Location: Cyclotron Building (434), Seminar Room
Dr. Gerd Röpke, University of Rostock, Germany
Low-Density Nuclear Matter Equation of State and Symmetry Energy:
Cluster Formation and Condensates
Abstract:
The equation of state (EoS) of nuclear matter at finite temperature and density with various proton fractions is considered, in particular the region of medium excitation energy given by the temperature range T ≤ 30 MeV and the baryon density range ρB ≤ 1014.2 g/cm3. Standard approaches such as Dirac Brueckner Hartree Fock (DBHF) or Relativistic Mean Field (RMF) are not applicable in that region. In addition to the mean-field effects, the formation of few-body correlations, in particular light bound clusters up to the α-particle (1 ≤ A ≤ 4) have to be taken into account. The calculation is based on a many-particle approach, the medium modification of the light clusters is described by self-energy and Pauli blocking effects. The Mott effect is discussed describing the dissolution of light clusters with increasing density. Evaluating the chemical potential and related thermodynamic quantities for different temperatures and densities as function of the asymmetry parameter, the symmetry energy is determined. Comparison is made with different theoretical approaches as well as with recent experimental analysis of moderate-temperature nuclear gases produced in violent heavy-ion collisions. Benchmarks such as virial expansion in the low-density limit or low-temperature limit are considered. The resulting thermodynamic properties are of relevance for heavy-ion collisions and astrophysical applications such as supernova simulations.