Universal Casimir interaction between two dielectric spheres in salted water

TL;DR

This paper investigates the universal Casimir interaction between dielectric spheres in salted water, highlighting its independence from dielectric properties and dependence on geometry, driven by low-frequency thermal fluctuations.

Contribution

It reveals the universal nature of Casimir forces in salted solutions, emphasizing conformal invariance and geometric dependence at large distances.

Findings

Interaction dominated by low-frequency thermal fluctuations

Universality independent of dielectric functions

Dependence on geometric dimensions

Abstract

We study the Casimir interaction between two dielectric spheres immersed in a salted solution at distances larger than the Debye screening length. The long distance behavior is dominated by the non-screened interaction due to low-frequency transverse magnetic thermal fluctuations. It shows universality properties in its dependence on geometric dimensions and independence of dielectric functions of the particles, with these properties related to approximate conformal invariance.