The Unruh effect in quantum information beyond the single-mode approximation

Abstract

We address the validity of the single-mode approximation that is commonly invoked in the analysis of entanglement in non-inertial frames and in other relativistic quantum information scenarios. We show that the single-mode approximation is not valid for arbitrary states, finding corrections to previous studies beyond such approximation in the bosonic and fermionic cases. We also exhibit a class of wave packets for which the single-mode approximation is justified subject to the peaking constraints set by an appropriate Fourier transform.

revtex4, 3 figures, I.F. previously published as Fuentes-Guridi and Fuentes-Schuller. Minor changes and Journal reference added