The study of ultracold optically trapped atoms has opened new vistas in the physics of correlated quantum systems. Much attention has now turned to mixtures of bosonic and fermionic atoms. A central puzzle is the disagreement between the experimental observation of a reduced bosonic visibility ${\mathcal{V}}_{b}$ , and quantum Monte Carlo (QMC) calculations which show ${\mathcal{V}}_{b}$ increasing. In this paper, we present QMC simulations which evaluate the density profiles and ${\mathcal{V}}_{b}$ of mixtures of bosons and fermions in one-dimensional optical lattices. We resolve the discrepancy between theory and experiment by identifying parameter regimes where ${\mathcal{V}}_{b}$ is reduced, and where it is increased. We present a simple qualitative picture of the different response to the fermion admixture in terms of the superfluid and Mott-insulating domains before and after the fermions are included. Finally, we show that ${\mathcal{V}}_{b}$ exhibits kinks which are tied to the domain evolution present in the pure case, and also additional structure arising from the formation of boson-fermion molecules, a prediction for future experiments.The study of ultracold optically trapped atoms has opened new vistas in the physics of correlated quantum systems. Much attention has now turned to mixtures of bosonic and fermionic atoms. A central puzzle is the disagreement between the experimental observation of a reduced bosonic visibility ${\mathcal{V}}_{b}$, and quantum Monte Carlo (QMC) calculations which show ${\mathcal{V}}_{b}$ increasing. In this paper, we present QMC simulations which evaluate the density profiles and ${\mathcal{V}}_{b}$ of mixtures of bosons and fermions in one-dimensional optical lattices. We resolve the discrepancy between theory and experiment by identifying parameter regimes where ${\mathcal{V}}_{b}$ is reduced, and where it is increased. We present a simple qualitative picture of the different response to the fermion admixture in terms of the superfluid and Mott-insulating domains before and after the fermions are included. Finally, we show that ${\mathcal{V}}_{b}$ exhibits kinks which are tied to the domain evolution present in the pure case, and also additional structure arising from the formation of boson-fermion molecules, a prediction for future experiments.

arXiv:0711.0968Physical Review AApr 23, 200821 citations

Quantum-Monte-Carlo simulations for fermionic systems

I. Morgenstern

The European Physical Journal BJun 1, 198914 citations

Quantum Monte Carlo Simulations of Correlated-Electron Models

Shiwei Zhang

APSMay 1, 19960 citations

Quantum Monte Carlo methods in condensed matter physics

Masuo Suzuki

The Quantum Transfer Matrix and Its Application to Quantum Spin Chains (K Kubo) Transfer Matrices in Quantum Many-Body Systems (T Koma) Monte Carlo Calculations of Elementary Excitation (M Takahashi) The Decoupled Cell Method of Quantum Monte Carlo Calculation (S Homma) Decoupled Cell Monte Carlo Study of the Critical Properties of the Spin-1/2 Ferromagnetic Heisenberg Model in Three Dimensions (R J Creswick & C J Sisson) Variational Monte Carlo Studies of Correlated Electrons (H Shiba) Quantum Monte Carlo Simulation of Multiband Fermion Systems and Its Application to Superconductivity (K Kuroki & H Aoki) Quantum Monte Carlo in the Infinite Dimensional Limit (M Jarrell et al) Aspects of the Sign Problem (J H Samson) Ground-State Projection Using Auxiliary Fields (S Fahy) Fermion Simulations of Correlated Systems (M Imada) Dirty Bosons in 2D: Phases and Phase Transitions (N Trivedi & M Makivi'c). (Part Contents).The Quantum Transfer Matrix and Its Application to Quantum Spin Chains (K Kubo) Transfer Matrices in Quantum Many-Body Systems (T Koma) Monte Carlo Calculations of Elementary Excitation (M Takahashi) The Decoupled Cell Method of Quantum Monte Carlo Calculation (S Homma) Decoupled Cell Monte Carlo Study of the Critical Properties of the Spin-1/2 Ferromagnetic Heisenberg Model in Three Dimensions (R J Creswick & C J Sisson) Variational Monte Carlo Studies of Correlated Electrons (H Shiba) Quantum Monte Carlo Simulation of Multiband Fermion Systems and Its Application to Superconductivity (K Kuroki & H Aoki) Quantum Monte Carlo in the Infinite Dimensional Limit (M Jarrell et al) Aspects of the Sign Problem (J H Samson) Ground-State Projection Using Auxiliary Fields (S Fahy) Fermion Simulations of Correlated Systems (M Imada) Dirty Bosons in 2D: Phases and Phase Transitions (N Trivedi & M Makivi'c). (Part Contents).

WORLD SCIENTIFIC eBooksJan 1, 19930 citations

Discovering correlated fermions using quantum Monte Carlo

Lucas K. Wagner, David M. Ceperley

It has become increasingly feasible to use quantum Monte Carlo (QMC) methods to study correlated fermion systems for realistic Hamiltonians. We give a summary of these techniques targeted at researchers in the field of correlated electrons, focusing on the fundamentals, capabilities, and current status of this technique. The QMC methods often offer the highest accuracy solutions available for systems in the continuum, and, since they address the many-body problem directly, the simulations can be analyzed to obtain insight into the nature of correlated quantum behavior.It has become increasingly feasible to use quantum Monte Carlo (QMC) methods to study correlated fermion systems for realistic Hamiltonians. We give a summary of these techniques targeted at researchers in the field of correlated electrons, focusing on the fundamentals, capabilities, and current status of this technique. The QMC methods often offer the highest accuracy solutions available for systems in the continuum, and, since they address the many-body problem directly, the simulations can be analyzed to obtain insight into the nature of correlated quantum behavior.

arXiv:1602.01344Reports on Progress in PhysicsAug 12, 201676 citations

Quantum Monte Carlo Studies of Strongly Interacting Fermionic Systems

Lucas Madeira

Jan 1, 20180 citations

{\mathcal{V}}_{b}

, and quantum Monte Carlo (QMC) calculations which show

{\mathcal{V}}_{b}

increasing. In this paper, we present QMC simulations which evaluate the density profiles and

{\mathcal{V}}_{b}

of mixtures of bosons and fermions in one-dimensional optical lattices. We resolve the discrepancy between theory and experiment by identifying parameter regimes where

{\mathcal{V}}_{b}

is reduced, and where it is increased. We present a simple qualitative picture of the different response to the fermion admixture in terms of the superfluid and Mott-insulating domains before and after the fermions are included. Finally, we show that

{\mathcal{V}}_{b}

exhibits kinks which are tied to the domain evolution present in the pure case, and also additional structure arising from the formation of boson-fermion molecules, a prediction for future experiments.