Quantum Lubricity

TL;DR

This paper investigates how quantum effects influence sliding friction, revealing that quantum tunneling can significantly reduce friction in systems with strong periodic potentials, leading to a phenomenon called quantum lubricity.

Contribution

It introduces a quantum Prandtl-Tomlinson model showing that quantum tunneling can dominate frictional behavior, especially in strong periodic potentials, a novel insight into quantum friction mechanisms.

Findings

Quantum tunneling enables particles to bypass barriers, reducing friction.

Strong periodic potentials enhance quantum effects, contrary to classical expectations.

Quantum lubricity arises from resonant tunneling, decreasing energy dissipation.

Abstract

The quantum motion of nuclei, generally ignored in sliding friction, can become important for an atom, ion, or light molecule sliding in an optical lattice. The density-matrix-calculated evolution of a quantum Prandtl-Tomlinson model, describing the frictional dragging by an external force of a quantum particle, shows that classical predictions can be very wrong. The strongest quantum effect occurs not for weak, but for strong periodic potentials, where barriers are high but energy levels in each well are discrete, and resonant tunnelling to excited states in the nearest well can preempt classical stick-slip with great efficiency. The resulting permeation of otherwise impassable barriers is predicted to cause quantum lubricity