NONLOCALITY, LORENTZ INVARIANCE, AND BOHMIAN QUANTUM-THEORY

We discuss the problem of finding a Lorentz invariant extension of Boh mian mechanics. Due to the nonlocality of the theory there is (for sys tems of more than one particle) no obvious way to achieve such an exte nsion. We present a model invariant under a certain limit of Lorentz t ransformations, a limit retaining the characteristic feature of relati vity, the nonexistence of absolute time, i.e., of simultaneity. The an alysis of this model exemplifies an important property of any Bohmian quantum theory: the quantum equilibrium distribution rho=/psi/(2) cann ot simultaneously be realized in all Lorentz frames of reference.