The role of spin in entanglement generated by expanding spacetime

TL;DR

This paper explores how particle spin influences entanglement in Dirac fields within an expanding universe, finding that spin does not significantly alter entanglement behavior except when particles or antiparticles are involved.

Contribution

It introduces a general method to analyze spin effects on entanglement in expanding spacetime, extending previous spinless models.

Findings

Entanglement behavior is similar with or without spin in most cases.

Differences in entanglement arise when particles or antiparticles are present.

Spin does not qualitatively change entanglement generated by spacetime expansion.

Abstract

We investigate the effects of spin on entanglement arising in Dirac field in an expanding spacetime characterized by the Robertson-Walker metric. We present a general approach that allows us to treat the case where only charge conservation is required, as well as the case where also angular momentum conservation is required. We fiend that in both situations entanglement, quantified by subsystem entropy, behaves the same and does not qualitatively deviates from the spinless case. Differences only arise when particles and/or antiparticles are present in the input state.