论文标题
避免腔Qed中的歧义
Avoiding gauge ambiguities in cavity QED
论文作者
论文摘要
相互作用的电荷和磁场的系统在物理学中无处不在。最近，已经表明，当物质的自由度被截断为一些低洼的能量特征状态时，使用不同仪表衍生的哈密顿人可以产生不同的身体结果。这种效应在超强耦合方面尤为突出。这种歧义之所以出现，是因为转换改组了光和物质自由度之间的划分，因此水平的截断是依赖于尺寸的估计近似值。为了避免这种规格的歧义，我们根据该理论的量规选择明确地重新定义了电磁场的潜在磁场。取而代之的是，光/物质分区是通过直观的选择在位移和极化贡献之间分离电场的直观选择。在典型的空腔量子电动力学情况下，这种方法是一个有吸引力的选择。
Systems of interacting charges and fields are ubiquitous in physics. Recently, it has been shown that Hamiltonians derived using different gauges can yield different physical results when matter degrees of freedom are truncated to a few low-lying energy eigenstates. This effect is particularly prominent in the ultra-strong coupling regime. Such ambiguities arise because transformations reshuffle the partition between light and matter degrees of freedom and so level truncation is a gauge dependent approximation. To avoid this gauge ambiguity, we redefine the electromagnetic fields in terms of potentials for which the resulting canonical momenta and Hamiltonian are explicitly unchanged by the gauge choice of this theory. Instead the light/matter partition is assigned by the intuitive choice of separating an electric field between displacement and polarisation contributions. This approach is an attractive choice in typical cavity quantum electrodynamics situations.
