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arXiv · 1806.08967

Gauge Invariance beyond the Electric Dipole Approximation

Ryoji Anzaki·Yasushi Shinohara·Takeshi Sato·Kenichi L. Ishikawa
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Abstract

We study the gauge invariance of laser-matter interaction. The velocity gauge where the vector potential is expanded to the $n$-th order with respect to the spatial coordinate, and the length gauge where the electric and magnetic fields are expanded to the $n$-th and $(n-1)$-th orders, respectively, are mutually gauge-transformed, describing the physically equivalent situation. The latter includes up to the electric $2^{n+1}$-pole and magnetic $2^n$-pole interactions as well as two extra terms. The finding serves to develop consistent nonperturbative simulation methods beyond the electric dipole approximation.

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Ryoji Anzaki, Yasushi Shinohara, Takeshi Sato, Kenichi L. Ishikawa. 2018-11-18. Gauge Invariance beyond the Electric Dipole Approximation. https://doi.org/10.1103/physreva.98.063410

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