Abstract

The problem of representing a single localized particle has played a crucial role in the historical development of quantum theories. In particular, the failure to construct a relativistically invariant position eigenstate was a contributing factor in the demise of the so-called relativistic quantum mechanics, in favor of quantum field theories. Nevertheless, non-locality which stems from standard accounts of Single-particle localization still presents itself as a problem in the form of Gerhard Hegerfeldt's eponymous theorem of 1974. Accepting that a link may be maintained between invariance and 'objectivity,' it is shown how Hegerfeldt's paradoxical result arises in relativistic theories from a failure of objectivity of localization-the so-called 'Jericho effect'.