# Dresden 2020 – wissenschaftliches Programm

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# TT: Fachverband Tiefe Temperaturen

## TT 62: Correlated Electrons: Method Development 2

### TT 62.1: Vortrag

### Donnerstag, 19. März 2020, 15:00–15:15, HSZ 204

π-tons − Characteristics of vertex corrections to the optical conductivity in strongly correlated metals. — •Paul Worm, Clemens Watzenböck, Anna Kauch, and Karsten Held — Institute of Solid State Physics, TU Wien, 1040 Vienna, Austria

The interaction of a solid with an electromagnetic field, or from a quantum point of view with photons, gives rise to new quasi-particles coined polaritons. For semi-conductors the exciton is the generic polariton, the characteristics of which are rather well understood. In strongly correlated systems the dominant polariton was shown to be different, namely a recent study using the parquet equations [1], which are not biased in favor or against certain channels or physics, observed in Hubbard-like systems new polaritons: π-tons. These π-tons manifest themselves in vertex corrections to the optical conductivity that are dominated by the contributions in the particle-hole transversal channel. They consist of two particle-hole pairs glued together by anitferromagnetic or charge density wave fluctuations.

In order to investigate the π-ton contributions in more detail and without the necessity of a cumbersome numeric analytic continuation we use a simplified real frequency formalism, which grants us complete control over the diagrams included. We reproduce the core features of the vertex corrections with simplified ladder diagrams in the particle-hole transversal channel [1]. This confirms these ladder diagrams are indeed the dominant vertex contributions.

[1] A.Kauch et al., arXiv:1902.09342