Quantum Entanglement in Multi-field Inflation

TL;DR

This paper investigates how quantum entanglement develops among multiple fields during inflation, affecting observable perturbations and potentially leaving oscillatory signatures in the power spectrum.

Contribution

It introduces a general formalism for quantifying entanglement between multiple inflaton fields and demonstrates its dynamic emergence in multi-field inflation models.

Findings

Entanglement can dynamically arise between different inflationary fields.

A sudden change in the kinetic matrix induces entanglement and oscillatory features.

The formalism applies in both Heisenberg and Schrödinger pictures.

Abstract

We study the emergence of quantum entanglement in multi-field inflation. In this scenario, the perturbations of one field contribute to the observable curvature perturbation, while multi-field dynamics with the other fields affect the curvature perturbation through particle production and entanglement. We develop a general formalism which defines the quantum entanglement between the perturbations of the multiple fields both in the Heisenberg and Schr\"odinger pictures, and show that entanglement between different fields can arise dynamically in the context of multi-field inflationary scenarios. We also present a simple model in which a sudden change in the kinetic matrix of the scalar fields generates entanglement and an oscillatory feature appears in the power spectrum of the inflaton perturbation.