Precision measurement of the Casimir-Lifshitz force in a fluid

TL;DR

This study presents the first high-precision measurements of the Casimir-Lifshitz force between two metals immersed in a fluid, confirming theoretical predictions and revealing a smaller attractive force than in vacuum conditions.

Contribution

It provides experimental validation of the Casimir-Lifshitz theory for metal interactions in a fluid, expanding understanding beyond vacuum and air environments.

Findings

Measured force is approximately 80% smaller than ideal vacuum predictions.

Force remains attractive in fluid, consistent with Lifshitz's theory.

Results support the robustness of the generalized Casimir-Lifshitz theory in fluid media.

Abstract

The Casimir force, which results from the confinement of the quantum mechanical zero-point fluctuations of the electromagnetic fields, has received significant attention in recent years for its effect on micro- and nano-scale mechanical systems. With few exceptions, experimental observations have been limited to conductive bodies interacting separated by vacuum or air. However, interesting phenomena including repulsive forces are expected to exist in certain circumstances between metals and dielectrics when the intervening medium is not vacuum. In order to better understand the effect of the Casimir force in such situations and to test the robustness of the generalized Casimir-Lifshitz theory, we have performed the first precision measurements of the Casimir force between two metals immersed in a fluid. For this situation, the measured force is attractive and is approximately 80% smaller than the force predicted by Casimir for ideal metals in vacuum. We present experimental results and find them to be consistent with Lifshitz's theory.