TY  - JOUR
AU  - Schäfer, Thomas
AU  - Wentzell, Nils
AU  - Šimkovic, Fedor
AU  - He, Yuan-Yao
AU  - Hille, Cornelia
AU  - Klett, Marcel
AU  - Eckhardt, Christian J.
AU  - Arzhang, Behnam
AU  - Harkov, Viktor
AU  - Le Régent, François-Marie
AU  - Kirsch, Alfred
AU  - Wang, Yan
AU  - Kim, Aaram J.
AU  - Kozik, Evgeny
AU  - Stepanov, Evgeny A.
AU  - Kauch, Anna
AU  - Andergassen, Sabine
AU  - Hansmann, Philipp
AU  - Rohe, Daniel
AU  - Vilk, Yuri M.
AU  - LeBlanc, James P. F.
AU  - Zhang, Shiwei
AU  - Tremblay, A.-M. S.
AU  - Ferrero, Michel
AU  - Parcollet, Olivier
AU  - Georges, Antoine
TI  - Tracking the Footprints of Spin Fluctuations: A MultiMethod, MultiMessenger Study of the Two-Dimensional Hubbard Model
JO  - Physical review / X
VL  - 11
IS  - 1
SN  - 2160-3308
CY  - College Park, Md.
PB  - APS
M1  - FZJ-2021-01490
SP  - 011058
PY  - 2021
AB  - The Hubbard model represents the fundamental model for interacting quantum systems and electronic correlations. Using the two-dimensional half-filled Hubbard model at weak coupling as a testing ground, we perform a comparative study of a comprehensive set of state-of-the-art quantum many-body methods. Upon cooling into its insulating antiferromagnetic ground state, the model hosts a rich sequence of distinct physical regimes with crossovers between a high-temperature incoherent regime, an intermediate-temperature metallic regime, and a low-temperature insulating regime with a pseudogap created by antiferromagnetic fluctuations. We assess the ability of each method to properly address these physical regimes and crossovers through the computation of several observables probing both quasiparticle properties and magnetic correlations, with two numerically exact methods (diagrammatic and determinantal quantum Monte Carlo methods) serving as a benchmark. By combining computational results and analytical insights, we elucidate the nature and role of spin fluctuations in each of these regimes. Based on this analysis, we explain how quasiparticles can coexist with increasingly long-range antiferromagnetic correlations and why dynamical mean-field theory is found to provide a remarkably accurate approximation of local quantities in the metallic regime. We also critically discuss whether imaginary-time methods are able to capture the non-Fermi-liquid singularities of this fully nested system.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000631686900001
DO  - DOI:10.1103/PhysRevX.11.011058
UR  - https://juser.fz-juelich.de/record/891405
ER  -