Eur. Phys. J. B (2015) 88: 39
https://doi.org/10.1140/epjb/e2014-50797-4

Regular Article

Energy spread and current-current correlation in quantum systems

¹ Department of Physics, Shaoxing University, Shaoxing 312000, P.R. China
² School of Mathematics and Physics, Shanghai University of Electric Power, Shanghai 200090, P.R. China
³ Key Laboratory for Advanced Microstructure Materials of the Ministry of Education and Department of Physics, Tongji University, Shanghai 200092, P.R. China

^a e-mail: yhyan@fudan.edu.cn

Received: 14 November 2014
Published online: 4 February 2015

Abstract

We consider energy (heat) transport in quantum systems, and establish a relationship between energy spread and energy current-current correlation function within linear response theory. The energy current-current correlation is related to thermal conductivity by the Green-Kubo formula, and thus this relationship allows us to extract heat conductivity from the energy spread process. As an example, we investigate a spinless fermion model. At high temperatures, we find good agreement between numerical results and theory. At low temperatures and for finite systems, boundary terms however need to be taken into account due to the finite-size effect.