Regensburg 2022 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 33: Nonequilibrium Quantum Many-Body Systems (joint session TT/DY)

TT 33.12: Talk

Thursday, September 8, 2022, 18:00–18:15, H22

Non-equilibrium optical conductivity for striped states: A time-dependent Gutzwiller analysis for the single-band Hubbard model — •Christian Martens and Götz Seibold — BTU Cottbus-Senftenberg, Institute of Physics, 03046 Cottbus, Germany

In recent years pump-probe experiments have turned out as a powerful tool to investigate the dynamics of correlated materials, e.g. transition metals or heavy fermion systems. In these experiments the system is prepared in a non-equilibrium state by a strong laser pulse, where the relaxation is afterwards examined by standard optical techniques. This method has also been applied to stripe ordered nickelates and cuprate superconductors where it allows to study the coupled order-parameter dynamics of charge- and spin-density waves and superconductivity.

Here we use the time-dependent Gutzwiller approximation for the single-band Hubbard model to analyse the non-equilibrium dynamics for stripe ground states of different symmetry. In particular we are interested in the interplay between spin and charge dynamics which is analysed by quenching the system in the charge or spin sector. This allows us to investigate the coupled relaxation dynamics as a function of the inserted energy. In contrast to the Hartree-Fock + random-phase-approximation the optical conductivity shows high-energy double occupancy fluctuations in addition to the low-energy collective mode. In the out-of equilibrium regime we find a softening of both modes depending on the inserted energy. Moreover the double occupancy exitation broadens into a continuum.