Efficient Quantum Ratchet

TL;DR

This paper demonstrates that desynchronizing potentials in a quantum ratchet enhances quantum resonances, leading to more efficient directed currents and deeper insights into symmetry breaking in quantum dynamics.

Contribution

It introduces a novel method of desynchronizing kicked potentials to stimulate new quantum resonances and improve directed transport efficiency.

Findings

Missed resonances at κ=1.0π and κ=3.0π induce larger currents.

Semiclassical analysis confirms the results are exact.

Enhanced quantum resonances lead to more efficient directed transport.

Abstract

Quantum resonance is one of the main characteristics of the quantum kicked rotor, which has been used to induce accelerated ratchet current of the particles with a generalized asymmetry potential. Here we show that by desynchronizing the kicked potentials of the flashing ratchet [Phys. Rev. Lett. 94, 110603 (2005)], new quantum resonances are stimulated to conduct directed currents more efficiently. Most distinctly, the missed resonances $\kappa=1.0\pi$ and $\kappa=3.0\pi$ are created out to induce even larger currents. At the same time, with the help of semiclassical analysis, we prove that our result is exact rather than phenomenon induced by errors of the numerical simulation. Our discovery may be used to realize directed transport efficiently, and may also lead to a deeper understanding of symmetry breaking for the dynamical evolution.