发表机构
Kobe University; Kyoto University（神户大学; 京都大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究构建了随机磁场中光子向伸缩子等轻粒子转换的演化框架，利用克拉默斯-克朗尼格关系揭示其非幺正演化特性，发现磁螺旋性诱导的光子转换具普适性及双折射等响应。
AI 中文摘要
我们研究由背景磁场诱导的光子向轻粒子（如伸缩子、轴子和引力子）的转换，并通过斯托克斯参量构建其演化过程。研究表明，光子转换可简化为光子扇区的有效非幺正演化；在微扰区域，有效光子哈密顿量的厄米部分与反厄米部分通过克拉默斯-克朗尼格关系关联，揭示斯托克斯参量的变化并非独立。我们将该通用框架应用于具有可能螺旋性的高斯随机磁场中的光子演化，推导斯托克斯参量的系综平均演化，发现即便无磁螺旋性，也会产生两个非零贡献：分别对应所有斯托克斯参量的整体衰减和无关紧要的整体相位。同时发现，磁螺旋性会产生两个额外贡献：一个改变圆偏振，另一个诱导线偏振旋转，这些贡献构成两对克拉默斯-克朗尼格关系；特别地，磁螺旋性诱导的光子转换伴随圆偏振和双折射响应，该结构同样出现在伸缩子-光子、轴子-光子及引力子-光子系统中，揭示磁场中光子转换的普适性。
英文摘要
We study photon conversion into light particles, such as dilatons, axions, and gravitons, induced by background magnetic fields, and formulate the resulting evolution in terms of the Stokes parameters. We show that photon conversion reduces to an effective non-unitary evolution of the photon sector. In the perturbative regime, the Hermitian and anti-Hermitian parts of the effective photon Hamiltonian are related through Kramers--Kronig relations, revealing that the changes in the Stokes parameters are not independent. We apply this general framework to photon evolution in Gaussian stochastic magnetic fields with possible helicity, and derive the ensemble-averaged evolution of the Stokes parameters. We find that two nonzero contributions arise even in the absence of magnetic helicity, which respectively correspond to the overall attenuation of all the Stokes parameters and to an irrelevant overall phase. We also find that magnetic helicity gives rise to two additional contributions, one of which changes the circular polarization while the other induces a rotation of linear polarization. These contributions form two Kramers--Kronig pairs. In particular, photon conversion induced by magnetic helicity is accompanied by both circular-polarization and birefringent responses. The same structure appears in dilaton-photon, axion-photon, and graviton-photon systems, revealing universality of photon conversion in magnetic fields.
Comments22 pages, 2 figures
