Quantum versus classical transport of energy in coupled two-level systems

TL;DR

This paper compares quantum and classical energy transport in coupled two-level systems, identifying thresholds where quantum coherence enhances efficiency and highlighting quantum invasiveness as a key resource.

Contribution

It introduces thresholds for quantum coherence to outperform classical transport and links invasiveness to quantum transport efficiency.

Findings

Quantum coherence improves transport efficiency above a certain threshold.

Invasiveness of quantum operations correlates with enhanced energy transport.

Quantum resources can surpass classical limits in energy transfer.

Abstract

We consider the problem of energy transport in a chain of coupled quantum systems with the goal of shedding light on how nonclassical resources can affect transport. We study the cases for which either coherent or incoherent energy hopping takes place in the chain. Here, incoherent energy hopping is referred to as the "classical" scenario in allusion to its fully diagonal dynamics in the basis formed by the eigenstates of the decoupled sites. We focus on the case of a linear chain of two-level sites and find a hopping rate threshold above which the coherent quantum case is more efficient than the incoherent counterpart. We then link the quantum hopping rate to the coherence global maximum, which allows us to state that there is a coherence threshold above which the quantum scenario is more efficient. Next, we consider the integrated coherence generated by the dynamics and show how it is related to what is known as the invasiveness of a quantum operation. Our results strongly suggest the significant role played by quantum invasiveness as a resource for quantum transport.