Energy spread and current-current correlation in quantum systems
  We consider energy (heat) transport in quantum systems, and establish a relationship between energy spread and energy current-current correlation function. The energy current-current correlation is related to thermal conductivity by the Green-Kubo formula, and thus this relationship allows us to study conductivity directly from the energy spread process. As an example, we investigate a spinless fermion model; the numerical results confirm the relationship. 
Yonghong Yan, Feng Jiang, and Hui Zhao
cond-mat.stat-mech cond-mat.mes-hall