Low-energy phase-only action in a superconductor: A comparison with the XY model (Articolo in rivista)

Type
Label
  • Low-energy phase-only action in a superconductor: A comparison with the XY model (Articolo in rivista) (literal)
Anno
  • 2004-01-01T00:00:00+01:00 (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#doi
  • 10.1103/PhysRevB.69.184510 (literal)
Alternative label
  • L. Benfatto (1,2); A. Toschi (1); S. Caprara (1) (2004)
    Low-energy phase-only action in a superconductor: A comparison with the XY model
    in Physical review. B, Condensed matter and materials physics
    (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#autori
  • L. Benfatto (1,2); A. Toschi (1); S. Caprara (1) (literal)
Pagina inizio
  • 184510 (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#url
  • http://prb.aps.org/abstract/PRB/v69/i18/e184510 (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#numeroVolume
  • 69 (literal)
Rivista
Note
  • ISI Web of Science (WOS) (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#affiliazioni
  • (1) Dipartimento di Fisica, Università di Roma \"La Sapienza,\" and Istituto Nazionale per la Fisica della Materia (INFM)-SMC and Unità di Roma 1, Piazzale Aldo Moro, 2--I-00185 Roma, Italy (2) Département de Physique, Université de Fribourg, Chemin du Musée, 3--CH-1700 Fribourg, Switzerland (literal)
Titolo
  • Low-energy phase-only action in a superconductor: A comparison with the XY model (literal)
Abstract
  • The derivation of the effective theory for the phase degrees of freedom in a superconductor is still, to some extent, an open issue. It is commonly assumed that the classical XY model and its quantum generalizations can be exploited as effective phase-only models. In the quantum regime, however, this assumption leads to spurious results, such as the violation of Galilean invariance in the continuum model. Starting from a general microscopic model, in this paper we explicitly derive the effective low-energy theory for the phase, up to fourth-order terms. This expansion allows us to properly take into account dynamic effects beyond the Gaussian level, both in the continuum and in the lattice model. After evaluating the one-loop corrections to the superfluid stiffness we critically discuss the qualitative and quantitative differences between the results obtained within the quantum XY model and within the correct low-energy theory, both in the case of s- and d-wave symmetry of the superconducting order parameter. Specifically, we find dynamic anharmonic vertices, which are absent in the quantum XY model, and are crucial to restore Galilean invariance in the continuum model. As far as the more realistic lattice model is concerned, in the weak-to-intermediate-coupling regime we find that the phase-fluctuation effects are quantitatively reduced with respect to the XY model. On the other hand, in the strong-coupling regime we show that the correspondence between the microscopically derived action and the quantum XY model is recovered, except for the low-density regime. (literal)
Autore CNR

Incoming links:


Autore CNR di
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#rivistaDi
data.CNR.it