  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 ($d\in \{2,3\}$) systems. We analyze the
renormalization-group flow of the relevant ordering wave-vector $\vec{Q_0}$.
The calculation indicates an instability of the FFLO-type states towards either
a uniform superfluid or the normal state in $d\in\{2,3\}$ and $T>0$. In $d=2$
this is signaled by $\vec{Q_0}$ 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 $\vec{Q_0}$ 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 $\vec{Q_0}$ towards zero by the flow
remains observed at $T>0$.
