scholarly journals Exploring nonequilibrium phases of photo-doped Mott insulators with generalized Gibbs ensembles

2022 ◽  
Vol 5 (1) ◽  
Author(s):  
Yuta Murakami ◽  
Shintaro Takayoshi ◽  
Tatsuya Kaneko ◽  
Zhiyuan Sun ◽  
Denis Golež ◽  
...  
Keyword(s):  
Density Wave ◽  
Strongly Correlated Systems ◽  
Mott Insulators ◽  
Time Behavior ◽  
Strongly Correlated ◽  
Systematic Analysis ◽  
Correlated Systems ◽  
Long Time ◽  
Nonequilibrium States ◽  
The One

AbstractMany experiments show that strong excitations of correlated quantum materials can cause non-thermal phases without equilibrium analogues. Understanding the origin and properties of these nonequilibrium states has been challenging due to the limitations of theoretical methods for nonequilibrium strongly correlated systems. In this work, we introduce a generalized Gibbs ensemble description that enables a systematic analysis of the long-time behavior of photo-doped states in Mott insulators based on equilibrium methods. We demonstrate the power of the method by mapping out the nonequilibrium phase diagram of the one-dimensional extended Hubbard model, which features η-pairing and charge density wave phases in a wide photo-doping range. We furthermore clarify that the peculiar kinematics of photo-doped carriers, and the interaction between them, play an essential role in the formation of these non-thermal phases. Our results establish a new path for the systematic analysis of nonequilibrium strongly correlated systems.

scholarly journals Regularized Second-Order Correlation Methods for Extended Systems

2021 ◽  
Author(s):  
Elisabeth Keller ◽  
Theodoros Tsatsoulis ◽  
Karsten Reuter ◽  
Johannes T. Margraf
Keyword(s):  
Computational Cost ◽  
Cost Effective ◽  
Strongly Correlated Systems ◽  
Second Order ◽  
Strongly Correlated ◽  
Many Body ◽  
Correlated Systems ◽  
Extended Systems ◽  
Moller Plesset ◽  
The One

While many-body wavefunction theory has long been established as a powerful framework for highly accurate molecular quantum chemistry, these methods have only fairly recently been applied to extended systems in a significant scale. This is due to the high computational cost of such calculations, requiring efficient implementations and ample computing resources. To further aggravate this, second-order Møller-Plesset perturbation theory (MP2) (the most cost effective wavefuntion method) is known to diverge or fail for some prototypical condensed matter systems like the homogeneous electron gas (HEG). In this paper, we explore how the issues of MP2 for metallic and strongly correlated systems can be ameliorated through regularization. To this end, two regularized second-order methods (including a new, size-extensive Brillioun-Wigner approach) are applied to the HEG, the one-dimensional Hubbard model and the graphene-water interaction energy. We find that regularization consistently leads to improvements over the MP2 baseline and that different regularizers are appropriate for metallic and strongly correlated systems, respectively.

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