New techniques for entanglement harvesting in flat and curved spacetimes

TL;DR

This paper introduces a novel computational technique for entanglement harvesting using Unruh-DeWitt detectors, simplifying calculations especially in complex spacetime scenarios, and provides new analytical solutions in Minkowski space.

Contribution

The authors develop a new method exploiting Wightman function symmetry to simplify entanglement calculations, enabling analytical solutions previously unavailable.

Findings

Analytical solution for entanglement harvesting in Minkowski space.

Simplified computation method reduces numerical cost.

Applicable to flat and curved spacetimes with known mode expansions.

Abstract

We present a new technique for computing entanglement harvesting with Unruh-DeWitt particle detectors. The method is particularly useful in cases where analytic solutions are rare and the Wightman function is known only via its mode expansion for which numerical integration can become very expensive. By exploiting the conjugate symmetry of the Wightman function, we may split the integral into parts dependent on the commutator and anti-commutator of the field. In cases where the commutator vanishes, such as spacelike separation, or timelike separation if the strong Huygens principle holds, we then show that the entangling term of the bipartite density matrix can be expressed in terms of the much simpler mutual information term. For the vacuum state, this can be translated into a simple Fourier transform, and thus a single sum over modes, simplifying the procurement of closed expressions. We demonstrate this for Minkowski space, finding an analytical solution where none was previously known.