arXiv subjects

Tony C Scott

Publications and source records attributed to Tony C Scott.

3 recordsLinked to original sources

arXiv2020

Worm quantum Monte-Carlo study of phase diagram of extended Jaynes-Cummings-Hubbard model

Herein, we study the extended Jaynes-Cummings-Hubbard model mainly by the large-scale worm quantum Monte-Carlo method to check whether or not a light supersolid phase exists in various geometries, such as the one-dimensional chain, square lattices and triangular lattices. To achieve our purpose, the ground state phase diagrams are investigated. For the one-dimensional chain and square lattices, a first-order transition occurs between the superfluid phase and the solid phase and therefore there is no stable supersolid phase existing in these geometries. Interestingly, soliton/beats of the local densities arise if the chemical potential is adjusted in the finite-size chain. However, this soliton-superfluid coexistence can not be considered as a supersolid in the thermodynamic limit. Searching for a light supersolid, we also studied the Jaynes-Cummings-Hubbard model on triangular lattices, and the phase diagrams are obtained. Through measurement of the structural factor, momentum distribution and superfluid stiffness for various system sizes, a supersolid phase exists stably in the triangular lattices geometry and the regime of the supersolid phase is smaller than that of the mean field results. The light supersolid in the Jaynes-Cummings-Hubbard model is attractive because it has superreliance, which is absent in the pure Bose-Hubbard model. We believe the results in this paper could help search for new novel phases in cold-atom experiments

cond-mat.stat-mech↗

arXiv2017

Ground State Properties of the One-Dimensional Unconstrained Pseudo-Anyon Hubbard Model

We study the (pseudo-) anyon Hubbard model on a one-dimensional lattice without the presence of a three-body hardcore constraint. In particular, for the pseudo-fermion limit of a large statistical angle $θ\approxπ$, we observe a wealth of exotic properties including {a first order transition} between different superfluid phases and a {two-component} partially paired phase for large fillings without need of an additional three-body hardcore constraint.In this limit, we analyze the effect of an induced hardcore constraint, which leads to the stabilization of superfluid {ground states} for vanishing or even small attractive on-site interactions. For finite statistical angles, we study the unconventional broken-symmetry superfluid peaked at a finite momentum, resulting in an interesting beat phenomenon of single particle correlation functions.We show how some features of various ground state phases, including an analog of the partially paired phase in the pseudo-fermion limit, may be reproduced in a naive mean field frame.

cond-mat.quant-gas↗

arXiv2016

Beats, broken-symmetry superfluid on a one dimensional anyon Hubbard model

By using the density matrix renormalization group and mean field methods, the anyon Hubbard model is studied systematically on a one dimensional lattice. The model can be expressed as a Bose-Hubbard model with a density-dependent-phase term. When the phase angle is $θ=0$ or $θ=π$, the model will be equivalent to boson and pseudo fermion models, respectively. In the mean field frame, we find a broken-symmetry superfluid (BSF), in which the $b^{\dagger}(b)$ operators on the nearest neighborhood sites have exactly opposite directions and behave like a directed oscillation pattern. By the density matrix reorganization group method, in the broken-symmetry superfluid, both the real and imaginary parts of the correlation $b^{\dagger}_ib_{i+r}$ behave according to a {\it beat phenomenon} with $0<θ<π$ in the form $C_0e^{i k r}(-1)^{r}$ or behave like waves with different wavelengths in the form $C_0e^{i k r}$. The distributions of the broken-symmetry superfluid phase and other phases are shown in the phase diagrams with different values of $θ$ and the direct phase transition between the two types of superfluid is observed. The beats phenomenon is explained by double peaks of momentum distribution with two wave numbers ${k}_1$ and ${k}_2$ satisfying the condition $\frac{{k}_1-{k}_2}{{k}_1+{k}_2}<\frac{1}{3}$, which are expected to be observed in the optical experiments.

cond-mat.quant-gas↗