Toshiki Maruyama -- Structured Mixed Phase of Nuclear Matter

The phase transitions in nuclear matter include: Liquid-gas, neutron drip, meson condensation, hyperon mixture, quark deconfinement, color super-conductivity, and others. Some of these are first order transitions, which means that near the transition, there will be mixed phases. This makes studying the dense matter equation of state (EOS) and thermodynamic properties of mixed phases interesting. This harkens back to "nuclear pasta", as proposed by Ravenhall et al (1983). and Hashimoto et al (1984, in PTP 71 320).

This has modest implications for the structure of neutron stars, but more importantly, it has strong implications for supernovae. These structures of mixed phases occur at below nuclear saturation density, and so are going to be important in determining how supernovae explosions proceed.

At present, many researches who use the EOS, or perform calculations of EOS properties, do so without considering the effects of pasta structure; what Toshiki underlined is, these structures are sometimes is important, and should not be neglected. More importantly, he presented the result that including coulomb screening in the calculations of pressure as a function of density makes the more complex bulk Gibbs calculation have a result which is more similar to the Maxwell construction in the region of the phase transition (which is the result of a more simple calculation).