Effects of thermal conduction in sonoluminescence

We show by numerical hydrodynamic calculations that there are two important effects of thermal conduction in sonoluminescence: (i) the bubble remains close to being isothermal during the expansion phase; and (ii) a cold, dense layer of air is formed at the bubble wall during the contraction phase. These conclusions are not sensitive to the particular equation of state used, although details of the dynamical evolution of the bubble are

Temperature dependence of instantons in QCD

We investigate the temperature dependence of the instanton contents of gluon fields, using unquenched lattice QCD and the cooling method. The instanton size parameter deduced from the correlation function decreases from 0.44fm below the phase-transition temperature $T_c$ ($\approx 150$MeV) to 0.33fm at 1.3 $T_c$. The instanton charge distribution is Poissonian above $T_c$, but it deviates from the convoluted Poisson at low temperature. The topological susceptibility decreases rapidly below $T_c$, showing the apparent restoration of the $U(1)_A$ symmetry already at $T \approx T_c$.Comment: 8 pages TEX, 3 Postscript figures available at http://www.krl.caltech.edu/preprints/MAP.htm

Test of the Skyrme Effective Field Theory Using Quenched Lattice QCD

The Skyrme effective field theory is tested by evaluating nucleon ground state matrix elements of the correlation functions for two flavor density operators and two pseudoscalar density operators in the Skyrme model and comparing them with results in quenched lattice QCD. The possiblility of using quenched lattice QCD to study higher-order terms in effective field theory is also discussed.Comment: 20 pages in TeX, 6 figures added using "figures", MIT-CTP-200