Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

arXiv:1106.4559 · Physical Review A

Low-temperature properties of the infinite-dimensional attractive Hubbard model

Akihisa Koga, Philipp Werner

Published Aug 29, 2011• 50 citations
arXivHTMLPDF

Abstract

We investigate the attractive Hubbard model in infinite spatial dimensions by combining dynamical mean-field theory with a strong-coupling continuous-time quantum Monte Carlo method. By calculating the superfluid order parameter and the density of states, we discuss the stability of the superfluid state. In the intermediate-coupling region above the critical temperature, the density of states exhibits a heavy fermion behavior with a quasiparticle peak in the dense system, while a dip structure appears in the dilute system. The formation of the superfluid gap is also addressed.

DOI
10.1103/physreva.84.023638

Related papers

PSEUDOGAP BEHAVIOR IN THE INFINITE DIMENSIONAL ATTRACTIVE HUBBARD MODEL

Akihisa Koga, Philipp Werner

We study the attractive Hubbard model in infinite spatial dimensions by means of dynamical mean-field theory with continuous-time quantum Monte Carlo simulations. Calculating the pair potential and the spectral function, we discuss the stability of the superfluid state at low temperatures. The pseudogap behavior above the critical temperature is also addressed.

Modern Physics Letters B•May 23, 2011•1 citation

Polarized Superfluidity in the Imbalanced Attractive Hubbard Model

Akihisa Koga, Philipp Werner

We investigate the attractive Hubbard model in infinite spatial dimensions by means of dynamical mean-field theory. Using a continuous-time Monte Carlo algorithm in the Nambu formalism as an impurity solver, we directly deal with the superfluid phase in the population imbalanced system. By calculating the superfluid order parameter, the magnetization, and the density of states, we discuss how the polarized superfluid state is realized in the attractive Hubbard model at quarter filling. We find that a drastic change in the density of states is induced by spin imbalanced populations in the superfluid state.

arXiv:1002.2958•Journal of the Physical Society of Japan•May 25, 2010•26 citations

Spontaneously Symmetry-Breaking States in the Attractive SU(N) Hubbard Model

Akihisa Koga, Hiromasa Yanatori

We investigate spontaneously symmetry breaking states in the attractive SU($N$) Hubbard model at half filling. Combining dynamical mean-field theory with the continuous-time quantum Monte Carlo method, we obtain the finite temperature phase diagrams for the superfluid state. When $N>2$, the second-order phase transition occurs in the weak coupling region, while the first-order phase transition with the hysteresis appears in the strong coupling region. We also discuss the stability of the density wave state and clarify the component dependence of the maximum critical temperature.

arXiv:1612.06384•Journal of the Physical Society of Japan•Feb 3, 2017•14 citations

Dynamical properties of ultracold fermions with attractive interactions in an optical lattice

Akihisa Koga, Philipp Werner

We study dynamical properties of ultracold fermions with attractive interactions by means of dynamical mean-field theory and a continuous-time quantum Monte Carlo method. By calculating the pair potential and the density of states, we discuss the stability of the superfluid state. We also show that when holes are doped into the fermionic optical lattice system with intermediate interaction strength, the quasi-particle peak smears and a gap structure instead appears in the dilute system.

Journal of Physics Conference Series•Dec 14, 2012•0 citations

Superfluid gap formation in a fermionic optical lattice with spin imbalanced populations

Akihisa Koga, Philipp Werner

We investigate the attractive Hubbard model in infinite spatial dimensions at quarter filling. By combining dynamical mean-field theory with continuous-time quantum Monte Carlo simulations in the Nambu formalism, we directly deal with the superfluid phase in the population imbalanced system. We discuss the low energy properties in the polarized superfluid state and the pseudogap behavior in the vicinity of the critical temperature.

arXiv:1007.3307•Journal of Physics Conference Series•Jan 1, 2011•0 citations

Attractive Hubbard model on a honeycomb lattice: Quantum Monte Carlo study

Kean Loon Lee, Karim Bouadim, G. G. Batrouni +4 more

We study the attractive fermionic Hubbard model on a honeycomb lattice using determinantal quantum Monte Carlo simulations. By increasing the interaction strength $U$ (relative to the hopping parameter $t$) at half filling and zero temperature, the system undergoes a quantum phase transition at $5.0<{U}_{c}/t<5.1$ from a semimetal to a phase displaying simultaneously superfluid behavior and density order. Doping away from half filling, and increasing the interaction strength at finite but low temperature $T$, the system always appears to be a superfluid exhibiting a crossover between a BCS and a molecular regime. These different regimes are analyzed by studying the spectral function. The formation of pairs and the emergence of phase coherence throughout the sample are studied as $U$ is increased and $T$ is lowered.

arXiv:0909.2987•Physical Review B•Dec 23, 2009•24 citations
We investigate the attractive Hubbard model in infinite spatial dimensions by combining dynamical mean-field theory with a strong-coupling continuous-time quantum Monte Carlo method. By calculating the superfluid order parameter and the density of states, we discuss the stability of the superfluid state. In the intermediate-coupling region above the critical temperature, the density of states exhibits a heavy fermion behavior with a quasiparticle peak in the dense system, while a dip structure appears in the dilute system. The formation of the superfluid gap is also addressed.
We investigate the attractive Hubbard model in infinite spatial dimensions by means of dynamical mean-field theory. Using a continuous-time Monte Carlo algorithm in the Nambu formalism as an impurity solver, we directly deal with the superfluid phase in the population imbalanced system. By calculating the superfluid order parameter, the magnetization, and the density of states, we discuss how the polarized superfluid state is realized in the attractive Hubbard model at quarter filling. We find that a drastic change in the density of states is induced by spin imbalanced populations in the superfluid state.
We investigate spontaneously symmetry breaking states in the attractive SU(NNN) Hubbard model at half filling. Combining dynamical mean-field theory with the continuous-time quantum Monte Carlo method, we obtain the finite temperature phase diagrams for the superfluid state. When N>2N>2N>2, the second-order phase transition occurs in the weak coupling region, while the first-order phase transition with the hysteresis appears in the strong coupling region. We also discuss the stability of the density wave state and clarify the component dependence of the maximum critical temperature.
We study the attractive fermionic Hubbard model on a honeycomb lattice using determinantal quantum Monte Carlo simulations. By increasing the interaction strength UUU (relative to the hopping parameter ttt) at half filling and zero temperature, the system undergoes a quantum phase transition at 5.0<Uc/t<5.15.0<{U}_{c}/t<5.15.0<Uc​/t<5.1 from a semimetal to a phase displaying simultaneously superfluid behavior and density order. Doping away from half filling, and increasing the interaction strength at finite but low temperature TTT, the system always appears to be a superfluid exhibiting a crossover between a BCS and a molecular regime. These different regimes are analyzed by studying the spectral function. The formation of pairs and the emergence of phase coherence throughout the sample are studied as UUU is increased and TTT is lowered.