高敏感性，例如额外的耗散、优化实验设置的不准确性和所采用理论框架的不准确性。这些缺陷对冷却极限的影响被定量评估。发现内部腔体衰减率对冷却极限有非常显著的影响，即使该衰减率相对于检测率来说很小，也可能大幅提高该极限，从而质疑基态冷却的可能性。具体而言，只有当内部衰减率与检测率的比值远小于该协议预测的冷却极限与常见色散耦合辅助边带冷却极限的比值时，内部损耗才可以被忽略。此外，我们确定该协议理论适用性的条件是后者比值远小于一。还详细比较了该冷却协议与使用红色边带激发或反馈的色散耦合辅助协议。 显示英文摘要

摘要： The recently identified possibility of ground-state cooling of a mechanical oscillator in the unresolved sideband regime by combination of the dissipative and dispersive optomechanical coupling under the red sideband excitation [Phys. Rev. A 88, 023850 (2013)], is currently viewed as a remarkable finding. We present a comprehensive analysis of this protocol, which reveals its very high sensitivity to small imperfections such as an additional dissipation, the inaccuracy of the optimized experimental settings, and the inaccuracy of the theoretical framework adopted. The impact of these imperfections on the cooling limit is quantitatively assessed. A very strong effect on the cooling limit is found from the internal cavity decay rate which even being small compared with the detection rate may drastically push that limit up, questioning the possibility of the ground state cooling. Specifically, the internal loss can only be neglected if the ratio of the internal decay rate to the detection rate is much smaller than the ratio of the cooling limit predicted by the protocol to the common dispersive-coupling assisted sideband cooling limit. More over, we establish that the condition of applicability of theory of that protocol is the requirement that the latter ratio is much smaller than one. A detailed comparison of the cooling protocol in question with the dispersive-coupling-assisted protocols which use the red sideband excitation or feedback is presented.