Closed timelike curves in superfluid He
arXiv:cond-mat/9809140 · doi:10.1016/S0375-9601(98)00709-9
Abstract
It is shown that the curved spacetime induced in a thin film of superfluid He-A by the presence of symmetric vortices with the unbroken symmetry phase, admits the existence of closed timelike curves through which only superfluid clusters formed by anti-He atoms can travel and violate causality.
7 pages, LaTex, to appear in Phys. Lett. A