Sharif Digital Repository

Correlations disguised in various forms underlie a host of important phenomena in classical and quantum systems, such as information and energy exchanges. The quantum mutual information and the norm of the correlation matrix are both considered as proper measures of total correlations. We demonstrate that, when applied to the same system, these two measures can actually show significantly different behavior except at least in two limiting cases: when there are no correlations and when there is maximal quantum entanglement. We further quantify the discrepancy by providing analytic formulas for time derivatives of the measures for an interacting bipartite system evolving unitarily. We argue... 

The present paper addresses an analytical method to determine the electroelastic fields over a double-phase piezoelectric reinforcement interacting with an ellipsoidal single-inhomogeneity. The approach is based on the extension of the electro-mechanical equivalent inclusion method (EMEIM) to the piezoelectric double-inhomogeneity system. Accordingly, the double-inhomogeneity is replaced by an electroelastic double-inclusion problem with proper polynomial eigenstrains-electric fields. The long- and short-range interaction effects are intrinsically incorporated by the homogenizing eigenfields. The equivalent double-inclusion is subsequently decomposed to the single-inclusion problems by means... 

The particle-hole continuum (PHC) for massive Dirac fermions provides an unprecedented opportunity for the formation of two collective split-off states, one in the singlet and the other in the triplet (spin-1) channel, when the short-range interactions are added to the undoped system. Both states are close in energy and are separated from the continuum of free particle-hole excitations by an energy scale of the order of the gap parameter Δ. They both disperse linearly with two different velocities, reminiscent of spin-charge separation in Luttinger liquids. When the strength of Hubbard interactions is stronger than a critical value, the velocity of singlet excitation, which we interpret as a... 

The particlehole continuum in the Dirac sea of graphene has a unique window underneath, which in principle leaves room for bound state formation in the triplet particlehole channel (Baskaran and Jafari 2002 Phys. Rev. Lett. 89 016402). In this work, we construct appropriate triplet particlehole operators and, using a repulsive Hubbard-type effective interaction, we employ equations of motion to derive approximate eigenvalue equations for such triplet operators. While the secular equation for the spin density fluctuations gives rise to an equation which is second order in the strength of the short range interaction, the explicit construction of the triplet operators obtained here shows that,... 

Saturation molality of sodium chloride in mixed aqueous electrolyte solutions containing NaCl, CaSO4 and Na2SO4 was measured at atmospheric pressure over the wide range of temperatures using an equilibrium cell equipped with an accurate temperature control system. The measurements were carried out at different CaSO4 and Na2SO4 concentrations. In order to check the repeatability of the experimental data for the saturation molality of NaCl, the experiments were replicated three times and the values reported were the average of the replicas. To model the data generated in this work, the PDH+UNIFAC-Dortmund activity coefficient model was used. The model used to predict the mean ionic activity... 

Equations of state based on the statistical associating fluid theory for potentials of variable range (SAFT-VR) and the perturbed chain statistical associating fluid theory (PC-SAFT) have been used to model the PVT behavior of ionic liquids and the solubility of H2S in six imidazolium-based ionic liquids. The studied systems included [bmim][PF6], [hmim][PF6], [bmim][BF4], [hmim][BF4], [bmim][NTF2] and [hmim][NTF2] at various temperatures and pressures.For pure components, parameters of the models have been obtained by fitting the models to experimental data on liquid densities; the average relative deviation between the calculated and experimental densities for ionic liquids is less than...