Title: "Sign of the Times: Sign Problems in Modern Physics"
Abstract: Quantum mechanics has allowed tremendous progress in the theoretical understanding of our universe. One key to this, computational Monte Carlo techniques, have succeeded for strongly-correlated materials and lattice QCD. Alas, sign problems----when a sampling distribution fails to be a well defined probability-- stymie these methods in fermionic systems, finite density, and real-time quantum evolution. In this talk, I discuss the origin of sign problems and the recent developments in complexification and quantum computing that are helping to address them.