Effects of acceleration on interatomic interactions

TL;DR

This paper explores how uniform acceleration affects interatomic electromagnetic interactions, revealing new off-diagonal components and deviations from inertial behavior, challenging the Unruh effect's equivalence between acceleration and thermality.

Contribution

It demonstrates that acceleration introduces unique off-diagonal interaction components and modifies the scaling of van der Waals and Casimir-Polder forces, especially at high accelerations.

Findings

Off-diagonal interaction components arise solely due to acceleration.

At small accelerations, interaction scaling remains similar to inertial cases.

High accelerations significantly alter interaction behaviors, breaking the acceleration-thermality equivalence.

Abstract

The Unruh effect establishes a fundamental equivalence between acceleration and thermality by demonstrating that a uniformly accelerated ground-state detector undergoes excitation as if immersed in a thermal bath. In this paper, we investigate how acceleration influences the interaction between two ground-state atoms that are synchronously and uniformly accelerated in vacuum with proper acceleration $a$ and coupled to a fluctuating electromagnetic field. We find that the resulting interaction potential comprises both diagonal components $(\delta E)^{jk}$ with $j=k$, which are present in both inertial and acceleration cases, and off-diagonal components $(\delta E)^{jk}$ with $j\neq k$, which arise exclusively due to acceleration and vanish in the inertial case. The dependence of each component on acceleration and interatomic separation $L$ generally differs. For small accelerations, the leading-order diagonal components of the van der Waals (vdW) and Casimir-Polder (CP) interaction potentials remain unchanged from their inertial counterparts, exhibiting the standard scaling behaviors $\sim L^{-6}$ and $\sim L^{-7}$, respectively. In contrast, the off-diagonal components scale as $\sim a^2L^{-4}$ in the vdW subregions and $\sim a^2L^{-5}$ in the CP subregion. However, when the acceleration becomes sufficiently large, both diagonal and off-diagonal components of the vdW and CP interaction potentials are significantly modified, giving rise to entirely new interaction behaviors that deviate from those observed in the inertial case, whether in vacuum or thermal environments, indicating a breakdown of the acceleration-thermality equivalence established by the Unruh effect for single detectors.