Superconducting phase transition and gauge dependence

Claude de Calan; Flavio S. Nogueira

doi:10.1103/PhysRevB.60.11929

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Superconducting phase transition and gauge dependence

Claude de Calan, Flavio S. Nogueira

DOI 10.1103/PhysRevB.60.11929 · Physical Review B

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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 local 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.