M. Elahi | Searcharxiv

arXiv2020

Thermodynamics and and phase transition of topological dilatonic Lifshitz-like black holes

It is known that scalar-tensor gravity models can be studied in Einstein and Jordan frames. In this paper, we consider a model of scalar-tensor gravity in Einstein's frame to calculate the Lifshitz-like black hole solutions with different horizon topologies. We study thermodynamic properties and first order van der Waals like phase transition, and find that the Lifshitz parameter affects the phase structure. In addition, we investigate thermal stability by using the behavior of heat capacity and various methods of geometrical thermodynamics.

gr-qc↗

arXiv2015

Investigation of frustrated and dimerized classical Heisenberg chains

We have considered the 1D dimerized frustrated antiferromagnetic (ferromagnetic) Heisenberg model with arbitrary spin $S$. The exact classical magnetic phase diagram at zero temperature is determined using the LK cluster method. Cluster method results, show that the classical ground state phase diagram of the model is very rich including first and second-order phase transitions. In the absence of the dimerization, a second-order phase transition occurs between antiferromagnetic (ferromagnetic) and spiral phases at the critical frustration $α_c=\pm 0.25$. In the vicinity of the critical points $α_c$, the exact classical critical exponent of the spiral order parameter is found 1/2. In the case of dimerized chain ($δ\neq0$), the spiral order shows stability and exists in some part of the ground state phase diagram. We have found two first-order critical lines in the ground state phase diagram. These critical lines separate the antiferromagnetic from spiral phase.

cond-mat.str-el↗