Usually, the relaxation times of a gas are estimated in the frame of the Boltzmann equation. In this paper, instead, we deal with the relaxation problem in the frame of the dynamical theory of Hamiltonian systems, in which the definition itself of a relaxation time is an open question. We introduce a lower bound for the relaxation time, and give a general theorem for estimating it. Then we give...

%e have measured the ac magnetic susceptibility of the model dilute dipolar-coupled Ising system LiHo„Y& -„F4. The x 0.46 material displays an ordinary ferromagnetic transition, while the x 0.045 and 0.167 samples are two very different magnetic glasses. Thermal relaxation times are more than five times longer for x 0.167 than for x ~0.045. In addition, the more concentrated glass shows history...

The present investigation is concerned with the propagation of waves at an imperfect boundary of heat conducting elastic solid and micropolar fluid media. The amplitude ratios of various reflected and transmitted waves are obtained in a closed form due to incidence of longitudinal wave (P-wave), thermal wave (T-wave), and transverse wave (SV-wave). The variation of various amplitude ratios with...

Using renormalization group methods we evaluate the thermal strangeness and charm chemical equilibrium relaxation times in the deconfined quark-gluon plasma. We present a reaction model and evaluate the total production rate of strangeness in fixed target Pb–Pb collisions at 10–300 A GeV. We discuss the relevance of our results to the diagnosis and understanding of the properties of the deconfi...

The thermal magnetoresistance, optical magnetoreflectance, and extremal properties of the energy loss spectrum connected with the cyclotron resonance effect are approached on a theoretical basis. The formalism, which applies the idea of two kinds of relaxation times active for the electron magnetotransport in a metal, gives – at least qualitatively – a satisfactory agreement with the observed d...

The novel photoswitchable bis-azo derivative reported herein shows a high temporal resolution of 2 × 10(8) times between the thermal relaxation rates of its two constituting photochromes. Moreover, the slow and fast azo building blocks of this molecular construct can be triggered by using UV and visible light, respectively.

We set up a framework for field theoretical studies of systems out of thermal equilibrium and zoom in on the dissipation of disoriented chiral condensates. Short relaxation times are obtained in the phase transition region, jeopardizing the definiteness of a DCC signal.

In the context of the Müller-Israel-Stewart second order phenomeno-logical theory for dissipative fluids, we analyze the effects of thermal conduction and viscosity in a relativistic fluid, just after its departure from hydrostatic equilibrium, on a time scale of the order of relaxation times. Stability and causality conditions are contrasted with conditions for which the " effective inertial m...

Push-pull bithienylpyrrole-based azo dyes exhibit thermal isomerisation rates as fast as 1.4 μs in acetonitrile at 298 K becoming, thus, the fastest neutral azo dyes reported so far. These remarkably low relaxation times can be transferred into liquid-crystalline matrices enabling light-triggered oscillations in the optical density of the final material up to 11 kHz under ambient conditions.

In this paper, we study the thermal relaxation in the one-dimensional self-gravitating system, or the so-called sheet model. According to the standard argument, the thermal relaxation time of the system is around Nt c , where N is the number of sheets and t c is the crossing time. It has been claimed that the system does not reach the thermal equilibrium in this thermal relaxation timescale, an...