Ideal gas provides q-entropy

A mathematical procedure is suggested to obtain deformed entropy formulas of type K(S_K) = sum_i P_i K(-ln P_i), by requiring zero mutual K(S_K)-information between a finite subsystem and a finite reservoir. The use of this method is first demonstrated on the ideal gas equation of state with finite constant heat capacity, C, where it delivers the Renyi and Tsallis formulas. A novel interpretation of the qstar = 2-q duality arises from the comparison of canonical subsystem and total microcanonical partition approaches. Finally a new, generalized deformed entropy formula is constructed for the linear relation C(S) = C_0 + C_1 S.Comment: more introduction, citations and derivation in v3; accepted in Physica

Strange Quark Matter Theory

Theoretical approaches to strange and other types of quark matter accounted for at the SQM2003 Meeting are reviewed. They range from simple statistical models through perturbative QCD supported mico-dynamical simulations til lattice gauge theory and astrophysics results. Finally some ideas for future research in this field are outlined.Comment: Theory summary talk given at Strange Quark Matter 2003 Conference, March 12-17, 2003, Atlantic Beach, NC, USA. (LateX 19 pages, 15 postscript figures.