A new route towards the dynamical mean field theory of strongly correlated nonequilibrium systems based on hierarchical master equation methods

• Applicant: Dr. Rainer Härtle
• Subject Area: Theoretical Condensed Matter Physics
• Term: from 2015 to 2017
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 261975638

Dynamical mean field theory is one of the most successful approaches to describe strongly correlated materials. This success is largely based on the description of equilibrium properties, but much less is known about these materials if they are driven away from equilibrium. The problem is the description of collective phenomena, which often require an exact treatment of the underlying many-body problem. To date and in particular for nonequilibrium situations, this can be achieved only by a limited number of approaches. It is therefore proposed to develop and employ hierarchical quantum master equation techniques to solve the impurity problem of the dynamical mean-field ansatz. The resulting methodology can be expected to overcome some of the major limitations of previous approaches. This includes, for example, the description of any type of (local) interactions, multiorbital effects and the time scales that can be simulated. The latter is particularly important for strongly correlated systems because the corresponding nonequilibrium dynamics can span several orders of magnitude. Thus, for example, states or phases may be studied that cannot exist in equilibrium situations. Such states are currently accessed in a number of experiments, because they may be very interesting, inter alia, for a number of technological applications.

• DFG Programme: Research Grants
• Participating Persons: Professor Dr. Stefan Kehrein; Professor Dr. Thomas Pruschke (†)