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TT: Fachverband Tiefe Temperaturen

TT 5: Correlated Electrons: (General) Theory 1

TT 5.1: Vortrag

Montag, 20. März 2017, 09:30–09:45, HSZ 304

Parquet decomposition calculations of the electronic self-energy — Olle Gunnarsson¹, Thomas Schäfer², James LeBlanc³, Jaime Merino⁴, Giorgio Sangiovanni⁵, Georg Rohringer⁶, and •Alessandro Toschi² — ¹Max-Planck-Institut für Festkörperforschung, Stuttgart (Germany) — ²IFP, Technische Universität Wien (Austria) — ³Memorial University of Newfoundland, St. John’s (Canada) — ⁴Universidad Autónoma de Madrid (Spain) — ⁵University of Würzburg (Germany) — ⁶Russian Quantum Center, Moskow (Russia)

The parquet decomposition of the self-energy into classes of diagrams, those associated with specific scattering processes, can be exploited for different scopes. In our work[1], the parquet decomposition is used to unravel the underlying physics of non-perturbative numerical calculations. By applying DMFT and its cluster extensions to the Hubbard model, our calculations show that the self-energies in the underdoped regime are dominated by spin-scattering processes, consistent with the conclusions of the fluctuation diagnostics approach[2]. We find, however, that even for moderate couplings, well before the Mott transition, singularities appear in different terms of the decomposition, with the notable exception of the predominant spin-channel. We clarify how these singularities, which partly limit the utility of parquet-based algorithms, are never found in the fluctuation diagnostics procedure.

[1] O. Gunnarsson et al., Phys. Rev. B 93, 245102 (2016)

[2] O. Gunnarsson et al., Phys. Rev. Lett. 114, 236402 (2015)