Characterizing the Non-equilibrium Dynamics of Field-Driven Correlated Quantum Systems

• Main Authors: Herbert F. Fotso, James K. Freericks
• Format: Article
• Language: English
• Published: Frontiers Media S.A. 2020-08-01
• Series: Frontiers in Physics
• Subjects: non-equilibrium; dynamics; correlated systems; field-driven; Keldysh; thermalization
• Online Access: https://www.frontiersin.org/article/10.3389/fphy.2020.00324/full

Recent experimental advances in ultrafast phenomena have triggered renewed interest in the dynamics of correlated quantum systems away from equilibrium. We review non-equilibrium dynamical mean-field theory studies of both the transient and the steady states of a DC field-driven correlated quantum system. In particular, we focus on the non-equilibrium behavior and how it relates to the fluctuation-dissipation theorem. The fluctuation-dissipation theorem emerges as an indicator for how the system thermalizes and for how it reaches a steady state. When the system thermalizes in an infinite temperature steady state it can pass through a succession of quasi-thermal states that approximately obey the fluctuation-dissipation theorem. We also discuss the Wigner distribution and what its evolution tells us about the non-equilibrium many-body problem.