Geometric phase of two-level atoms and thermal nature of de Sitter spacetime

TL;DR

This paper investigates how the geometric phase of two-level atoms in de Sitter spacetime reveals its thermal nature, with corrections influenced by the Gibbons-Hawking temperature and Unruh effect, highlighting observable and non-observable regimes.

Contribution

It demonstrates the thermal effects on geometric phase in de Sitter spacetime for both freely falling and static atoms, linking quantum phases to spacetime thermal properties.

Findings

Freely falling atom's geometric phase correction is too small to measure.

Static atom's phase correction becomes observable near the horizon.

Thermal nature of de Sitter spacetime affects quantum phases of atoms.

Abstract

In the framework of open quantum systems, we study the geometric phase acquired by freely falling and static two-level atoms interacting with quantized conformally coupled massless scalar fields in de Sitter-invariant vacuum. We find that, for the freely falling atom, the geometric phase gets a correction resulting from a thermal bath with the Gibbons-Hawking temperature, thus it clearly reveals the intrinsic thermal nature of de Sitter spacetime from a different physical context. For the static atom, there is a correction to the geometric phase coming from both the intrinsic thermal nature of de Sitter spacetime and the Unruh effect associated with the proper acceleration of the atom. Furthermore, in a gedanken experiment, we estimate the magnitude of the correction to the geometric phase as opposed to that in a flat spacetime. We find that the correction for the freely falling atom is too tiny to be measured, and that for the static atom achieves an observable magnitude only when the atom almost locates at the horizon.