Computational Quantum Many-Body Physics

By computational many-body techniques, our group studies the rich physics of strongly interacting quantum matter both in thermodynamic equilibrium, especially at low temperatures, as well as far from equilibrium.

Our research includes the dynamics of out of equilibrium quantum many-body systems and their thermalization process, as well as situations where statistical mechanics fails and new dynamical phases of matter emerge, for example due to strong disorder in the case of many-body localization. We are further interested in the physics of periodically driven many-body systems and also study open many-body systems undergoing nonunitary dynamics. A particularly interesting and universal aspect in generic many-body systems is the dynamics of quantum information, which can be quantified either by entanglement measures or out-of-time-order correlators, revealing how quantum information spreads through the system, which is related to thermalization and quantum chaos.

Quantum many-body systems are generically difficult to study due to the exponential number of degrees of freedom in terms of the number of particles, requiring high performance algorithms to access the universal physics. We use massively parallel exact diagonalization and exact time evolution techniques as well as tensor network methods and quantum Monte Carlo algorithms to tackle this challenging problem. We also explore how to exploit the massive potential of quantum computers for the digital quantum simulation of many-body physics.