Related papers: Structural Instability in Polyacene : A Projector …
There exist two types of structural instability in polyacene: double bonds in a cis pattern and those in a trans pattern. They are isoenergetic but spectroscopically distinct. We demonstrate optical characterization and manipulation of…
We develop a new $\it {symmetrized}$ version of the Projector Quantum Monte Carlo (SPQMC) method which preserves the symmetries of the system by simultaneously sampling all symmetry related Ising configurations at each MC step and use it to…
Motivated by recent experiments realizing correlated phenomena and superconductivity in 2D van der Waals devices, we consider the general problem of whether correlation effects may be enhanced by modifying band structure while keeping a…
With the recently emerging global interest in building a next generation of circular electron-positron colliders to study the properties of the Higgs boson, and other important topics in particle physics at ultra-high beam energies, it is…
We have studied the spin-polarized three-dimensional homogeneous electron gas using the diffusion quantum Monte Carlo method, with trial wave functions including backflow and three-body correlations in the Jastrow factor, and we have used…
In this article, we report a fully ab initio variational Monte Carlo study of the linear, and periodic chain of Hydrogen atoms, a prototype system providing the simplest example of strong electronic correlation in low dimensions. In…
The $C_{60}$ molecule and its fragments are studied using Configuration Interaction (CI) and Variational Monte Carlo (VMC) techniques, within the Hubbard model. Using benzene as a test case, we compare the results of the approximate…
Distortions in a family of conjugated polymers are studied within two complementary approaches, i.e. within a many-body Valence Bond (VB) approach using a transfer matrix technique to treat the Heisenberg model of the systems, and also in…
Motivated by the growing interest in accessing the spin structure of multi-boson processes and in measuring quantum entanglement at high energies, we study polarisation and spin-correlation coefficients in di-boson systems. We show that…
By applying the projection technique to the computation of excitation energies, we study the correlation effects on the band gap of conducting polymers. In the presence of an additional electron or hole, the correlation induces a…
The effect of correlation on Peierls transition, which is accompanied by a dimerization, t_d, of a bond alternation for transfer energy, has been examined for a half-filled one-dimensional electron system with on-site repulsive interaction…
An interacting pair of polyacetylene chains are initially modeled as a couple of undimerized polymers described by a Hamiltonian based on the tight-binding model representing the electronic behavior along the linear chain, plus a Dirac's…
Results of a phenomenological Monte carlo calculation for a 2D electron-phonon Holstein model near a Peierls-CDW transition are presented. Here the zero Matsubara frequency part of the phonon action is dominant and we approximated it by a…
We employ a large-scale, unbiased constrained-path quantum Monte Carlo method to systematically simulate the effective two-orbital Hubbard model for twisted bilayer graphene in order to gain deeper insight into the relationship between…
Quantum Monte Carlo method is used to look into the superconductivity in the three-leg Hubbard ladder. The enhanced correlation for the pairing across the central and edge chains, which has been predicted in the weak-coupling…
Electronic structure and dielectric property in an electronic ferroelectricty, where electric polarization is driven by an electronic charge order without inversion symmetry, are studied. Motivated from layered iron oxides, roles of quantum…
We present recent theoretical results on superconductivity in correlated-electron systems, especially in the two-dimensional Hubbard model and the three-band d-p model. The mechanism of superconductivity in high-temperature superconductors…
A systematic method to account for electron correlation in periodic systems which can predict quantitatively correct band structures of non-conducting solids from first principles is presented. Using localized Hartree-Fock orbitals (both…
We consider an electron-phonon system in two and three dimensions on square, hexagonal and cubic lattices. The model is a modification of the standard Holstein model where the optical branch is appropriately curved in order to have a…
We use continuous-time quantum Monte Carlo simulations to study retardation effects in the metallic, quarter-filled Holstein model in one dimension. Based on results which include the one- and two-particle spectral functions as well as the…