The Abdus Salam International Centre for Theoretical Physics Phase Transitions for Quantum Xy -model on the Cayley Tree of Order Three in Quantum Markov Chain Scheme

High order perturbation study of the frustrated quantum Ising chain

In this paper, using high order perturbative series expansion method, the critical exponents of the order parameter and susceptibility in transition from ferromagnetic to disordered phases for 1D quantum Ising model in transverse field, with ferromagnetic nearest neighbor and anti-ferromagnetic next to nearest neighbor interactions, are calculated. It is found that for small value of the frustr...

IC/98/220 United Nations Educational Scientific and Cultural Organization and International Atomic Energy Agency THE ABDUS SALAM INTERNATIONAL CENTRE FOR THEORETICAL PHYSICS THE KINETIC SPIN-1 BLUME-CAPEL MODEL WITH COMPETING DYNAMICS

We have studied by means of Monte-Carlo simulation and exact finite-size analysis, the spin-1 Blume Capel model with Glauber and Kawasaki dynamics. The Kawasaki spin exchange process flows energy into the system from an external source. Some phase diagrams of the model are presented. For some values of the parameters, the system displays a kind of self organization phenomenon within the disorde...

United Nations Educational Scientific and Cultural Organization and International Atomic Energy Agency THE ABDUS SALAM INTERNATIONAL CENTRE FOR THEORETICAL PHYSICS THE GENERALIZED MODEL OF POLYPEPTIDE CHAIN DESCRIBING THE HELIX-COIL TRANSITION IN BIOPOLYMERS

United Nations Educational Scientific and Cultural Organization and International Atomic Energy Agency THE ABDUS SALAM INTERNATIONAL CENTRE FOR THEORETICAL PHYSICS SELF-CONSISTENT NONLINEARLY POLARIZABLE SHELL-MODEL DYNAMICS FOR FERROELECTRIC MATERIALS

We investigate the dynamical properties of the polarizable shell-model with a symmetric double Morse-type electron-ion interaction in one ionic species. A variational calculation based on the Self-Consistent Einstein Model (SCEM) shows that a theoretical ferroelectric (FE) transition temperature can be derived which demonstrates the presence of a first-order phase transition for the potassium s...

Energy states and exchange energy of coupled double quantum dot in a magnetic field

The ground state energies of two interacting electrons confined in a coupled double quantum dot (DQD) presented in a magnetic field has been calculated by solving the relative Hamiltonian using variational and exact diagonalization methods. The singlet-triplet transitions in the angular momentum and spin of the quantum dot ground state had been shown .We have studied the magnetic field versus c...