Kaon condensation and Neutron stars

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1.Proper ties of hot neutron stars just born after supernova explosions by the use of a realistic nuclear forceWe studied the properties of hot neutron stars and calculated the energy release and spin-up ratio during their evolution.2.Kaon condensation at finite temperature and protoneutron starsWe proposed a framework to introduce quantum and thermal fluctuations in the kaon condensed phase on the basis of chiral symmetry, and derived the equation of state. Solving the TOV equation we obtained the equilibrium configuration of protoneutron stars and thereby discussed the possibility of the delayed collapse to black holes.3.Appearance and growth of kaon condensation under nonequilibriumWe studied in detail the characteristic features of the dynamic phase transition under chemical nonequilibrium and pointed out that the reaction rates for creation and annihilation of thermal kaons are dominant over those of other processes before and after phase transition.4.Nucleon superfluidity under pion condensation or large proton-mixing and hyperon superfluidity, and their implications on neutron-star coolingExtending the privious theory to include the DELTA isobar degrees of freedom, we found that the critical temperature and the existing region are increased due to DELTA for pi^0 condensation ; while those are reduced for pi^C condensation. In the case of large proton mixing, where proton pairs condense as well, the net effect is not efficient for neutron star cooling. A hyperon superfluidity is also studied.5.Recent experiment on Gamow-Teller resonance and pion condensation reexaminedWe reexamined the possibility of pion condensation by using the recent information from giant Gamow-Teller resonance. Consequently we remarked that it should be seriously re-considered in the context of neutron stars and heavy-ion reactions.