AI 中文总结
该研究针对真空电磁涨落能否提高超导转变温度的问题，通过金兹堡-朗道理论推导得出无源腔下真空涨落抑制超导性的禁区定理，并提出突破该约束的两条实现腔增强超导性的路径。
AI 中文摘要
近期报道的腔真空改性超导性实验提出了一个基本问题：在何种条件下，真空电磁涨落能提高超导转变温度？我们从与量子化腔模最小耦合的金兹堡-朗道理论出发，推导了腔诱导的超导自由能重整化，该修正包含正的抗磁贡献和负的顺磁交换贡献。我们证明，在无源腔中，后者无法超过前者，从而确立了一个禁区定理：在最小腔电动力学框架内，真空涨落会抑制而非增强超导性。随后，我们确定了突破该约束的两条路径，均涉及额外的集体自由度：在集体模路径中，腔活性激发会放大吸引性的顺磁贡献；在竞争序路径中，腔会削弱与超导竞争的序，从而间接增强超导性。这些结果共同将禁区定理转化为实用设计原则：腔超导性增强需要额外的腔耦合材料模，该模要么增强顺磁交换，要么抑制竞争序。
英文摘要
Recent experiments reporting cavity-vacuum-modified superconductivity raise a fundamental question: under what conditions can vacuum electromagnetic fluctuations increase a superconducting transition temperature? Starting from a Ginzburg--Landau theory minimally coupled to a quantized cavity mode, we derive the cavity-induced renormalization of the superconducting free energy. This correction comprises a positive diamagnetic contribution and a negative paramagnetic exchange contribution. We prove that, in a passive cavity, the latter cannot exceed the former, establishing a no-go theorem: within minimal cavity electrodynamics, vacuum fluctuations suppress, rather than enhance, superconductivity. We then identify two routes beyond this constraint, both involving additional collective degrees of freedom. In the collective-mode route, a cavity-active excitation amplifies the attractive paramagnetic contribution. In the competing-order route, the cavity weakens an order that competes with superconductivity, thereby indirectly enhancing superconductivity. Together, these results turn the no-go theorem into a practical design principle: cavity superconductivity enhancement requires an additional cavity-coupled material mode that either strengthens paramagnetic exchange or suppresses a competing order.
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