Related papers: Dimerization process and elementary excitations in…
We present analytical results for the strongly anisotropic random field Ising model, consisting of weakly interacting spin chains. We combine the mean-field treatment of interchain interactions with an analytical calculation of the average…
We make extensive simulations over a spin chain model that combines the frustrated $J_1\textrm{-}J_2$ spin chain and the long-range nonfrustrated $(-1)^{(r-1)}r^{-\alpha}$ decay interactions through the variational matrix product state…
A hybrid spin-electron system defined on one-dimensional double-tetrahedral chain, in which the localized Ising spin regularly alternates with two mobile electrons delocalized over a triangular plaquette, is exactly solved with the help of…
The confinement of elementary excitations induces distinctive features in the non-equilibrium quench dynamics. One of the most remarkable is the suppression of entanglement entropy which in several instances turns out to oscillate rather…
In order to study the effect of interaction and lattice distortion on quantum coherence in one-dimensional Fermi systems, we calculate the ground state energy and the phase sensitivity of a ring of interacting spinless fermions on a…
Dimerized valence bond solids appear naturally in spin-1/2 systems on bipartite lattices, with the geometric frustrations playing a key role both in their stability and the eventual `melting' due to quantum fluctuations. Here, we ask the…
The magnetic properties and electronic structure of the ground and excited states of two recently characterized endohedral metallo-fullerenes, [Gd$_2$@C$_{78}$]$^{-}$ (1) and [Gd$_2$@C$_{80}$]$^{-}$ (2), have been studied by theoretical…
A linear spin wave analysis of dimerization of alternating Heisenberg system with spins $s_{1}$ and $s_{2}$ on linear chain as well as square lattice is presented. Among the several possible dimerized configurations considered in two…
The spin-$1/2$ chain with antiferromagnetic exchange $J_1$ and $J_2 = \alpha J_1$ between first and second neighbors, respectively, has both gapless and gapped ($\Delta(\alpha) > 0$) quantum phases at frustration $0 \le \alpha \le 3/4$. The…
An imposed chemical potential gradient $A_\uparrow=d\mu_\uparrow/dx$ on a single fermionic species ("spin up") directly produces a gradient in the density $d\rho_\uparrow/dx$ across a lattice. We study here the induced density inhomogeneity…
A composite multiferroic chain with an interfacial linear magneto-electric coupling is used to study the magnetic and electric responses to an external magnetic or electric field. The simulation uses continuous spin dynamics through the…
We discuss the consequences of including both electron-phonon and electron-electron couplings in multi-band models, focusing on numerical studies of a one-dimensional two-band model in the intermediate regime for both coupling strengths.…
The properties of the ground state of one of the simplest models of frustrated magnetic systems, a dilute Ising chain in a magnetic field, are considered for all values of the concentration of charged non-magnetic impurities. An analytical…
Dynamic spin correlation function of the $S=1/2$ antiferromagnetic spin chain with alternating nearest neighbor and competing next nearest neighbor interactions is studied using the numerical diagonalization method. We find characteristics…
We study ground-state properties of the Heisenberg frustrated spin chain with interactions up to fourth nearest neighbors by the exact-diagonalization method and the density matrix renormalization group method. We find that ferrimagnetism…
We study the dimerized spin ladder with nearest-neighbor ($J_1$) and next-nearest-neighbor ($J_2$) anti-ferromagnetic interaction under a magnetic field. We predict the existence of different magnetization plateaus for the presence of…
We study the phase diagram, ground state properties, and excitation gaps of a frustrated spin-Peierls chain, i.e. a spin-Peierls chain with both nearest neighbor exchange $J_1$ and next nearest neighbor exchange $J_2$. The phase diagram is…
The elementary excitation spectrum of the spin-$\frac{1}{2}$ antiferromagnetic (AFM) Heisenberg chain is described in terms of a pair of freely propagating spinons. In the case of the Ising-like Heisenberg Hamiltonian spinons can be…
Three-coupled chains of quarter-filled Hubbard model with dimerization have been studied for periodic boundary conditions. By use of a renormalization group method, it is found that the interchain hopping is renormalized to zero leading to…
A model of disordered spin-Peierls system is considered, where domain walls are randomly distributed as a telegraph noise. For this realization of the disorder in an XX spin chain, we calculate exactly the density of states as well as…