Probing Planckian physics in de Sitter space with quantum correlations

TL;DR

This paper investigates how Planckian modifications in de Sitter space affect quantum correlations and entanglement, suggesting potential for detecting quantum gravitational effects through quantum information techniques.

Contribution

It introduces a detailed analysis of quantum entanglement degradation in de Sitter space considering Planckian physics and general $oldsymbol{eta}$-vacua, extending beyond single-mode approximations.

Findings

Planckian physics causes additional quantum correlation decrement.

Fermionic entanglement convergence points depend on $oldsymbol{eta}$-vacua.

A link between entanglement negativity convergence and quantum channel capacity zeros.

Abstract

We study the quantum correlation and quantum communication channel of both free scalar and fermionic fields in de Sitter space, while the Planckian modification presented by the choice of a particular $\alpha$-vacuum has been considered. We show that the occurrence of degradation of quantum entanglement between field modes for an inertial observer in curved space, due to the radiation associated with its cosmological horizon. Comparing with standard Bunch-Davies choice, the possible Planckian physics causes some extra decrement on the quantum correlation, which may provide the means to detect quantum gravitational effects via quantum information methodology in future. Beyond single-mode approximation, we construct proper Unruh modes admitting general $\alpha-$vacua, and find a convergent feature of both bosonic and fermionic entanglements. In particular, we show that the convergent points of fermionic entanglement negativity are dependent on the choice of $\alpha$. Moreover, an one-to-one correspondence between convergent points $H_c$ of negativity and zeros of quantum capacity of quantum channels in de Sitter space has been proved.