The Work-Hamiltonian Connection and the Usefulness of the Jarzynski Equality for Free Energy Calculations

The connection between work and changes in the Hamiltonian for a system with a time-dependent Hamiltonian has recently been called into question, casting doubt on the usefulness of the Jarzynski equality for calculating free energy changes. In this paper, we discuss the relationship between two possible definitions of free energy and show how some recent disagreements regarding the applicability of the Jarzynski equality are the result of different authors using different definitions of free energy. Finally, in light of the recently raised doubts, we explicitly demonstrate that it is indeed possible to obtain physically relevant free energy profiles from molecular pulling experiments by using the Jarzynski equality and the results of Hummer and Szabo.Comment: 3 page

Strange Hadrons from the ALCOR Rehadronization Model

Hadron multiplicities --- especially for strange particles --- are calculated in the framework of the algebraic coalescence rehadronization model (ALCOR), which counts for redistribution of quarks into hadrons for relativistic heavy-ion collisions. The influence of Bjorken flow on the final hadronic composition are incorporated in the model. A comparison is made with the CERN SPS NA35 $S+S$ and $p+p$ experiments. The analysis of these experiments with ALCOR shows a strangeness enhancement for S+S collisions and a possible formation of a sort of semi-deconfined state of the matter. Predictions for Pb+Pb collisions (NA49) are also presented.Comment: 14 pages, LaTeX, Review to appear in Proceedings of Strangeness'95, Tucson, Arizona, Jan. 4--6 1995. (American Institute of Physics

Faces of quark matter

Based on an analysis in the framework of a coalescence hadronization model (ALCOR) we conclude that in heavy ion collisions at CERN SPS and RHIC energies a new type of matter, the massive quark-antiquark matter is produced.Comment: Talk given at Budapest Workshop on Quark and Hadron Dynamics in Relativistic Heavy Ion Collisions (BP 2002) Budapest, Hungary, 3-7 Mar 2002. 12 pages in Latex, 8 PS figure. Submitted to Heavy Ion Physics. Note added in proo

Suppression of p-Wave Baryons in Quark Recombination

We show that the observed suppression of the $\Lambda(1520)/\Lambda$ ratio in central Au + Au collisions at the Relativistic Heavy Ion Collider can be naturally understood in the constituent quark recombination model.Comment: 3 pages, 1 figur