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arXiv 0911.0640hep-th
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从因果关系导出非线性电动力学中有效拉格朗日量的凸性

Convexity of effective Lagrangian in nonlinear electrodynamics as derived from causality

Anatoly E. Shabad, Vladimir V. Usov

摘要:

在非线性电动力学中,通过实施因果性原理作为背景场上基本激发的群速度不应超过1的要求,以及作为传播子的留数应是非负的要求的幺正性原理,我们发现了对有质量和无质量色散曲线的行为的限制,并建立了常数场类上有效拉格朗日量的凸性,也是所有特征介电常数和磁介电常数的正性。本文分析了在指数大磁场下QED中单圈近似违反一般原理而产生的复杂能量快子和超光速鬼波,它们是磁化真空不稳定性的信号。讨论了光子分裂/合并过程中运动学选择规则的一般依据。

英文摘要:

In nonlinear electrodynamics, by implementing the causality principle as the requirement that the group velocity of elementary excitations over a background field should not exceed unity, and the unitarity principle as the requirement that the residue of the propagator should be nonnegative, we find restrictions on the behavior of massive and massless dispersion curves and establish the convexity of the effective Lagrangian on the class of constant fields, also the positivity of all characteristic dielectric and magnetic permittivity constants. Violation of the general principles by the one-loop approximation in QED at exponentially large magnetic field is analyzed resulting in complex energy tachyons and super-luminal ghosts that signal the instability of the magnetized vacuum. General grounds for kinematical selection rules in the process of photon splitting/merging are discussed.

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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