Decoherence in current induced forces: Application to adiabatic quantum motors

TL;DR

This paper develops a theory incorporating decoherence into current induced forces, revealing its impact on quantum motor efficiency and operation, with applications to adiabatic quantum motors and insights into environmental effects on nano-mechanical devices.

Contribution

It introduces a reformulated Büttiker probe model to include dephasing in current induced forces and analyzes its effects on quantum motor performance.

Findings

Decoherence influences current induced forces, friction, and noise in quantum systems.

Total work by current induced forces equals pumped charge times voltage, even with decoherence.

Decoherence can trigger operation of quantum motors inspired by classical pumps.

Abstract

Current induced forces are not only related with the discrete nature of electrons but also with its quantum character. It is natural then to wonder about the effect of decoherence. Here, we develop the theory of current induced forces including dephasing processes and we apply it to study adiabatic quantum motors (AQMs). The theory is based on B\"uttiker's fictitious probe model which here is reformulated for this particular case. We prove that it accomplishes fluctuation-dissipation theorem. We also show that, in spite of decoherence, the total work performed by the current induced forces remains equal to the pumped charge per cycle times the voltage. We find that decoherence affects not only the current induced forces of the system but also its intrinsic friction and noise, modifying in a non trivial way the efficiency of AQMs. We apply the theory to study an AQM inspired by a classical peristaltic pump where we surprisingly find that decoherence can play a crucial role by triggering its operation. Our results can help to understand how environmentally induced dephasing affects the quantum behavior of nano-mechanical devices.