Quantum Ising chain with boundary dephasing

We study the quantum Ising chain with boundary dephasing. By doubling the Hilbert space, the model is mapped to the Su–Schrieffer–Heeger model with imaginary chemical potential at the edges. We show analytically and numerically that the Liouvillian gap, i.e. the inverse relaxation time of the model, scales with the system size $ N $ as $ N^{-3} $.

Analysis of the integrated intensity of the central peaks calculated as a function of temperature in the ferroelectric phase of lithium tantalate

The integrated intensity of the central peak is calculated as a function of temperature in the ferroelectric phase (T < TC) of nearly stoichiometric LiTaO3. This calculation is performed using the temperature dependence of the order parameter obtained from the mean field theory at temperatures lower than the transition temperature TC (TC = 963 K) of this crystal. The calculated values of the order parameter (squared) are fitted to the integrated intensity of the central peaks as observed from the Raman and Brillouin scattering experiments as reported in the literature in the ferroelectric phase of nearly stoichiometric LiTaO3. Our results are in good agreement with the observed behavior of LiTaO3 crystal. Because of the applications of LiTaO3 in several academic disciplines including the material science and thermal science, it is beneficial to investigate dynamic properties of this crystal such as the damping constant, inverse relaxation time and the activation energy as also we studied here.

Universal Constraints on Relaxation Times for d-Level GKLS Master Equations

In 1976, Gorini, Kossakowski, Sudarshan and Lindblad independently discovered a general form of master equations for an open quantum Markovian dynamics. In honor of all the authors, the equation is nowadays called the GKLS master equation. In this paper, we show universal constraints on the relaxation times valid for any d-level GKLS master equations, which is a generalization of the well-known constraints for 2-level systems. Specifically, we show that any relaxation rate, the inverse-relaxation time, is not greater than half of the sum of all relaxation rates. Since the relaxation times are measurable in experiments, our constraints provide a direct experimental test for the validity of the GKLS master equations, and hence for the conditions of the complete positivity and Markovianity.

Dielectric relaxation studies of binary mixture of β-picoline and methanol using time domain reflectometry at different temperatures

Complex permittivity spectra of binary mixtures of varying concentrations of [Formula: see text]-picoline and Methanol (MeOH) have been obtained using time domain reflectometry (TDR) technique over frequency range 10 MHz to 25 GHz at 283.15, 288.15, 293.15 and 298.15 K temperatures. The dielectric relaxation parameters namely static permittivity ([Formula: see text]), high frequency limit permittivity ([Formula: see text]) and the relaxation time ([Formula: see text]) were determined by fitting complex permittivity data to the single Debye/Cole-Davidson model. Complex nonlinear least square (CNLS) fitting procedure was carried out using LEVMW software. The excess permittivity ([Formula: see text]) and the excess inverse relaxation time (1/[Formula: see text] which contain information regarding molecular structure and interaction between polar–polar liquids were also determined. From the experimental data, parameters such as effective Kirkwood correlation factor (geff), Bruggeman factor (fB) and some thermo dynamical parameters have been calculated. Excess parameters were fitted to the Redlich–Kister polynomial equation. The values of static permittivity and relaxation time increase nonlinearly with increase in the mol–fraction of MeOH at all temperatures. The values of excess static permittivity ([Formula: see text]E) and the excess inverse relaxation time (1/[Formula: see text] are negative for the studied [Formula: see text]-picoline — MeOH system at all temperatures.

Dielectric, Thermodynamic, and Computational Studies of Hydrogen Bonded Binary Mixtures of N-Methylaniline with Propan-1-ol and Isopropyl Alcohol

The molecular interactions between the polar systems N-methylaniline with alcohols, propan-1-ol, and isopropyl alcohol for various mole fractions at different temperatures are studied by determining the dielectric permittivity using LF impedance analyzer, microwave bench, and Abbe's refractometer in radio, microwave, and optic frequency regions, respectively. Dipole moment, excess dipole moment, excess Helmholtz free energy, excess permittivity, excess inverse relaxation time, and excess thermodynamical values are calculated using experimental data. Hamiltonian quantum mechanical calculations are performed using PC Spartan and ArgusLab modeling softwares for both pure and equimolar binary systems of N-methyl aniline with alcohols.

Influence of an upper-hybrid pump on temperature relaxation processes in a magnetized plasma

By means of kinetic fluctuation theory, the relaxation process between the electron and ion temperatures in a magnetized homogeneous plasma is considered. The cases when the external upper-hybrid pump wave excites modified convective cells and ion-acoustic waves are analysed. The inverse relaxation time in the regime where the turbulent fluctuations are developed is calculated for these cases and its dependence on the pump wave and plasma parameters is deduced.

Dielectric relaxation of butyl acrylate—alcohol mixtures using time domain reflectometry

Dielectric relaxation measurements of butyl acrylate—alcohol mixtures at different concentrations and temperatures within the frequency range of 10 MHz to 10 GHz have been carried out using time domain reflectometry. Parameters such as the static permittivity, dielectric relaxation time, the Kirkwood correlation factor, the excess inverse relaxation time, and thermodynamic functions were determined and discussed to yield information on the molecular structure and dynamics of the mixture. The value of the dielectric properties decreases with increasing butyl acrylate concentration in alcohol and systematically varies with the length of alcohol alkyl chain. Negative values of the excess inverse relaxation time found for all concentrations and at all temperatures studied may indicate that the effective dipoles rotate slowly.