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The superconducting order parameter and gauge dependence

Claude de Calan·Flavio S. Nogueira
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Abstract

The gauge dependence of the renormalization group functions of the Ginzburg-Landau model is investigated. The analysis is done by means of the Ward-Takahashi identities. After defining the superconducting order parameter, it is shown that its exponent $β$ is in fact gauge independent. This happens because in d=3 the Landau gauge is the only gauge having a physical meaning, a property not shared by the four-dimensional model where any gauge choice is possible. The analysis is done in both the context of the $ε$-expansion and in the fixed dimension approach. It is pointed out the differences that arise in both of these approaches concerning the gauge dependence.

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Claude de Calan, Flavio S. Nogueira. 1999-05-19. The superconducting order parameter and gauge dependence. https://arxiv.org/abs/cond-mat/9905276

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