Converting heat into directed transport on a tilted lattice

TL;DR

This paper introduces a quantum engine where spins coupled to baths transfer energy and entropy to move a particle on a tilted lattice, demonstrating controlled directed transport driven by thermal interactions.

Contribution

It presents a novel self-contained quantum engine model using spins and a tilted lattice, showing energy transfer and directed motion even with minimal components.

Findings

Particle moves upward at constant speed driven by spins.

Velocity increases when tilt resonates with spin energy.

Spins exhibit periodic polarization cycles influenced by lattice tilt.

Abstract

We present a self-contained engine, which is made of one or more two-level systems, each of which is coupled to a single bath, as well as to a common load composed of a particle on a tilted lattice. We show that the energy and the entropy absorbed by the spins are transferred to the particle thus setting it into upward motion at an average constant speed, even when driven by a single spin connected to a single bath. When considering an ensemble of different spins, the velocity of the particle is larger when the tilt is on resonance with any of the spins' energy splitting. Interestingly, we find regimes where the spins' polarization enters periodic cycles with the oscillation period being determined by the tilt of the lattice.