Unruh Entropy of a Schwarzschild Black Hole

The entropy produced by Unruh radiation is estimated and compared to the entropy of a Schwarzschild black hole. We simulate a spherical system of mass M by a set of Unruh horizons and estimate the total entropy of the outgoing radiation. Dependence on the mass and spin of the emitted particles is taken into account. The obtained results can be easily extended to any other intrinsic degrees of freedom of outgoing particles. The ratio of Unruh entropy to the Schwarzschild black hole entropy is derived in exact analytical form. For large black holes, this ratio exhibits high susceptibility to quantum numbers, e.g., spin s, of emitted quanta and varies from 0% for s=0 to 19.0% for s=5/2

Unruh Effect and Information Entropy Approach

The Unruh effect can be considered a source of particle production. The idea has been widely employed in order to explain multiparticle production in hadronic and heavy-ion collisions at ultrarelativistic energies. The attractive feature of the application of the Unruh effect as a possible mechanism of the multiparticle production is the thermalized spectra of newly produced particles. In the present paper, the total entropy generated by the Unruh effect is calculated within the framework of information theory. In contrast to previous studies, here the calculations are conducted for the finite time of existence of the non-inertial reference frame. In this case, only a finite number of particles are produced. The dependence on the mass of the emitted particles is taken into account. Analytic expression for the entropy of radiated boson and fermion spectra is derived. We study also its asymptotics corresponding to low- and high-acceleration limiting cases. The obtained results can be further generalized to other intrinsic degrees of freedom of the emitted particles, such as spin and electric charge

Total and Partial Shear Viscosity in Heavy-Ion Collisions at Energies of BES, FAIR and NICA

We calculated the shear viscosity of hot and dense nuclear matter produced in a symmetric system of central gold–gold collisions at energies of BES RHIC, FAIR and NICA. For calculations of the collisions, the transport model UrQMD was employed. The shear viscosity was obtained within the Green–Kubo formalism. The hadron resonance gas model was used to determine temperature and chemical potentials of baryon charge and strangeness out of microscopic model calculations. In contrast to our previous works, we determined the partial viscosity of the main hadron species, such as nucleons, pions, kaons and Lambdas, via the nucleon–nucleon, pion–pion and so forth, correlators. A decrease in the beam energy from Elab=40 to 10 AGeV leads a to rise in baryon shear viscosity accompanied by a drop in the shear viscosity of mesons. The ratio of total shear viscosity to entropy density also decreases

Unruh effect in heavy ion collisions

We apply the idea of the Unruh effect to the description of particle production in relativistic heavy ion collisions. Because the full information about all particles is needed, we employ the spectra of hadrons generated by the UrQMD model for pp and Au+Au collisions at various energies. Particles are considered as generated straight at the Unruh horizon thus allowing estimation of the Unruh temperature of the source. The analysis is provided for different types of mesons and their charges

Unruh effect in heavy ion collisions

We apply the idea of the Unruh effect to the description of particle production in relativistic heavy ion collisions. Because the full information about all particles is needed, we employ the spectra of hadrons generated by the UrQMD model for pp and Au+Au collisions at various energies. Particles are considered as generated straight at the Unruh horizon thus allowing estimation of the Unruh temperature of the source. The analysis is provided for different types of mesons and their charges

Calculation of shear viscosity in Au+Au collisions at NICA energies

Shear viscosity of hot and dense nuclear matter, produced in the central zone of central gold-gold collisions at energies of NICA, is calculated within the UrQMD model. Besides the microscopic simulations of heavy ion collisions, the procedure assumes the application of statistical model to determine the temperature and chemical potentials in the system, and study of the relaxation process within the UrQMD box with periodic boundary conditions. The latter is used for calculation of the correlator which enters the Green-Kubo formula for shear viscosity. The fluctuations at early and late stages of the system evolution are studied. Results are compared to predictions of other models