Charge ratchet from spin flip: space-time symmetry paradox

TL;DR

This paper reveals a novel charge ratchet effect in symmetric systems driven by electric and magnetic fields, arising from quantum dissipation and spin flips due to spin-orbit interactions, challenging traditional symmetry-based explanations.

Contribution

It demonstrates that charge ratchet effects can occur without spatial or temporal asymmetry, due to the interplay of dissipation and spin-orbit induced spin flips.

Findings

Charge ratchet effect appears in symmetric potentials and driving fields.

Quantum dissipation combined with spin flips enables the effect.

Contradicts the traditional symmetry-breaking paradigm.

Abstract

Traditionally the charge ratchet effect is considered as a consequence of either the spatial symmetry breaking engineered by asymmetric periodic potentials, or time asymmetry of the driving fields. Here we demonstrate that electrically and magnetically driven quantum dissipative systems with spin-orbit interactions represent an exception from this standard idea. In contrast to the so far well established belief, a charge ratchet effect appears when both the periodic potential and driving are symmetric. We show that the source of this paradoxical charge ratchet mechanism is the coexistence of quantum dissipation with the spin flip processes induced by spin-orbit interactions.