论文标题
在空间变化的电磁场中的光子凝结理论
Theory of Photon Condensation in a Spatially-Varying Electromagnetic Field
论文作者
论文摘要
通过量规不变性构成的“无go”定理，禁止实现在空间均匀的量子腔场中平衡量子量相（光子冷凝物）。我们在这里表明，无定理不适用于空间变化的量子腔场。我们发现其发生的标准仅取决于电子系统（ES）的静态，非本地轨道磁化易感性$χ_ {\ rm orb}（q）$。只有3件满足condon不平等的$χ_ {\ rm orb}（q）> 1/（4π）$可以携带光子冷凝。对于嵌入准2D腔中的二维（2D）ESS的实验相关情况，标准再次涉及$χ_ {\ rm orb}（q）$，但也涉及腔的垂直大小。我们使用这些注意事项来识别非常适合光子冷凝的电子特性。我们的理论在电子 - 电子相互作用的强度方面是非扰动的，因此适用于强烈相关的ESS。
The realization of equilibrium superradiant quantum phases (photon condensates) in a spatially-uniform quantum cavity field is forbidden by a "no-go" theorem stemming from gauge invariance. We here show that the no-go theorem does not apply to spatially-varying quantum cavity fields. We find a criterion for its occurrence that depends solely on the static, non-local orbital magnetic susceptibility $χ_{\rm orb}(q)$, of the electronic system (ES) evaluated at a cavity photon momentum $\hbar q$. Only 3DESs satisfying the Condon inequality $χ_{\rm orb}(q)>1/(4π)$ can harbor photon condensation. For the experimentally relevant case of two-dimensional (2D) ESs embedded in quasi-2D cavities the criterion again involves $χ_{\rm orb}(q)$ but also the vertical size of the cavity. We use these considerations to identify electronic properties that are ideal for photon condensation. Our theory is non-perturbative in the strength of electron-electron interaction and therefore applicable to strongly correlated ESs.
