"Vacuum-like" Hadamard states for quantum fields on curved spacetimes

Research paper by Marcos Brum, Klaus Fredenhagen

Indexed on: 22 Nov '13Published on: 22 Nov '13Published in: General Relativity and Quantum Cosmology


We present a modification of the recently proposed Sorkin-Johnston states for scalar free quantum fields on a class of globally hyperbolic spacetimes possessing compact Cauchy hypersurfaces. The modification relies on a smooth cutoff of the commutator function and leads always to Hadamard states, in contrast to the original Sorkin-Johnston states. The modified Sorkin-Johnston states are, however, due to the smoothing no longer uniquely associated to the spacetime.