Thermal Casimir drag in fluctuating classical fields

TL;DR

This paper investigates how a moving object that suppresses thermal fluctuations in a classical field experiences a drag force, with the force's characteristics depending on the field's dynamics and object properties.

Contribution

It introduces a model for thermal Casimir drag on objects in fluctuating fields, highlighting the dependence on object stiffness and field dynamics, and simplifies the friction coefficient in certain cases.

Findings

Drag force depends on field dynamics and object properties.

Short distance fluctuations dominate the linear friction coefficient.

Applicable to proteins on flexible structures like polymers and membranes.

Abstract

A uniformly moving inclusion which locally suppresses the fluctuations of a classical thermally excited field is shown to experience a drag force which depends on the dynamics of the field. It is shown that in a number of cases the linear friction coefficient is dominated by short distance fluctuations and takes a very simple form. Examples where this drag can occur are for stiff objects, such as proteins, nonspecifically bound to more flexible ones such as polymers and membranes.