The evolution of expanding spacetime realizes approximate quantum cloning

TL;DR

This paper explores how the expansion of spacetime affects quantum information, revealing that de Sitter spacetime can approximate quantum cloning due to horizon-induced information loss, linking spacetime curvature to quantum information dynamics.

Contribution

It introduces a model of quantum information evolution in expanding spacetime, demonstrating approximate quantum cloning properties in de Sitter spacetime.

Findings

Quantum channel describing information evolution in de Sitter space

De Sitter spacetime exhibits approximate quantum cloning behavior

Connection established between spacetime curvature and quantum information propagation

Abstract

We investigate how quantum information, encoded in a quantum field, evolves during the expansion of spacetime. Due to information loss across the horizon, a local observer experiences this evolution as a nonunitary quantum channel. We obtain this channel in the case of de Sitter spacetime by assuming the initial global state encodes a signal state via fluctuations of the Bunch-Davies vacuum. Notably, de Sitter evolution exhibits intriguing cloning properties, establishing a connection between the curvature of spacetime and the propagation of quantum information.