Direct measurement of the two-point function in quantum fields

TL;DR

This paper proposes a method to directly measure the two-point correlation function of quantum fields using bipartite quantum systems, enabling experimental access to the Wightman function's real and imaginary parts.

Contribution

It introduces a novel approach to extract the two-point function in quantum fields through detector statistics, advancing experimental techniques in quantum field theory.

Findings

The detector's measurement statistics encode the two-point correlator of the mediating observable.

The method allows direct experimental evaluation of the Wightman function for various field states.

The approach is applicable to a wide range of quantum field configurations.

Abstract

We analyze fast interaction cycles in bipartite quantum systems, showing that the statistics in one of the parties (the detector) can be used to determine the two-point correlator of the observable which mediates the coupling in the other (the target). We apply the results to the response of particle detectors coupled to quantum fields and subject to this kind of interactions. We show that, in principle, such a setup can be used to experimentally obtain a direct evaluation of the Wightman function (both its real and imaginary part) for any field state.