Charge and heat transport at the nanoscale: elementary models - involved methods

I will describe our research interests in the area of quantum dynamics and molecular conduction. I will present two seemingly simple models for charge and heat transfer in molecular junctions and discuss our efforts in developing and benchmarking appropriate simulation tools. The first model concerns charge transfer in a two-site electronic junction with electron-vibration interaction effects and energy dissipation to secondary phonons [1]. The second model, the so called nonequilibrium spin-boson model, allows us to study principles of quantum energy flow in anharmonic systems [2].

I will outline different methodologies that we have been advancing for calculating transport characteristics in these interacting models: An iterative influence functional path integral approach and perturbative tools, quantum master equation, the nonequilibrium Green's function approach. I will explain our efforts in developing these methods in a consistent manner, and exemplify nontrivial function, diode behavior, thermoelectric energy conversion, and negative differential thermal conductance.


[1] B. K. Agarwalla, J.-H. Jiang and D. Segal,
Full counting statistics of vibrationally-assisted electronic conduction: transport and fluctuations of the thermoelectric efficiency,
arXiv:1508.02475, Phys. Rev. B in press.

[2] N. Boudjada and D. Segal,
From dissipative dynamics to studies of heat transfer at the nanoscale: Analysis of the spin-boson model,
J. Phys. Chem. A, 118 (47), 11323-11336 (2014).