Quantum critical points and the sign problem

R Mondaini, S Tarat, RT Scalettar - Science, 2022 - science.org
The “sign problem”(SP) is a fundamental limitation to simulations of strongly correlated
matter. It is often argued that the SP is not intrinsic to the physics of particular Hamiltonians …

Universality and critical exponents of the fermion sign problem

R Mondaini, S Tarat, RT Scalettar - Physical Review B, 2023 - APS
Initial characterizations of the fermion sign problem focused on its evolution with spatial
lattice size L and inverse temperature β, emphasizing the implications of the exponential …

Bilayer Hubbard model: Analysis based on the fermionic sign problem

Y Mou, R Mondaini, RT Scalettar - Physical Review B, 2022 - APS
The bilayer Hubbard model describes the antiferromagnet to spin singlet transition and,
potentially, aspects of the physics of unconventional superconductors. Despite these …

Correlations in a band insulator

M Sentef, J Kuneš, P Werner, AP Kampf - Physical Review B—Condensed …, 2009 - APS
We study a model of a covalent band insulator with on-site Coulomb repulsion at half filling
using dynamical mean-field theory. Upon increasing the interaction strength the system …

Quotient symmetry protected topological phenomena

R Verresen, J Bibo, F Pollmann - arXiv preprint arXiv:2102.08967, 2021 - arxiv.org
Topological phenomena are commonly studied in phases of matter which are separated
from a trivial phase by an unavoidable quantum phase transition. This can be overly …

Doping a correlated band insulator: A new route to half-metallic behavior

A Garg, HR Krishnamurthy, M Randeria - Physical Review Letters, 2014 - APS
We demonstrate in a simple model the surprising result that turning on an on-site Coulomb
interaction U in a doped band insulator leads to the formation of a half-metallic state. In the …

Insulating behavior with spin and charge order in the ionic Hubbard model

K Byczuk, M Sekania, W Hofstetter, AP Kampf - Physical Review B …, 2009 - APS
Paramagnetic solutions of the ionic Hubbard model at half-filling in dimensions D> 2
indicate that the band and the Mott insulator phases are separated by a metallic phase. We …

Phase diagram of the half-filled ionic Hubbard model

S Bag, A Garg, HR Krishnamurthy - Physical Review B, 2015 - APS
We study the phase diagram of the ionic Hubbard model (IHM) at half filling on a Bethe
lattice of infinite connectivity using dynamical mean-field theory (DMFT), with two impurity …

Electric polarization in correlated insulators

R Nourafkan, G Kotliar - Physical Review B—Condensed Matter and Materials …, 2013 - APS
We derive a formula for the electric polarization of interacting insulators, expressed in terms
of the full Green's and vertex functions. We exemplify this method in the half-filled ionic …

Metal–insulator transitions in the half-filled ionic Hubbard model

AT Hoang - Journal of physics: Condensed matter, 2010 - iopscience.iop.org
We study electronic phase transitions in the half-filled ionic Hubbard model with an on-site
Coulomb repulsion U and an ionic energy Δ by using the coherent potential approximation …