# Dresden 2020 – wissenschaftliches Programm

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# TT: Fachverband Tiefe Temperaturen

## TT 62: Correlated Electrons: Method Development 2

### TT 62.5: Vortrag

### Donnerstag, 19. März 2020, 16:00–16:15, HSZ 204

Dual parquet scheme for the two-dimensional Hubbard model: modelling low-energy physics of high-T_{c} cuprates with high momentum resolution — Grigory Astretsov^{1,2}, •Georg Rohringer^{1,3}, and Alexey Rubtsov^{1,2} — ^{1}Russian Quantum Center — ^{2}Lomonosov Moscow State University — ^{3}University of Hamburg

We present a new method to treat the two-dimensional (2D) Hubbard model for parameter regimes which are relevant for the physics of the high-T_{c} superconducting cuprates. Our approach consists in the following three-step procedure: (i) High energy correlations are treated exactly by dynamical mean field theory (DMFT). From the DMFT solution we (ii) construct an effective low-energy model which depends only on the lowest Matsubara frequencies. We (iii) apply the two-particle self-consistent parquet formalism which takes into account the competition between different low-energy bosonic modes. In this way, we were able to map out the phase diagram of the 2D Hubbard model as a function of temperature and doping. Consistently with the experimental evidence for hole-doped cuprates and previous dynamical cluster approximation calculations, we find an antiferromagnetic region at low doping and a superconducting dome at higher doping. Our results also support the role of the van Hove singularity as an important ingredient for the high value of T_{c} at optimal doping. At small doping, the destruction of antiferromagnetism is accompanied by an increase of charge fluctuations supporting the scenario of a phase separated state driven by quantum critical fluctuations.