Dynamical Properties of Strongly Correlated Fermionic Systems

Barnali Chakrabarti, N. D. Chavda, Andrea Trombettoni +1 more

We investigate the transport properties in out-of-equilibrium dynamics of strongly correlated dipolar fermions initially localized in one-dimensional inhomogeneous optical lattice. The dynamics is studied by experimentally measurable dynamical variables such as one-body density, pair-correlation function and size of the expanding cloud. In the noninteracting limit, we trace the usual fingerprints of ballistic expansion in the short time dynamics. However, dynamics is strongly affected by system size due to Pauli principle. The dynamics also exhibits significant dependence on the sign of the interactions. We observe that strong repulsive dipolar interaction gives rise to many-body features in the dynamics, while strong attractive dipolar interaction leads to stabilized cluster states. Intermediate dipolar interaction are found to hinder expansion of correlations, while very strong dipolar interaction favors expansion of the cloud. Our work show the effect of dipolar interaction in the transport properties of interacting fermions, that can be studied in on-going experiments with ultracold dipolar fermions.

W. Cassing, A. Pfitzner

An Bao, Yao‐Hua Chen, Heng-Fu Lin +2 more

In this article, we review our recent work on quantum phase transition in two-dimensional strongly correlated fermion systems. We discuss the metal–insulator transition properties of these systems by calculating the density of states, double occupancy, and Fermi surface evolution using a combination of the cellular dynamical mean-field theory (CDMFT) and the continuous-time quantum Monte Carlo algorithm. Furthermore, we explore the magnetic properties of each state by defining magnetic order parameters. Rich phase diagrams with many intriguing quantum states, including antiferromagnetic metal, paramagnetic metal, Kondo metal, and ferromagnetic insulator, were found for the two-dimensional lattices with strongly correlated fermions. We believe that our results would lead to a better understanding of the properties of real materials.

Yukinori Ota, 太田 幸則

Ettore Vitali, Hao Shi, Mingpu Qin +1 more

Quantum Monte Carlo simulations provide a powerful tool to compute static properties of quantum many-particles models and realistic systems. A vast array of ground-state energies and properties defined by equal-time correlation functions can be computed with high accuracy. On the other hand, the extensions needed to study time-displaced correlation functions, which provide access to excited states, have been challenging, especially for fermionic strongly correlated systems. The authors present a methodology that allows a high-accuracy calculation of the dynamical Green functions of many-fermions systems in the framework of the auxiliary-field quantum Monte Carlo method. They extract the the charge gap of the repulsive two-dimensional Hubbard model at half-filling as a function of the interaction strength and propose strategies for applying their methodology to more realistic systems.

José M. Arias, María Isabel Gallardo, Manuel Lozano