Reexamination of Quenches in4He(and3He)

In the light of recent difficulties in observing vortices in quenches of liquid ${}^4\mathrm{He}$ to its superfluid state, we reexamine the Zurek scenario for their production. We argue that experiments in ${}^4\mathrm{He}$ are unlikely to produce true vortices in the numbers originally anticipated, if at all, because of the wide Ginzberg regime and the slowness of the mechanical quenches. On the other hand, the observed production of unambiguous vortices in neutron-bombarded ${}^3\mathrm{He}$, with its narrow Ginzburg regime and fast quenches, is to be expected.