  It has recently been shown that specific non-perturbative effects may lead to
an explosive decay of flat direction condensates in supersymmetric theories. We
confirm explicitly the efficiency of this process with lattice simulations:
after few rotations of the condensates in their complex plane, most of their
energy is quickly converted into inhomogeneous fluctuations. We then point out
that this generates a gravitational wave background which depends on the
inflaton sector and falls in the Hz-kHz frequency range today. We compute the
resulting spectrum and study how it depends on the parameters. We show that
these gravity waves can be observable by upcoming experiments like Advanced
LIGO and depend crucially on (i) the initial VEV of flat directions when they
start to oscillate, (ii) their soft SUSY-breaking mass and (iii) the reheat
temperature of the universe. This signal could open a new observational window
on inflation and low-energy supersymmetry.
