Gauge dependence of the order parameter anomalous dimension in the Ginzburg-Landau model and the critical fluctuations in superconductors
Abstract
The critical fluctuations of superconductors are discussed in a fixed dimension scaling suited to describe the type-II regime. The gauge dependence of the anomalous dimension of the scalar field is established exactly from the Ward-Takahashi identities. Its fixed-point value gives the η critical exponent and it is shown that η is gauge independent, as expected on physical grounds. In the scaling considered, η is found to be zero at 1-loop order, while ν approx 0.63. This result is just the 1-loop values for the XY model obtained in the fixed-dimension renormalization group approach. It is shown that this XY behavior holds at all orders. The result η = ηXY should be contrasted with the negative values frequently reported in the literature.
- Publication:
-
EPL (Europhysics Letters)
- Pub Date:
- March 1999
- DOI:
- 10.1209/epl/i1999-00211-3
- arXiv:
- arXiv:cond-mat/9808097
- Bibcode:
- 1999EL.....45..612N
- Keywords:
-
- 74.20.De;
- 11.10.Hi;
- Phenomenological theories;
- Renormalization group evolution of parameters;
- Condensed Matter - Superconductivity
- E-Print:
- EuroLaTex, 7 pages, 2 figures, reference updated