Interacting systems far from equilibrium

We are interested in the interplay of correlation and scattering effects in the real-time domain and their manifestation in ultrafast spectroscopies. To this end we are employing the time-dependent nonequilibrium Green's function (td-NEGF) method to learn about dynamics in interacting systems.

The heart of the method is the solution of the Kadanoff-Baym equations for the Green's function on the L-shaped contour. This is numerically and computationally challenging; in our open-source software package NESSi we have implemented all of the "dirty work" - it is ready to use. Also check our publication on the package and the excellent text book by Stefanucci and van Leeuwen if you want to learn more.

With these powerful tools at hand, we address questions of scattering dynamics in different systems (Is there an interplay between band topolgy and scattering? Can as system thermalize or are there interesting nonthermal states? Can we extract microscopic interactions from the dynamics?). The method also provides a direct link to time-resolved spectroscopies. We are collaborating with a number of experimental groups on time-resolved photoemission spectroscopy to track nonequilibrium phenomena in quantum materials.

Relevant publications:

1. Dynamical signatures of symmetry protected topology following symmetry breaking
   J. A. Marks, M. Schüler, T. P. Devereaux
   Phys. Rev. Research 3, 023137 (2021)

2. Dynamically Induced Exceptional Phases in Quenched Interacting Semimetals
   C. Lehmann, M. Schüler, J. C. Budich
   Phys. Rev. Lett. 127, 106601 (2021)

3. Correlation-assisted quantized charge pumping
   J. A. Marks, M. Schüler, J. C. Budich, T. P. Devereaux
   Phys. Rev. B 103, 035112 (2021)

4. How Circular Dichroism in Time- and Angle-Resolved Photoemission Can Be Used to Spectroscopically Detect Transient Topological States in Graphene
   M. Schüler, U. De Giovannini, H. Hübener, A. Rubio, M. A. Sentef, T. P. Devereaux, P. Werner
   Phys. Rev. X 10, 041013 (2020)

5. NESSi: The Non-Equilibrium Systems Simulation package
   M. Schüler, D. Golež, Y. Murakami, N. Bittner, A. Herrmann, H. U. R. Strand, P. Werner, M. Eckstein
   Comp. Phys. Comm. 257, 107484 (2020)

6. Ultrafast nonequilibrium evolution of excitonic modes in semiconductors
   Y. Murakami, M. Schüler, S. Takayoshi, P. Werner
   Phys. Rev. B 101, 035203 (2020)

7. Quench dynamics and Hall response of interacting Chern insulators
   M. Schüler, J. C. Budich, P. Werner
   Phys. Rev. B 100, 041101 (2019)

8. Adiabatic Preparation of a Correlated Symmetry-Broken Initial State with the Generalized Kadanoff–Baym Ansatz
   R. Tuovinen, D. Golež, M. Schüler, P. Werner, M. Eckstein, M. A. Sentef
   Phys. Stat. Solid. B 256, 1800469 (2018)

9. Truncating the memory time in nonequilibrium DMFT calculations
   M. Schüler, M. Eckstein, P. Werner
   Phys. Rev. B 97, 245129 (2018)

10. Nonthermal switching of charge order: Dynamical slowing down and optimal control
    M. Schüler, Y. Murakami, P. Werner
    Phys. Rev. B 97, 155136 (2018)

11. Tracing the nonequilibrium topological state of Chern insulators
    M. Schüler, P. Werner
    Phys. Rev. B 96, 155122 (2017)