The temperature-dependent phase diagrams of the spin-3/2 Ising model on a two-layer Bethe lattice with ferromagnetic (FM)/antiferromagnetic (AFM) intra-layer and either FM or AFM type inter-layer interactions are investigated under a constant magnetic field (H) and in the presence of a crystal...

The phase transitions of a diluted spin-12 Ising film are examined using the framework of the effective field theory with a probability distribution technique that accounts for the single-site spin correlations. The critical temperature Tc/J of the system is calculated as a function of the...

A one-dimensional model having a unique ground state and admitting a phase transition is constructed.

We present a statistical mechanics description to study the ground state of quantum systems. In this approach, averages for the complete system are calculated over the non-interacting energy levels. Taking a different interaction parameter, the particles of the system fall into non-interacting...

We consider a stochastic model of N evolving particles studied by Brunet and Derrida. This model can be seen as a directed polymer in random medium with N sites in the transverse direction. Cook and Derrida use heuristic arguments to obtain a formula for the ground state energy of the polymer....

The structural, elastic and electronic properties of chalcopyrite compound CuInSe2 and CuGaSe2 have been investigated using the full-potential linearized muffin-tin orbital method (FP-LMTO) within the frame of density functional theory (DFT). In this approach, the local density approximation is...

I recently proposed a method of bosonization based on the use of coherent states of fermion composites, whose validity was restricted to smooth structure functions. In the present paper I remove this limitation and derive results which hold for arbitrary interactions and structure functions. The...

A constructive approach is presented to study the ferromagnetism in multi-band Hubbard models whose Hamiltonians consist of an electron hopping and an on-site Coulomb interaction. We prove that the models have the fully ferromagnetized ground states if the strength of the on-site Coulomb...

We consider the one-dimensional ferromagnetic Ising model with very long-range interaction under a periodic, biased and weak external field and prove that at sufficiently low temperatures the model has a unique limiting Gibbs state.

We investigate ground-state properties of antiferromagnetic thin films of the XY model under an external magnetic field and a uniaxial potential by numerical calculations. We clarify surface effects by comparing the ground-state properties of thin films with those of the system with infinite...