Application of the weak-measurement technique to study atom-vacuum interactions

TL;DR

This paper demonstrates how quantum weak measurement techniques can amplify and observe the subtle interactions between free atoms and the vacuum field inside a cavity, revealing new insights into atom-vacuum dynamics.

Contribution

It applies weak measurement to study atom-vacuum interactions, highlighting the amplification of weak signals and the role of postselection in revealing atom-field coupling effects.

Findings

Weak atom-vacuum interactions can produce large external motion changes.

Postselection enhances the detection of subtle atom-field effects.

The technique provides a new way to observe nonclassical phenomena.

Abstract

Quantum weak measurement has attracted much interest recently [J. Dressel et al., Rev. Mod. Phys. 86, 307 (2014)] because it could amplify some weak signals and provide a technique to observe nonclassical phenomena. Here, we apply this technique to study the interaction between the free atoms and the vacuum in a cavity. Due to the gradient field in the vacuum cavity, the external orbital motions and the internal electronic states of atoms can be weakly coupled via the atom-field electric-dipole interaction. We show that, within the properly postselected internal states, the weak atom-vacuum interaction could generate a large change to the external motions of atoms due to the postselection-induced weak values.