Isentropes of spin-1 bosons in an optical lattice (2009)
Mahmud, K. W., Batrouni, G. G., Scalettar, R. T.
We analyze the effects of adiabatic ramping of optical lattices on the temperature of spin-1 bosons in a homogeneous lattice. Using mean-field theory, we present the isentropes in the...
Attractive Hubbard Model on a Honeycomb Lattice (2009)
Lee, K. L., Bouadim, K., Batrouni, G. G., Hebert, F., Scalettar, R. T., Miniatura, C., ...
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...
Quantum Criticality Due to Incipient Phase Separation in the Two-dimensional Hubbard Model (2009)
Khatami, E., Mikelsons, K., Galanakis, D., Macridin, A., Moreno, J., Scalettar, R. T., ...
We investigate the two-dimensional Hubbard model with next-nearest-neighbor hopping, t', using the dynamical cluster approximation. We confirm the existence of a first order phase separation (PS)...
The screening of 4f moments and delocalization in the compressed light rare earths (2009)
McMahan, A. K., Scalettar, R. T., Jarrell, M.
Spin and charge susceptibilities and the 4f^n, 4f^{n-1}, and 4f^{n+1} configuration weights are calculated for compressed Ce (n=1), Pr (n=2), and Nd (n=3) metals using dynamical mean field theory...
Parquet approximation for the 4x4 Hubbard cluster (2009)
Yang, S. X., Fotso, H., Liu, J., Maier, T. A., Tomko, K., D'Azevedo, E. F., ...
We present a numerical solution of the parquet approximation (PA), a conserving diagrammatic approach which is self-consistent at both the single-particle and the two-particle levels. The fully...
Dynamical Mean Field Theory Cluster Solver with Linear Scaling in Inverse Temperature (2009)
Khatami, E., Lee, C. R., Bai, Z. J., Scalettar, R. T., Jarrell, M.
Dynamical mean field theory and its cluster extensions provide a very useful approach for examining phase transitions in model Hamiltonians, and, in combination with electronic structure theory,...
High Precision Quantum Monte Carlo Study of the 2D Fermion Hubbard Model (2009)
Varney, C. N., Lee, C. -R., Bai, Z. J., Chiesa, S., Jarrell, M., Scalettar, R. T.
We report large scale determinant Quantum Monte Carlo calculations of the effective bandwidth, momentum distribution, and magnetic correlations of the square lattice fermion Hubbard Hamiltonian at...
Magnetic and Superfluid Transitions in the d=1 Spin-1 Boson Hubbard Model (2008)
Batrouni, G. G., Rousseau, V. G., Scalettar, R. T.
The interplay between magnetism and metal-insulator transitions is fundamental to the rich physics of the single band fermion Hubbard model (FHM). Recent progress in experiments on trapped ultra-cold...
Monte Carlo Study of an Inhomogeneous Blume-Capel Model (2008)
Pittman, S. M., Batrouni, G. G., Scalettar, R. T.
Systems of particles in a confining potential exhibit a spatially dependent density which fundamentally alters the nature of phase transitions that occur. A specific instance of this situation, which...
Disordered two-dimensional superconductors: roles of temperature and interaction strength (2008)
Mondaini, Felipe, Paiva, Thereza, Santos, Raimundo R. Dos, Scalettar, R. T.
We have considered the half-filled disordered attractive Hubbard model on a square lattice, in which the on-site attraction is switched off on a fraction $f$ of sites, while keeping a finite $U$ on...
High-energy anomaly dichotomy in electron- and hole-doped high temperature superconductors (2008)
Moritz, B., Schmitt, F., Meevasana, W., Johnston, S., Motoyama, E. M., Greven, M., ...
New results are presented from angle-resolved photoemission spectroscopy on the electron-doped cuprate Nd_1.83Ce_0.17CuO_4 that show a high energy anomaly in the dispersion around 500-600 meV,...
Batrouni, G. G., Krishnamurthy, H. R., Mahmud, K. W., Rousseau, V. G., Scalettar, R. T.
Quantum Monte Carlo (QMC) simulations and the Local Density Approximation (LDA) are used to map the constant particle number (canonical) trajectories of the Bose Hubbard Hamiltonian confined in a...
Magnetic and Transport Properties of a Coupled Hubbard Bilayer with Electron and Hole Doping (2008)
Bouadim, K., Batrouni, G. G., Hebert, F., Scalettar, R. T.
The single band, two dimensional Hubbard Hamiltonian has been extensively studied as a model for high temperature superconductivity. While Quantum Monte Carlo simulations within the dynamic cluster...
Superfluid and Mott Insulator phases of one-dimensional Bose-Fermi mixtures (2007)
Zujev, A., Baldwin, A., Scalettar, R. T., Rousseau, V. G., Denteneer, P. J. H., Rigol, M.
We study the ground state phases of Bose-Fermi mixtures in one-dimensional optical lattices with quantum Monte Carlo simulations using the Canonical Worm algorithm. Depending on the filling of bosons...
The Effect of Randomness on Long Range Order in the Two-Dimensional Half-Filled Hubbard (2007)
C. Huscroft, R.T. Scalettar, M. Ulmke
. Quantum Monte Carlo simulations are used to determine the effects of disorder on magnetic, charge density wave, and superconducting correlations in the two--dimensional half--filled Hubbard model....
Quantum Monte Carlo study of the visibility of one-dimensional Bose-Fermi mixtures (2007)
Varney, C. N., Rousseau, V. G., Scalettar, R. T.
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...
Exact Numerical Study of Pair Formation with Imbalanced Fermion Populations (2007)
Batrouni, G. G., Huntley, M. H., Rousseau, V. G., Scalettar, R. T.
We present an exact Quantum Monte Carlo study of the attractive 1-dimensional Hubbard model with imbalanced fermion population. The pair-pair correlation function, which decays monotonically in the...
Quantum Monte Carlo Study of a Dynamic Hubbard Model (2007)
Bouadim, K., Enjalran, M., Hebert, F., Batrouni, G. G., Scalettar, R. T.
The `dynamic' Hubbard Hamiltonian describes interacting fermions on a lattice whose on-site repulsion is modulated by a coupling to a fluctuating bosonic field. We investigate one such model,...
Aryanpour, K., Paiva, T., Pickett, W. E., Scalettar, R. T.
We study s-wave superconductivity in the two-dimensional square lattice attractive Hubbard Hamiltonian for various inhomogeneous patterns of interacting sites. Using the Bogoliubov-de Gennes (BdG)...
Correlation Effects in the Triangular Lattice Single-band System Li_xNbO_2 (2007)
Lee, K. -W., Kunes, J., Scalettar, R. T., Pickett, W. E.
Superconductivity in hole-doped Li_xNbO_2 has been reported with T_c ~ 5 K in the range 0.45 < x < 0.8. The electronic structure is based on a two-dimensional triangular Nb lattice. The strong...
Monte Carlo Simulations of an Extended Feynman-Kikuchi Model (2007)
We present Quantum Monte Carlo simulations of a generalization of the Feynman-Kikuchi model which includes the possibility of vacancies and interactions between the particles undergoing exchange. By...
Static versus dynamic fluctuations in the one-dimensional extended Hubbard model (2007)
Craig, H. A., Varney, C. N., Pickett, W. E., Scalettar, R. T.
The extended Hubbard Hamiltonian is a widely accepted model for uncovering the effects of strong correlations on the phase diagram of low-dimensional systems, and a variety of theoretical techniques...
Metallic phase in the two-dimensional ionic Hubbard model (2007)
Bouadim, K., Paris, N., Hebert, F., Batrouni, G. G., Scalettar, R. T.
We investigate the phases of the ionic Hubbard model in a two-dimensional square lattice using determinant quantum Monte Carlo (DQMC). At half-filling, when the interaction strength or the staggered...
Chakraborty, P. B., Denteneer, P. J. H., Scalettar, R. T.
In this paper we present a determinant quantum monte carlo study of the two dimensional Hubbard model with random site disorder. We show that, as in the case of bond disorder, the system undergoes a...
Supersolid phases in the one dimensional extended soft core Bosonic Hubbard model (2006)
Batrouni, G. G., Hebert, F., Scalettar, R. T.
We present results of Quantum Monte Carlo simulations for the soft core extended bosonic Hubbard model in one dimension. By studying the superfluid density, the compressibility and the structure...
Exact Study of the 1D Boson Hubbard Model with a Superlattice Potential (2006)
Rousseau, V. G., Rigol, M., Hébert, F., Arovas, D. P., Batrouni, G. G., Scalettar, R. T.
We use Quantum Monte Carlo simulations and exact diagonalization to explore the phase diagram of the Bose-Hubbard model with an additional superlattice potential. We first analyze the properties of...
Quantum Monte Carlo Study of an Interaction-Driven Band Insulator to Metal Transition (2006)
Paris, N., Bouadim, K., Hebert, F., Batrouni, G. G., Scalettar, R. T.
We study the transitions from band insulator to metal to Mott insulator in the ionic Hubbard model on a two dimensional square lattice using determinant Quantum Monte Carlo. Evaluation of the...
Mott and Band Insulator Transitions in the Binary Alloy Hubbard Model (2006)
Paris, N., Baldwin, A., Scalettar, R. T.
We use determinant Quantum Monte Carlo simulations and exact diagonalization to explore insulating behavior in the Hubbard model with a bimodal distribution of randomly positioned local site...
The magnetic susceptibility of exchange-disordered antiferromagnetic finite chains (2006)
Chaves, C. M., Paiva, Thereza, Castro, J. D'Albuquerque E, Hebert, F., Scalettar, R. T., Batrouni, G. G., ...
The low-temperature behavior of the static magnetic susceptibility of exchange-disordered antiferromagnetic spin chains is investigated. It is shown that for a relatively small and even number of...
Supersolid phases in the one dimensional extended soft core Bosonic Hubbard model (2006)
Batrouni, G. G., Hebert, F., Scalettar, R. T.
We present results of Quantum Monte Carlo simulations for the soft core extended bosonic Hubbard model in one dimension exhibiting the presence of supersolid phases similar to those recently found in...
Aryanpour, K., Pickett, W. E., Scalettar, R. T.
We employ dynamical mean field theory (DMFT) with a Quantum Monte Carlo (QMC) atomic solver to investigate the finite temperature Mott transition in the Hubbard model with the nearest neighbor...
Rigol, M., Scalettar, R. T., Sengupta, P., Batrouni, G. G.
We study, using quantum Monte-Carlo simulations, the energetics of the formation of Mott domains of fermions and bosons trapped on one-dimensional lattices. We show that, in both cases, the sum of...
Mott Domains of Bosons Confined on Optical Lattices (2006)
Batrouni, G. G., Rousseau, V., Scalettar, R. T., Rigol, M., Muramatsu, A., Denteneer, P. J. H., ...
In the absence of a confining potential, the boson Hubbard model in its ground state is known to exhibit a superfluid to Mott insulator quantum phase transition at commensurate fillings and strong...
Rigol, M., Scalettar, R. T., Sengupta, P., Batrouni, G. G.
We study, using quantum Monte Carlo simulations, the energetics of the formation of Mott domains of fermions and bosons trapped on one-dimensional lattices. We show that, in both cases, the sum of...
Exact Study of the 1D Boson Hubbard Model with a Superlattice Potential (2006)
Rousseau, V. G., Arovas, D. P., Rigol, M., Hébert, F., Batrouni, G. G., Scalettar, R. T.
We use Quantum Monte Carlo simulations and exact diagonalization to explore the phase diagram of the Bose-Hubbard model with an additional superlattice potential. We first analyze the properties of...
Sengupta, P., Rigol, M., Batrouni, G. G., Denteneer, P. J. H., Scalettar, R. T.
We study the phase coherence and visibility of trapped atomic condensates on one-dimensional optical lattices, by means of quantum Monte-Carlo simulations. We obtain structures in the visibility...
Exact Study of the 1D Boson Hubbard Model with a Superlattice Potential (2006)
Rousseau, V. G., Rigol, M., Hébert, F., Arovas, D. P., Batrouni, G. G., Scalettar, R. T.
We use Quantum Monte Carlo simulations and exact diagonalization to explore the phase diagram of the Bose-Hubbard model with an additional superlattice potential. We first analyze the properties of...
Rigol, M., Scalettar, R. T., Sengupta, P., Batrouni, G. G.
We study, using quantum Monte-Carlo simulations, the energetics of the formation of Mott domains of fermions and bosons trapped on one-dimensional lattices. We show that, in both cases, the sum of...
Supersolid phases in the one dimensional extended soft core Bosonic Hubbard model (2006)
Batrouni, G. G., Hebert, F., Scalettar, R. T.
We present results of Quantum Monte Carlo simulations for the soft core extended bosonic Hubbard model in one dimension. By studying the superfluid density, the compressibility and the structure...
Superconductivity and Lattice Instability in Compressed Lithium from Fermi Surface Hot Spots (2006)
Kasinathan,D., Kuneš,J., Lazicki,A., Rosner,H., Yoo,C. S., Scalettar,R. T., ...
Supersolid phases in the one dimensional extended soft core Bosonic Hubbard model (2006)
Batrouni, G. G., Hebert, F., Scalettar, R. T.
We present results of Quantum Monte Carlo simulations for the soft core extended bosonic Hubbard model in one dimension. By studying the superfluid density, the compressibility and the structure...
Exact Study of the 1D Boson Hubbard Model with a Superlattice Potential (2006)
Rousseau, V. G., Rigol, M., Hébert, F., Arovas, D. P., Batrouni, G. G., Scalettar, R. T.
We use Quantum Monte Carlo simulations and exact diagonalization to explore the phase diagram of the Bose-Hubbard model with an additional superlattice potential. We first analyze the properties of...
Rigol, M., Scalettar, R. T., Sengupta, P., Batrouni, G. G.
We study, using quantum Monte-Carlo simulations, the energetics of the formation of Mott domains of fermions and bosons trapped on one-dimensional lattices. We show that, in both cases, the sum of...
Superconductivity and Lattice Instability in Compressed Lithium from Fermi Surface Hot Spots (2006)
Kasinathan, D., Kuneš, J., Lazicki, A., Rosner, H., Yoo, C. S., Scalettar, R. T., ...
Realistic investigations of correlated electron systems with LDA plus DMFT (2006)
Held, K., Nekrasov, I. A., Keller, G., Eyert, V., Blumer, N., McMahan, A. K., ...
Conventional band structure calculations in the local density approximation (LDA) [1-3] are highly successful for many materials, but miss important aspects of the physics and energetics of strongly...
Ring Exchange and Phase Separation in the Two-dimensional Boson Hubbard model (2005)
Rousseau, V. G., Scalettar, R. T., Batrouni, G. G.
We present Quantum Monte Carlo simulations of the soft-core bosonic Hubbard model with a ring exchange term K. For values of K which exceed roughly half the on-site repulsion U, the density is a...
Superconductivity and Lattice Instability in Compressed Lithium from Fermi Surface Hot Spots (2005)
Kasinathan, Deepa, Kunes, J., Lazicki, A., Rosner, H., Yoo, C. S., Scalettar, R. T., ...
The highest superconducting temperature T$_c$ observed in any elemental metal (Li with T$_c$ ~ 20 K at pressure P ~ 40 GPa) is shown to arise from critical (formally divergent) electron-phonon...
Dynamic response of trapped ultracold bosons on optical lattices (2005)
Batrouni, G. G., Assaad, F. F., Scalettar, R. T., Denteneer, P. J. H.
We study the dynamic response of ultracold bosons trapped in one-dimensional optical lattices using Quantum Monte Carlo simulations of the boson Hubbard model with a confining potential. The dynamic...
Sengupta, P., Rigol, M., Batrouni, G. G., Denteneer, P. J. H., Scalettar, R. T.
We study the phase coherence and visibility of trapped atomic condensates on one-dimensional optical lattices, by means of quantum Monte-Carlo simulations. We obtain structures in the visibility...
Effect of inhomogeneity on s-wave superconductivity in the attractive Hubbard model (2005)
Aryanpour, K., Dagotto, E. R., Mayr, M., Paiva, T., Pickett, W. E., Scalettar, R. T.
Inhomogeneous s-wave superconductivity is studied in the two-dimensional, square lattice attractive Hubbard Hamiltonian using the Bogoliubov-de Gennes (BdG) mean field approximation. We find that at...
The magnetic susceptibility of exchange-disordered antiferromagnetic finite chains (2005)
Chaves, C. M., Paiva, Thereza, Castro, J. D'Albuquerque E, Hebert, F., Scalettar, R. T., Batrouni, G. G., ...
The low-temperature behavior of the static magnetic susceptibility $\chi(T)$ of exchange-disordered antiferromagnetic spin chains is investigated. It is shown that for a relatively small and even...
Ring Exchange and Phase Separation in the Two-dimensional Boson Hubbard model (2005)
Rousseau, V. G., Scalettar, R. T., Batrouni, G. G.
We present Quantum Monte Carlo simulations of the soft-core bosonic Hubbard model with a ring exchange term K. For values of K which exceed roughly half the on-site repulsion U, the density is a...
Dynamic response of trapped ultracold bosons on optical lattices (2005)
Batrouni, G. G., Assaad, F. F., Scalettar, R. T., Denteneer, P. J. H.
We study the dynamic response of ultracold bosons trapped in one-dimensional optical lattices using Quantum Monte Carlo simulations of the boson Hubbard model with a confining potential. The dynamic...
Collective Oscillations of Strongly Correlated One-Dimensional Bosons on a Lattice (2005)
Rigol, M., Rousseau, V., Scalettar, R. T., Singh, R. R. P.
We study the dipole oscillations of strongly correlated 1D bosons, in the hard-core limit, on a lattice, by an exact numerical approach. We show that far from the regime where a Mott insulator...
Rigol, M., Manmana, S. R., Muramatsu, A., Scalettar, R. T., Singh, R. R. P., Wessel, S.
In a recent letter Machida et al. [Phys. Rev. Lett. 93, 200402 (2004)] concluded that in a trapped gas of fermions with repulsive interactions a superfluid phase appears around the Mott-insulator at...
Ring Exchange and Phase Separation in the Two-dimensional Boson Hubbard model (2005)
Rousseau, V. G., Scalettar, R. T., Batrouni, G. G.
We present Quantum Monte Carlo simulations of the soft-core bosonic Hubbard model with a ring exchange term K. For values of K which exceed roughly half the on-site repulsion U, the density is a...
Solitons in trapped Bose-Einstein condensates in one-dimensional optical lattices (2005)
Hebert, F., Batrouni, G. G., Scalettar, R. T.
We use quantum Monte Carlo simulations to show the presence and study the properties of solitons in the one-dimensional soft-core bosonic Hubbard model with near-neighbor interaction in traps. We...
Sengupta, P., Rigol, M., Batrouni, G. G., Denteneer, P. J. H., Scalettar, R. T.
We study the phase coherence and visibility of trapped atomic condensates on one-dimensional optical lattices, by means of quantum Monte-Carlo simulations. We obtain structures in the visibility...
The magnetic susceptibility of exchange-disordered antiferromagnetic finite chains (2005)
Chaves, C. M., Paiva, Thereza, Castro, J. D'Albuquerque E, Hebert, F., Scalettar, R. T., Batrouni, G. G., ...
The low-temperature behavior of the static magnetic susceptibility of exchange-disordered antiferromagnetic spin chains is investigated. It is shown that for a relatively small and even number of...
Dynamic response of trapped ultracold bosons on optical lattices (2005)
Batrouni, G. G., Assaad, F. F., Scalettar, R. T., Denteneer, P. J. H.
We study the dynamic response of ultracold bosons trapped in one-dimensional optical lattices using Quantum Monte Carlo simulations of the boson Hubbard model with a confining potential. The dynamic...
Ring Exchange and Phase Separation in the Two-dimensional Boson Hubbard model (2005)
Rousseau, V. G., Scalettar, R. T., Batrouni, G. G.
We present Quantum Monte Carlo simulations of the soft-core bosonic Hubbard model with a ring exchange term K. For values of K which exceed roughly half the on-site repulsion U, the density is a...
Sengupta, P., Rigol, M., Batrouni, G. G., Denteneer, P. J. H., Scalettar, R. T.
We study the phase coherence and visibility of trapped atomic condensates on one-dimensional optical lattices, by means of quantum Monte-Carlo simulations. We obtain structures in the visibility...
The magnetic susceptibility of exchange-disordered antiferromagnetic finite chains (2005)
Chaves, C. M., Paiva, Thereza, Castro, J. D'Albuquerque E, Hebert, F., Scalettar, R. T., Batrouni, G. G., ...
The low-temperature behavior of the static magnetic susceptibility of exchange-disordered antiferromagnetic spin chains is investigated. It is shown that for a relatively small and even number of...
Dynamic response of trapped ultracold bosons on optical lattices (2005)
Batrouni, G. G., Assaad, F. F., Scalettar, R. T., Denteneer, P. J. H.
We study the dynamic response of ultracold bosons trapped in one-dimensional optical lattices using Quantum Monte Carlo simulations of the boson Hubbard model with a confining potential. The dynamic...
Solitons in Trapped Bose-Einstein condensates in one-dimensional optical lattices (2004)
Hebert, F., Batrouni, G. G., Scalettar, R. T.
We use Quantum Monte Carlo simulations to show the presence and study the properties of solitons in the one dimensional soft-core bosonic Hubbard model with near neighbor interaction in traps. We...
Critical Properties of an Ising Model with Dilute Long-range Interactions (2004)
Statistical mechanical models with local interactions in $d>1$ dimension can be regarded as $d=1$ dimensional models with regular long range interactions. In this paper we study the critical...
Paiva, Thereza, Scalettar, R. T., Zheng, W., Singh, R. R. P., Oitmaa, J.
We investigate ground state and finite temperature properties of the half-filled Hubbard model on a honeycomb lattice using quantum monte carlo and series expansion techniques. Unlike the square...
Reentrant Disordering of Colloidal Molecular Crystals on 2D Periodic Substrates (2004)
Mikulis, M., Reichhardt, C. J. Olson, Reichhardt, C., Scalettar, R. T., Zimanyi, G. T.
We study colloidal ordering and disordering on two-dimensional periodic substrates where the number of colloids per substrate minima is two or three. The colloids form dimer or trimer states with...
Critical temperature for the two-dimensional attractive Hubbard Model (2004)
Paiva, Thereza, Santos, Raimundo R. Dos, Scalettar, R. T., Denteneer, P. J. H.
The critical temperature for the attractive Hubbard model on a square lattice is determined from the analysis of two independent quantities, the helicity modulus, $\rho_s$, and the pairing...
Domain regime in two-dimensional disordered vortex matter (2004)
Chandran, Mahesh, Scalettar, R. T., Zimanyi, G. T.
A detailed numerical study of the real space configuration of vortices in disordered superconductors using 2D London-Langevin model is presented. The magnetic field $B$ is varied between 0 and...
Phase separation in the bosonic Hubbard model with ring exchange (2003)
Rousseau, V., Batrouni, G. G., Scalettar, R. T.
We show that soft core bosons in two dimensions with a ring exchange term exhibit a tendency for phase separation. This observation suggests that the thermodynamic stability of normal bose liquid...
Reversal-field memory in magnetic hysteresis (2003)
Katzgraber, H. G., Pazmandi, F., Pike, C. R., Liu, Kai, Scalettar, R. T., Verosub, K. L., ...
We report results demonstrating a singularity in the hysteresis of magnetic materials, the reversal-field memory effect. This effect creates a nonanalyticity in the magnetization curves at a...
Metastability and Transient Effects in Vortex Matter Near a Decoupling Transition (2003)
Olson, C. J., Reichhardt, C., Scalettar, R. T., Zimanyi, G. T., Gronbech-Jensen, N.
We examine metastable and transient effects both above and below the first-order decoupling line in a 3D simulation of magnetically interacting pancake vortices. We observe pronounced transient and...
Local quantum criticality in confined fermions on optical lattices (2003)
Rigol, M., Muramatsu, A., Batrouni, G. G., Scalettar, R. T.
Using quantum Monte Carlo simulations, we show that the one-dimensional fermionic Hubbard model in a harmonic potential displays quantum critical behavior at the boundaries of a Mott-insulating...
Dynamic transition in driven vortices across the peak effect in superconductors (2003)
Chandran, Mahesh, Scalettar, R. T., Zimanyi, G. T.
We study the zero-temperature dynamic transition from the disordered flow to an ordered flow state in driven vortices in type-II superconductors. The transition current $I_{p}$ is marked by a sharp...
Denteneer, P. J. H., Scalettar, R. T.
The effect of a Zeeman magnetic field coupled to the spin of the electrons on the conducting properties of the disordered Hubbard model is studied. Using the Determinant Quantum Monte Carlo method,...
Realistic investigations of correlated electron systems with LDA+DMFT (2003)
Held, K., Nekrasov, I. A., Keller, G., Eyert, V., Blümer, N., McMahan, A. K., ...
McMahan, A. K., Held, K., Scalettar, R. T.
We have calculated thermodynamic and spectral properties of Ce metal over a wide range of volume and temperature, including the effects of 4f electron correlations, by the merger of the local density...
Superconductivity Induced by Negative Centers (2002)
Litak, G., Paiva, T., Scalettar, R. T., Huscroft, C., Santos, R. R. Dos
We study the effect of random dilution of attraction centers on electron pairing in a generalization of the negative $U$ Hubbard model where the interaction $U_i$, defined on the two dimensional...
Ku, Wei, Rosner, H., Pickett, W. E., Scalettar, R. T.
Microscopic mechanisms of the puzzling insulating ferromagnetism of half-filled La$_{4}$Ba$_{2}$Cu$_{2}$O$_{10}$ are elucidated with energy-resolved Wannier states. The dominant magnetic coupling,...
Reversal-Field Memory in the Hysteresis of Spin Glasses (2002)
Katzgraber, H. G., Pazmandi, F., Pike, C. R., Liu, Kai, Scalettar, R. T., Verosub, K. L., ...
We report a novel singularity in the hysteresis of spin glasses, the reversal-field memory effect, which creates a non-analyticity in the magnetization curves at a particular point related to the...
Metastability and uniqueness of vortex states at depinning (2002)
Chandran, Mahesh, Scalettar, R. T., Zimanyi, G. T.
We present results from numerical simulations of transport of vortices in the zero-field cooled (ZFC) and the field-cooled (FC) state of a type-II superconductor. In the absence of an applied current...
Mott Domains of Bosons Confined on Optical Lattices (2002)
Batrouni, G. G., Rousseau, V., Scalettar, R. T., Rigol, M., Muramatsu, A., Denteneer, P. J. H., ...
In the absence of a confining potential, the boson Hubbard model in its ground state is known to exhibit a superfluid to Mott insulator quantum phase transition at commensurate fillings and strong...
Mott Domains of Bosons Confined on Optical Lattices (2002)
Batrouni, G. G., Rousseau, V., Scalettar, R. T., Rigol, M., Muramatsu, A., Denteneer, P. J. H., ...
In the absence of a confining potential, the boson Hubbard model in its ground state is known to exhibit a superfluid to Mott insulator quantum phase transition at commensurate fillings and strong...
Mott Domains of Bosons Confined on Optical Lattices (2002)
Batrouni, G. G., Rousseau, V., Scalettar, R. T., Rigol, M., Muramatsu, A., Denteneer, P. J. H., ...
In the absence of a confining potential, the boson Hubbard model in its ground state is known to exhibit a superfluid to Mott insulator quantum phase transition at commensurate fillings and strong...
The LDA+DMFT Approach to Materials with Strong Electronic Correlations (2001)
Held, K., Nekrasov, I. A., Keller, G., Eyert, V., Blümer, N., McMahan, A. K., ...
LDA+DMFT is a novel computational technique for ab initio investigations of real materials with strongly correlated electrons, such as transition metals and their oxides. It combines the strength of...
The Cerium volume collapse: Results from the LDA+DMFT approach (2001)
Held, K., McMahan, A. K., Scalettar, R. T.
The merger of density-functional theory in the local density approximation (LDA) and many-body dynamical mean field theory (DMFT) allows for an ab initio calculation of Ce including the inherent 4f...
Particle-Hole Symmetry and the Effect of Disorder on the Mott-Hubbard Insulator (2001)
Denteneer, P. J. H., Scalettar, R. T., Trivedi, N.
Recent experiments have emphasized that our understanding of the interplay of electron correlations and randomness in solids is still incomplete. We address this important issue and demonstrate that...
Nature of the quantum phase transitions in the two-dimensional hardcore boson model (2001)
Hebert, F., Batrouni, G. G., Scalettar, R. T., Schmid, G., Troyer, M., Dorneich, A.
We use two Quantum Monte Carlo algorithms to map out the phase diagram of the two-dimensional hardcore boson Hubbard model with near ($V_1$) and next near ($V_2$) neighbor repulsion. At half filling...
Ab Initio Investigation of Collective Charge Excitations in MgB_2 (2001)
Ku, Wei, Pickett, W. E., Scalettar, R. T., Eguiluz, A. G.
A sharp collective charge excitation is predicted in MgB$_2$ at $\sim2.5eV$ for $q$ perpendicular to the boron layers, based on an all-electron analysis of the dynamical density response within...
Commensurate and Incommensurate Vortex Lattice Melting in Periodic Pinning Arrays (2001)
Reichhardt, C., Olson, C. J., Scalettar, R. T., Zimanyi, G. T.
We examine the melting of commensurate and incommensurate vortex lattices interacting with square pinning arrays through the use of numerical simulations. For weak pinning strength in the...
Individual and Multi Vortex Pinning in Systems with Periodic Pinning Arrays (2001)
Reichhardt, C., Zimanyi, G. T., Scalettar, R. T., Hoffmann, A., Schuller, Ivan K.
We examine multi and individual vortex pinning in thin superconductors with periodic pinning arrays. For multi-vortex pinning we observe peaks in the critical current of equal magnitude at every...
Enjalran, M., Hebert, F., Batrouni, G. G., Scalettar, R. T., Zhang, Shiwei
We study the effects of disorder on long-range antiferromagnetic correlations in the half-filled, two dimensional, repulsive Hubbard model at T=0. A mean field approach is first employed to gain a...
Disordering Transitions in Vortex Matter: Peak Effect and Phase Diagram (2000)
Olson, C. J., Reichhardt, C., Scalettar, R. T., Zimanyi, G. T., Gronbech-Jensen, N.
Using numerical simulations of magnetically interacting vortices in disordered layered superconductors we obtain the static vortex phase diagram as a function of magnetic field and temperature. For...
Paiva, Thereza, Scalettar, R. T., Huscroft, Carey, McMahan, A. K.
Local moment formation driven by the on--site repulsion $U$ is one of the most fundamental features in the Hubbard model. At the simplest level, the temperature dependence of the local moment is...
Metastability and Transient Effects in Vortex Matter Near a Disorder Driven Transition (2000)
Olson, C. J., Reichhardt, C., Scalettar, R. T., Zimanyi, G. T., Gronbech-Jensen, N.
We examine metastable and transient effects both above and below the first-order disorder driven decoupling line in a 3D simulation of magnetically interacting pancake vortices. We observe pronounced...
The Effect of Splayed Pins on Vortex Creep and Critical Currents (1999)
Olson, C. J., Scalettar, R. T., Zimanyi, G. T.
We study the effects of splayed columnar pins on the vortex motion using realistic London Langevin simulations. At low currents vortex creep is strongly suppressed, whereas the critical current j_c...
Phase separation in supersolids (1999)
Batrouni, G. G., Scalettar, R. T.
We study quantum phase transitions in the ground state of the two dimensional hard-core boson Hubbard Hamiltonian. Recent work on this and related models has suggested ``supersolid'' phases with...
Conducting phase in the two-dimensional disordered Hubbard model (1999)
Denteneer, P. J. H., Scalettar, R. T., Trivedi, N.
We study the temperature-dependent conductivity $\sigma(T)$ and spin susceptibility $\chi(T)$ of the two-dimensional disordered Hubbard model. Calculations of the current-current correlation function...
Auxiliary-field Monte Carlo for Quantum Spin and Boson Systems (1999)
We describe a new algorithm for the numerical simulation of quantum spin and boson systems. The method is based on the Trotter decomposition in imaginary time and a decoupling by auxiliary Ising...
Similarities between the Hubbard and Periodic Anderson Models at Finite Temperatures (1999)
Held, K., Huscroft, C., Scalettar, R. T., McMahan, A. K.
The single band Hubbard and the two band Periodic Anderson Hamiltonians have traditionally been applied to rather different physical problems - the Mott transition and itinerant magnetism, and Kondo...
Magnetic and Thermodynamic Properties of the Three-Dimensional Periodic Anderson Hamiltonian (1998)
Huscroft, Carey, McMahan, A. K., Scalettar, R. T.
The three dimensional periodic Anderson model is studied with Quantum Monte Carlo. We find that the cross-over to the Kondo singlet regime is remarkably sharp at low temperatures, and that the...
Quantum Monte Carlo Study of the Disordered Attractive Hubbard Model (1998)
Scalettar, R. T., Trivedi, N., Huscroft, C.
We investigate the disorder-driven superconductor to insulator quantum phase transition (SIT) in an interacting fermion model using determinantal quantum Monte Carlo (QMC) methods. The disordered...
Ordered states in the disordered Hubbard model (1998)
Denteneer, P. J. H., Ulmke, M., Scalettar, R. T., Zimanyi, G. T.
The Hubbard model is studied in which disorder is introduced by putting the on-site interaction to zero on a fraction f of (impurity) sites of a square lattice. Using Quantum Monte Carlo methods and...
Volume-Collapse Transitions in the Rare Earth Metals (1998)
McMahan, A. K., Huscroft, C., Scalettar, R. T., Pollock, E. L.
We describe current experimental and theoretical understanding of the pressure-induced volume collapse transitions occurring in the early trivalent rare earth metals. General features of orbitally...
Disorder and Impurities in Hubbard-Antiferromagnets (1998)
Ulmke, M., Denteneer, P. J. H., Janis, V., Scalettar, R. T., Singh, A., Vollhardt, D., ...
We study the influence of disorder and randomly distributed impurities on the properties of correlated antiferromagnets. To this end the Hubbard model with (i) random potentials, (ii) random hopping...
One particle spectral weight of the three dimensional single band Hubbard model (1996)
Ulmke, M., Scalettar, R. T., Nazarenko, A., Dagotto, E.
Dynamic properties of the three-dimensional single-band Hubbard model are studied using Quantum Monte Carlo combined with the maximum entropy technique. At half-filling, there is a clear gap in the...
Huscroft, C., Scalettar, R. T.
The half-filled attractive Hubbard model exhibits simultaneous charge density wave and superconducting order in its ground state. In this paper we explore the effect of disorder in the site energies...
Phase Diagram for Splay Glass Superconductivity (1995)
Devereaux, T. P., Scalettar, R. T., Zimanyi, G. T., Moon, K., Loh, E.
Localization of flux lines to splayed columnar pins is studied. A sine-Gordon type renormalization group study reveals the existence of a Splay glass phase and yields an analytic form for the...
Mean Field Theory of the Localization Transition (1995)
Pazmandi, F., Zimanyi, G. T., Scalettar, R. T.
A mean field theory of the localization transition for bosonic systems is developed. Localization is shown to be sensitive to the distribution of the random site energies. It occurs in the presence...
Simultaneous Diagonal and Off Diagonal Order in the Bose--Hubbard Hamiltonian (1994)
Scalettar, R. T., Batrouni, G. G., Kampf, A. P., Zimanyi, G. T.
The Bose-Hubbard model exhibits a rich phase diagram consisting both of insulating regimes where diagonal long range (solid) order dominates as well as conducting regimes where off diagonal long...
Vekic, M., Cannon, J. W., Scalapino, D. J., Scalettar, R. T., Sugar, R. L.
We study the two-dimensional periodic Anderson model at half-filling using quantum Monte Carlo (QMC) techniques. The ground state undergoes a magnetic order-disorder transition as a function of the...
Devereaux, T. P., Scalettar, R. T., Zimanyi, G. T.
The behavior of flux lines in the presence of both columnar and point disorder in 1+1 dimension is investigated using Renormalization Group and world-line Quantum Monte Carlo techniques. In...
Supersolids in the Bose-Hubbard Hamiltonian (1994)
Batrouni, G. G., Scalettar, R. T., Zimanyi, G. T., Kampf, A. P.
We use a combination of numeric and analytic techniques to determine the groun d state phase diagram of the Bose--Hubbard Hamiltonian with longer range repulsi ve interactions. At half filling one...
The Bose--Hubbard Model and Superfluid Staircases in $^{4}$He Films (1993)
Zimanyi, G. T., Crowell, P. A., Scalettar, R. T., Batrouni, G. G.
The recent experimental observation of step-like structure in the superfluid density of $^{4}$He films on graphite is interpreted in terms of passage close to Mott insulating lobes in the...
Universal Conductivity in the Two dimensional Boson Hubbard Model (1993)
Batrouni, G. G., Larson, B., Scalettar, R. T., Tobochnik, J., Wang, J.
We use Quantum Monte Carlo to evaluate the conductivity $\sigma$ of the 2--dimensional disordered boson Hubbard model at the superfluid-bose glass phase boundary. At the critical point for particle...