Equivalence of transport coefficients in bath-induced and dynamical scenarios

TL;DR

This paper compares bath-induced and dynamical scenarios for excitation transport in a chain, showing diffusive and ballistic regimes with consistent conductivity and diffusion coefficients across methods.

Contribution

It demonstrates the equivalence of transport coefficients in bath-induced and dynamical models for excitation transport in a chain.

Findings

Diffusive transport occurs in a specific parameter range.

Conductivity is independent of bath coupling strength in the diffusive regime.

Ballistic behavior aligns with results from alternative approaches.

Abstract

We investigate the transport of a single excitation through a chain of weakly coupled subunits. At both ends the chain is exposed to baths which are incorporated by means of a master equation in Lindblad form. This master equation is solved by the use of stochastic unraveling in order to obtain excitation profile and current in the steady state. Completely diffusive transport is found for a range of model parameters, whereas signatures of ballistic behavior are observed outside this range. In the diffusive regime the conductivity is rather independent from the strength of the bath coupling and quantitatively agrees with the diffusion coefficient which has been derived from an investigation of the same model without baths. Also the ballistic behavior in the non-diffusive regime is in accord with results from this alternative approach.