论文标题
量子状态纯度与平均声子编号用于腔光力学中机械振荡器的表征
Quantum state purity versus average phonon number for characterization of mechanical oscillators in cavity optomechanics
论文作者
论文摘要
高斯州中的量子振荡器通常以平均职业数量为特征，这些数字是指非相互作用振荡器哈密顿量的基础。我们认为，量子状态纯度是此类状态的更合适的特征，可以应用于任何维度的振荡器。对于一维振荡器，状态纯度与相对于振荡器量子状态为热状态的数量状态基础定义的热职业数直接相关。因此，它自然会引入平均职业人数的更广泛的定义。我们尤其是一维机械振荡器的光学机械边带冷却，并在量子背性极限中获得可实现的最大机械状态纯度的精确分析表达式。在一维振荡器的情况下，我们表明，与纯度相关的热职业数量可以通过弱偶联体系中的平均声子数很好地近似，但是在振荡器的振荡频率强烈恢复恢复正常的情况下，超局部光学机电偶联或在Ultrastrong OptoRogion偶联方案中的两个差异。
Quantum oscillators in Gaussian states are often characterized by average occupation numbers that refer to a basis of eigenstates of the non-interacting oscillator Hamiltonian. We argue that quantum state purity is a more appropriate characteristic of such states, which can be applied to oscillators of any dimensionality. For a one-dimensional oscillator, the state purity is directly related to a thermal occupation number defined with respect to the number state basis in which the oscillator's quantum state is thermal. Thus, it naturally introduces a more versatile definition of an average occupation number. We study optomechanical sideband cooling of one- and two-dimensional mechanical oscillators in particular, and derive exact analytical expressions for the maximal mechanical state purity achievable in the quantum backaction limit. In the case of a one-dimensional oscillator, we show that the thermal occupation number related to purity can be well approximated by the average phonon number in the weak-coupling regime, but that the two differ in the regime of ultrastrong optomechanical coupling or in cases where the oscillator's resonance frequency is strongly renormalized.
