Quantum field theory for a rotating observer

In the context of the problem of inequivalent quantizations, we study the case of a real massive scalar field in flat space, as perceived by a rotating observer. It is shown that, in the case of uniform rotation, the creation-annihilation operators are the same as those of an inertial observer, while, in the case of nonuniform rotation, a new vacuum state arises which is a superposition of couples of Minkowskian particles with opposite angular momentum along the axis of rotation. Comparison is made with the case of a linearly accelerating observer. (author)