Some of the most powerful approaches for the description of strongly correlated materials involves the reduction of the problem to that of a small system interacting with a fluctuating environment, namely a quantum impurity problem. Dynamical mean-field theory (DMFT) provides the most prominent example of this paradigm. Within DMFT, the reduction of the problem of the electronic structure of a strongly correlated solid to that of a quantum impurity problem does not complete the program because the real-time 1-particle Green function of the impurity problem is still required. In this talk I will describe a powerful new algorithm for the solution of real-time quantum dynamics that is exact, stable for long times and capable of treating all relevant regimes of quantum impurity models of the type that emerge in DMFT and in more general settings. The approach, which we call the "inchworm algorithm," reduces the exponential scaling of the problem to quadratic scaling, and may be useful in other areas of strongly correlated quantum problems.<br/><br/>

Taming the dynamical sign problem in the real time evolution of quantum impurity problems

251st National Meeting (2016)

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