Covariant description of kinetic freeze-out through a finite spacelike layer

The problem of freeze-out (FO) in relativistic heavy-ion reactions is addressed. We develop and analyze an idealized one-dimensional model of FO in a finite layer, based on the covariant FO probability. The resulting post FO phase-space distributions are discussed for different FO probabilities and layer thicknesses.

Escape over a potential barrier driven by colored noise: Large but finite correlation times

The recent theory of Tsironis and Grigolini for the mean first-passage time from one metastable state to another of a bistable potential for long correlation times of the noise is extended to large but finite correlation times.

Equation of state of hot, dense stellar matter. Finite temperature nuclear Thomas-Fermi approach

The properties of hot, dense stellar matter are investigated with a finite temperature nuclear Thomas-Fermi model.

Comment on "Influence of bulk properties on the surface structure of finite nuclei"

We comment on a recent paper by Uma Maheswari et al. in which it is claimed that quantal calculations of the half-infinite nuclear matter, in contrast to semiclassical approximations, exhibit an unusually strong dependence of the 90%10% surface thickness of the density profile on the Fermi momentum kF at saturation. This conclusion was carried over to the surface incompressibility. On the contrary we find essential agreement between semiclassical and quantal results and very weak dependence on kF of the quantities in question.

Finite-temperature QED effects in atoms

We argue that low-temperature effects in QED can, if anywhere, only be quantitatively interesting for bound electrons. Unluckily the dominant thermal contribution turns out to be level independent, so that it does not affect the frequency of the transition radiation.

BRST-invariant path integral for a spinning relativistic particle

The propagator of a relativistic spinning particle is calculated using the Becchi-Rouet-Stora-Tyutin-(BRST)-invariant path-integral formalism of Fradkin and Vilkovisky. The spinless case is considered as an introduction to the formalism.

Pseudoclassical description for a nonrelativistic spinning particle II. Classical content

The pure classical content of a pseudoclassical nonrelativistic model of a spinning particle is studied. The only physical meaningful world line is the one without "Zitterbewegung." Interactions with external electromagnetic fields are also studied.

Pseudoclassical description for a nonrelativistic spinning particle. I. The Levy-Leblond equation

A pseudoclassical model for a spinning nonrelativistic particle is presented. The model contains two first-class constraints which after quantization give rise to the Levy-Leblond equation for a spin-1/2 particle.

Pseudoclassical description of a relativistic spinning particle

A pseudoclassical model for a relativistic spinning particle is studied. The only physically meaningful world line is the one without Zitterbewegung. The Poincar realization for this situation is constructed.

Nonrelativistic bound states at finite temperature. II. Muonic hydrogen

We illustrate how to apply modern effective field-theory techniques and dimensional regularization to factorize the various scales, which appear in QED bound states at finite temperature. We focus here on the muonic hydrogen atom. Vacuum polarization effects make the physics of this atom at finite temperature very close to that of heavy quarkonium states. We comment on the implications of our results for these states in the quark gluon plasma. In particular, we estimate the effects of a finite-charm quark mass in the dissociation temperature of bottomonium.