Berlin 2018 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe

TT: Fachverband Tiefe Temperaturen

TT 94: Correlated Electrons: Other Theoretical Topics

TT 94.9: Vortrag

Donnerstag, 15. März 2018, 17:30–17:45, H 3010

Single-particle properties of the 2D Hubbard model within a four-pole approximation — •Andrea Di Ciolo and Adolfo Avella — Dipartimento di Fisica "E. R. Caianiello", Università degli Studi di Salerno, I-84084 Fisciano (SA), Italy

We present a solution of the 2D Hubbard model in the framework of the Composite Operator Method (COM) [1-3] within a four-pole approximation (4p). First, we characterize the 2-site exact solution and identify the crucial role played by spin fluctuations. Then, we adopt a basis of fields given by the two Hubbard operators plus two fields describing the electronic transitions dressed by the nearest-neighbor spin fluctuations. As well as this approximate solution is in remarkable agreement with the 2-site exact one, the corresponding 2D solution performs very well once compared to advanced (semi-)numerical methods, being by far less computational-resource demanding. Moreover, this solution, featuring a well-developed momentum selectivity of the spectral properties, opens up the possibility to directly address the underdoped-cuprate puzzle. Therefore, we adopt this 4p approximation to study the single-particle properties of the 2D model in the strong coupling regime (intermediate-large interaction and small-intermediate doping), where the effects of spin-fluctuations, accurately treated in our approach, are more relevant and induce anomalous features in all analyzed properties.
F. Mancini, and A. Avella, Adv. Phys. 53, 537 (2004).
A. Avella, Eur. Phys. J. B, 87, 45 (2014).
A. Avella, Adv. Cond. Matt. Phys. 2014, 515698 (2014).