# Demonstration of the asymmetric lateral Casimir force between corrugated surfaces in the nonadditive regime

## TL;DR

This paper experimentally measures the asymmetric lateral Casimir force between corrugated surfaces, confirming theoretical predictions and highlighting deviations from approximate models, with implications for nanotechnology applications.

## Contribution

It demonstrates the asymmetric lateral Casimir force in the nonadditive regime and compares exact theory with approximations, including real material effects.

## Key findings

- Asymmetry in phase dependence of the lateral Casimir force observed.
- Excellent agreement between experimental data and exact theoretical calculations.
- Deviations from proximity force approximation quantified.

## Abstract

The measurement of the lateral Casimir force between two aligned sinusoidally corrugated Au-coated surfaces has been performed in the nonadditive regime. The use of deeper corrugations also allowed to demonstrate an asymmetry in the phase dependences of the lateral Casimir force, as predicted earlier. The measurement data are found to be in excellent agreement with the exact theoretical results computed at T=300 K including effect of real material properties. The deviations between the exact theory and the proximity force approximation are quantified. The obtained results are topical for applications in nanomachines.