Effective action approach to the Leggett's mode in two-band superconductors
arXiv:cond-mat/0205131 · doi:10.1140/epjb/e2002-00356-9
Abstract
We investigate a collective excitation (Leggett's mode) corresponding to small fluctuations of the relative phase of two condensates in two-band superconductor using the effective ``phase only'' action. We consider the possibility of observing Leggett's mode in MgB$_2$ superconductor and conclude that for the known at present values of the two-band model parameters for MgB$_2$ Leggett's mode arises above the two-particle threshold.
9 pages, RevTeX4; final version published in EPJB