  We study the gravitational wave signals emitted from phase-transition induced
collapses of rapidly rotating neutron stars to strange stars by performing 3D
numerical simulations. Our preliminary results suggest that the complete
conversion of neutron stars to strange stars would occur within a fraction of
millisecond. We also find that the gravitational waves generated from the
collapse process may be detectable by the advanced LIGO for reasonable source
distance. In addition, the study such gravitational wave signals would put
useful constraint on the parameters of QCD.
