The Unruh effect in general boundary quantum field theory

We present an analysis of the Unruh effect from the perspective of the general boundary formulation of the quantum field theory of a massive scalar field in Minkowski and Rindler spacetimes. We underline the difficulty in identifying the Minkowski vacuum state with a superposition of multiparticle states defined in the double Rindler wedge. However, in contrast to this "global" version of the Unruh effect we show that a "local" version of it arises when comparing expectation values of observables quantized with the Feynman quantization prescription that have compact support restricted to one of the Rindler wedges. We find that even this notion of local Unruh effect does not exist when the same observables are quantized according to the Berezin-Toeplitz quantization scheme