标题： 原子系综在非均匀原子-光相互作用下的纠缠集体自旋态 显示英文标题

标题： Entangled collective-spin states of atomic ensembles under non-uniform atom-light interaction

摘要： 我们考虑在原子系综与光学模式之间存在非均匀相互作用的情况下，光子生成和验证纠缠。 我们表明，在广泛的参数范围内，非均匀耦合的原子自旋系统可以描述为具有减少的有效原子-光耦合和减少的有效原子数的均匀耦合自旋系综，减少因子由系综-模式几何结构给出，数量级为一。 只要检测不分辨单个自旋，这种描述对于具有任意相空间分布函数的复杂纠缠态也是有效的。 此外，我们推导出在实际相关情况下可观测纠缠的解析公式，此时系综-模式耦合在状态生成和测量之间有所不同。 显示英文摘要

摘要： We consider the optical generation and verification of entanglement in atomic ensembles under non-uniform interaction between the ensemble and an optical mode. We show that for a wide range of parameters a system of non-uniformly coupled atomic spins can be described as an ensemble of uniformly coupled spins with a reduced effective atom-light coupling and a reduced effective atom number, with a reduction factor of order unity given by the ensemble-mode geometry. This description is valid even for complex entangled states with arbitrary phase-space distribution functions as long as the detection does not resolve single spins. Furthermore, we derive an analytic formula for the observable entanglement in the case, of relevance in practice, where the ensemble-mode coupling differs between state generation and measurement.