Quantum systems out of equilibrium
Research objectives
Recent time-resolved measurements have given a new insight into the nonequilibrium dynamics of realistic bulk materials and nanosystems as well as the systems of ultracold atoms. In contrast to the spectacular developments in the experimental methods, theoretical description of the nonequilibrium dynamics remains a challenging task with very few exactly-solvable problems. Two general problems addressed in our studies concern:
(i) Driving, relaxation and reduced dynamics under far from equilibrium conditions
(ii) Particle and energy currents in correlated quantum systems out of equilibrium. We try to understand the physical mechanisms which determine the boundaries of the linear-response regime for particle and energy currents, find the time-scale for relaxation from far-from-equilibrium states and establish conditions for thermalization of isolated systems. We also try to determined the relation between particle and energy currents under nonequilibrium conditions.
Research methodology
When studying the real--time response of solids and nanosystems we mostly apply microcanonical Lanczos method(MCLM) combined with the Lanczos propagation method. It can be used for much larger systems than ED carried out in the full Hilbert space. The key advantages of MCLM over other methods consists in its flexibility.
Research impact and main publications
The nonequilibrium real--time response of quantum systems has recently become important for various branched of physics: condensed--matter and nanophyics as well as for physics of ultracold atoms. The main objectives discussed are important for basic research and possibly also for the future applications.
1. Stefano Dal Conte, Lev Vidmar, Denis Golež, Marcin Mierzejewski, et al, Snapshots of the retarded interaction of charge carriers with ultrafast fluctuations in cuprates, accepted for Nature Physics
2. M. Mierzejewski, P. Prelovsek and T. Prosen, Breakdown of the generalized Gibbs ensemble for current-generating quenches, Phys. Rev. Lett. 113, 020602 (2014).
3. M. Mierzejewski, T. Prosen, D. Crivelli and P. Prelovsek, Eigenvalue statistics of reduced density matrix during driving and relaxation, Phys. Rev. Lett. 110, 200602 (2013).
4. J. Bonca, M. Mierzejewski, L. Vidmar, Nonequilibrium propagation and decay of a bound pair in driven t-J models, Phys. Rev. Lett 109, 156404 (2012).
5. M. Mierzejewski, J. Bonca, and P. Prelovsek, Integrable Mott insulators driven by finite electric field, Phys. Rev. Lett. 107, 126601 (2011).
6. M. Mierzejewski, L. Vidmar, J. Bonca, and P. Prelovsek, Nonequilibrium quantum dynamics of a charge carrier doped into Mott insulator, Phys. Rev. Lett. 106, 196401 (2011)
7. M. Mierzejewski and P. Prelovšek, Nonlinear Current Response of an Isolated System of Interacting Fermions, Phys. Rev. Lett. 105, 186405 (2010)