Bold-line Monte Carlo and the nonequilibrium physics of strongly correlated many-body systems

This talk summarizes real time bold-line diagrammatic Monte-Carlo approaches to quantum impurity models, which make significant headway against the sign problem by summing over corrections to self-consistent diagrammatic expansions rather than a bare diagrammatic series. When the bold-line method is combined with reduced dynamics techniques\footnote{Guy Cohen, Eli Y. Wilner, and Eran Rabani. New Journal of Physics 15, 073018 (2013).} both local single-time properties\footnote{Guy Cohen, Emanuel Gull, David R. Reichman, Andrew J. Millis, and Eran Rabani. Physical Review B 87, 195108 (2013).} and two time correlators such as Green functions\footnote{Guy Cohen, David R. Reichman, Andrew J. Millis, and Emanuel Gull. Physical Review B 89, 115139 (2014).} can be computed at very long timescales, enabling studies of nonequilibrium steady state behavior of quantum impurity models\footnote{Guy Cohen, Emanuel Gull, David R. Reichman, and Andrew J. Millis. Physical Review Letters 112, 146802 (2014).} and creating new solvers for nonequilibrium dynamical mean field theory.