Related papers: Universal Conductivity in the Two dimensional Boso…
Using the exact Bose-Fermi mapping, we study universal properties of ground-state density distributions and finite-temperature quantum critical behavior of one-dimensional hard-core bosons in trapped incommensurate optical lattices. Through…
We explore the possible occurrence of $\sigma$-$\omega$ condensation in the Quantum Hadro-Dynamics (QHD), namely the Serot and Walecka model, finding that at the mean field level it corresponds to a critical value of the coupling constant…
The optical conductivity of the one-band Hubbard model is calculated using the 'Dynamical Cluster Approximation' implementation of dynamical mean field theory for parameters appropriate to high temperature copper-oxide superconductors. The…
Within the BCS theory of superconductivity we calculate the superconducting gap at zero temperature for metallic hydrogen-graphene system in order to estimate the superconducting critical temperature of quasi two dimensional highly oriented…
We study the Bose-Hubbard model in the presence of on-site disorder in the canonical ensemble and conclude that the local density of the Bose glass phase behaves differently at incommensurate filling than it does at commensurate one.…
We construct a $6$ derivative holographic superconductor model in the $4$-dimensional bulk spacetimes, in which the normal state describes a quantum critical (QC) phase. The phase diagram $(\gamma_1,\hat{T}_c)$ and the condensation as the…
Using a generalized reciprocity relation between charge and vortex conductivities at complex frequencies in two space dimensions, we identify the capacitance in the insulating phase as a measure of vortex condensate stiffness. We compute…
The conductivity in quasi two-dimensional systems is calculated using the quantum kinetic equation. Linearizing the Lenard-Balescu collision integral with the extension to include external field dependences allows one to calculate the…
We study the behavior of the phase transitions of the Ziff-Gullari-Barshad (ZGB) model when the $CO$ molecules are adsorbed on the catalytic surface with a rate $y$ and desorbed from the surface with a rate $k$. We employ large-scale…
The two-dimensional Hubbard model is studied for small values of the interaction strength (U of the order of the hopping amplitude t), using a variational ansatz well suited for this regime. The wave function, a refined Gutzwiller ansatz,…
Exact formulas for the optical conductivity and the Hall conductivity of the two dimensional Hubbard model are derived in terms of an effective theory description of the local moment fluctuation in the system. In this framework, the quantum…
We report the electrical, magnetic and thermal measurements on a layered cobalt oxyhydrate Na$_{0.31}$CoO$_{2}\cdot$1.3H$_{2}$O. Bulk superconductivity at 4.3 K has been confirmed, however, the measured superconducting fraction is…
We report results of quantum Monte Carlo simulations of the Bose-Hubbard model in three dimensions. Critical parameters for the superfluid-to-Mott-insulator transition are determined with significantly higher accuracy than it has been done…
We modify a nonlinear sigma model (NLSM) for the description of a granulated disordered system in the presence of both the Coulomb repulsion and the Cooper pairing. We show that under certain controlled approximations this model is reduced…
The superfluid density rho_s(T) = 1/lambda^2(T) has been measured at 2.64 GHz in highly underdoped YBCO, at 37 dopings with T_c between 3 K and 17 K. Within limits set by the transition width Delta T_c ~ 0.4 K, rho_s(T) shows no evidence of…
We present a nonperturbative renormalization-group approach to the Bose-Hubbard model. By taking as initial condition of the renormalization-group flow the (local) limit of decoupled sites, we take into account both local and long-distance…
We consider the bilocal conductivity tensor, the two-probe conductance and its fluctuations for a disordered phase-coherent two-dimensional system of non-interacting electrons in the presence of a magnetic field, including correctly the…
A system of coupled photonic cavities on a two-dimensional square lattice is systematically investigated using the stochastic series expansion quantum Monte Carlo method. The ground state phase diagram contains insulating phases with…
Using molecular dynamics simulations, we study supercritical fluids near the gas-liquid critical point under heat flow in two dimensions. We calculate the steady-state temperature and density profiles. The resultant thermal conductivity…
Electrical resistivity experiments show superconductivity at $T_c = 1.1\,$K in a high-quality single crystal of trigonal $\gamma$-PtBi$_2$, with an enhanced critical magnetic field $\mu_0H_{c2}(0) \gtrsim 1.5\,$Tesla and a low critical…