Short-time dynamics of correlated finite fermion systems - a Nonequilibrium Green functions approach

点击翻译按钮获取中文摘要

Nonequilibrium quantum dynamics of many-body and few-body systems remains one of the unresolved problems of theoretical physics. Recently this topic gained new interest due to novel applications and experiments in a broad range of fields ranging from ultracold atoms to condensed matter as well as to dense plasmas and atomic and molecular systems. Experimental progress giving time-resolved access to new observables well beyond average thermodynamic quantities of macroscopic systems poses a considerable challenge to theory. Accurate modeling of interacting quantum many-body systems far from equilibrium is very challenging due to the large number of independent variables and the breakdown of perturbative approaches that would allow to use ground state or equilibrium results as an input. Moreover, the simultaneous presence of multiple time scales governing nonequilibrium dynamics, the importance of correlations and finite size effects is challenging for the applicability of any given advanced method. The initial stage of excitation, collisional redistribution, and onset of relaxation is particularly difficult to describe adequately, requiring advanced methods of many-body theory. However, these methods are computationally expensive and, therefore, until now, have been restricted to short time scales or/and small system sizes. The present project aims to significantly relieve these restrictions, taking advantage of recent breakthroughs in the field of nonequilibrium Green functions. Aside from the development of theoretical methods the project will obtain new results for the short-time dynamics of graphene nanoribbon heterostructures exposed to short laser pulses that fully take into account electronic correlations.