Abstract:
Within the renormalization-group framework we study the stability of superfluid density wave states, known as Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) phases, with respect to thermal order-parameter fluctuations in two-and three-dimensional (d is an element of{2,3}) systems. We analyze the renormalization-group flow of the relevant ordering wave vector (Q) over right arrow (0). The calculation indicates an instability of the FFLO-type states towards either a uniform superfluid or the normal state in d is an element of{2,3} and T > 0. In d = 2 this is signaled by (Q) over right arrow (0) being renormalized towards zero, corresponding to the flow being attracted either to the usual Kosterlitz-Thouless fixed point or to the normal phase. We supplement a solution of the RG flow equations by a simple scaling argument, supporting the generality of the result. The tendency to reduce the magnitude of (Q) over right arrow (0) by thermal fluctuations persists in d = 3, where the very presence of long-range order is immune to thermal fluctuations, but the effect of attracting (Q) over right arrow (0) towards zero by the flow remains observed at T > 0.