# Van der Waals and resonance interactions between accelerated atoms in vacuum and the Unruh effect

## TL;DR

This paper investigates how uniform acceleration affects atomic interactions in vacuum, revealing nonthermal effects and potential methods to indirectly detect the Unruh effect through changes in van der Waals and resonance forces.

## Contribution

It demonstrates that acceleration alters atomic dispersion and resonance interactions, challenging the temperature-acceleration equivalence and proposing new ways to observe the Unruh effect.

## Key findings

- Acceleration modifies the scaling of van der Waals forces with distance.
- Nonthermal effects influence resonance interactions between accelerated atoms.
- The Unruh temperature assumption is not necessary in the coaccelerated frame for equivalence.

## Abstract

We discuss different physical effects related to the uniform acceleration of atoms in vacuum, in the framework of quantum electrodynamics. We first investigate the van der Waals/Casimir-Polder dispersion and resonance interactions between two uniformly accelerated atoms in vacuum. We show that the atomic acceleration significantly affects the van der Waals force, yielding a different scaling of the interaction with the interatomic distance and an explicit time dependence of the interaction energy. We argue how these results could allow for an indirect detection of the Unruh effect through dispersion interactions between atoms. We then consider the resonance interaction between two accelerated atoms, prepared in a correlated Bell-type state, and interacting with the electromagnetic field in the vacuum state, separating vacuum fluctuations and radiation reaction contributions, both in the free-space and in the presence of a perfectly reflecting plate. We show that nonthermal effects of acceleration manifest in the resonance interaction, yielding a change of the distance dependence of the resonance interaction energy. This suggests that the equivalence between temperature and acceleration does not apply to all radiative properties of accelerated atoms. To further explore this aspect, we evaluate the resonance interaction between two atoms in non inertial motion in the coaccelerated (Rindler) frame and show that in this case the assumption of an Unruh temperature for the field is not required for a complete equivalence of locally inertial and coaccelerated points of views.