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arXiv 2302.02700hep-ph
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论Landau-Zener公式对轴子-光子转换的适用性

On the applicability of the Landau-Zener formula to axion-photon conversion

Pierluca Carenza, M. C. David Marsh

AI总结:

本文研究Landau-Zener公式在轴子-光子共振转换中的适用条件,推导了边界位于非均匀性尺度附近的广义LZ公式,揭示了振荡范围小于共振区域时公式失效及绝热极限下转换概率非最大的问题,并提出了互补适用范围的半经典近似方法。

摘要:

轴子与光子在等离子体频率近似等于轴子质量的区域发生共振相互转换。这一过程直接类似于量子力学中的能级免交叉,对此著名的Landau-Zener(LZ)公式为转换概率提供了一个简单的非微扰解。LZ公式在轴子-光子转换研究中被广泛使用;然而,在这一语境下,它依赖于磁场变化远小于等离子体频率变化的假设,而在真实等离子体中这一假设经常不成立。我们通过允许边界位于与非均匀性尺度相近的位置,推导出LZ公式的广义版本。我们发现,当振荡范围与共振区域相比很小时,LZ公式失效。这种失效在绝热极限下更为严重,即当等离子体频率变化缓慢时,所得到的转换概率并非最大,这与直接套用LZ公式的结果相反。此外,我们考虑了广义LZ公式不适用的情形,并提出了一种具有互补适用范围的替代半经典近似。

英文摘要:

Axions and photons resonantly interconvert in regions where the plasma frequency approximately equals the axion mass. This process is directly analogous to an avoided level crossing in quantum mechanics, for which the celebrated Landau-Zener (LZ) formula provides a simple, non-perturbative solution for the conversion probability. The LZ formula is commonly used in studies of axion-photon conversion; however, in this context, it relies on the assumption that the magnetic field variation is small compared to variations of the plasma frequency, which is frequently not the case in real plasmas. We derive a generalised version of the LZ formula by allowing the boundaries to be located at a scale that is similar to the inhomogeneities. We find that the LZ formula fails when the oscillation range is small compared to the resonance region. This failure is more severe in the adiabatic limit, when the plasma frequency varies slowly, resulting in a conversion probability that is not maximal as opposed to a naive application of the LZ formula. Moreover, we consider circumstances where the generalised LZ formula does not apply and present an alternative semi-classical approximation with complementary regime of validity.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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