Quantum information and the C-theorem in de Sitter

TL;DR

This paper extends information-theoretic methods to quantum field theories in de Sitter space, deriving a C-theorem and entropy bounds, thus advancing nonperturbative analysis in curved spacetime.

Contribution

It generalizes flat space information-theoretic inequalities to de Sitter space, establishing a C-theorem and entropy bounds for 1+1-dimensional field theories.

Findings

Derived a boosted strong subadditivity inequality in de Sitter.

Proved a C-theorem for RG flows in de Sitter.

Established Lorentzian bounds on entanglement and thermal entropies.

Abstract

Information-theoretic methods have led to significant advances in nonperturbative quantum field theory in flat space. In this work, we show that these ideas can be generalized to field theories in a fixed de Sitter space. Focusing on 1+1-dimensional field theories, we derive a boosted strong subadditivity inequality in de Sitter, and show that it implies a C-theorem for renormalization group flows. Additionally, using the relative entropy, we establish a Lorentzian bound on the entanglement and thermal entropies for a field theory inside the static patch. Finally, we discuss possible connections with recent developments using unitarity methods.