13 research outputs found
Static and Dynamic Critical Phenomena at a Second Order QCD Phase Transition
In QCD with two flavors of massless quarks, the chiral phase transition is
plausibly in the same universality class as the classical four component
Heisenberg antiferromagnet. Therefore, renormalization group techniques
developed in the study of phase transitions can be applied to calculate the
critical exponents which characterize the scaling behaviour of universal
quantities near the critical point. This approach to the QCD phase transition
has implications both for lattice gauge theory and for heavy ion collisions.
Future lattice simulations with longer correlation lengths will be able to
measure the various exponents and the equation of state for the order parameter
as a function of temperature and quark mass which we describe. In a heavy ion
collision, the consequence of a long correlation length would be large
fluctuations in the number ratio of neutral to charged pions. Unfortunately, we
show that this phenomenon will not occur if the plasma stays close to
equilibrium as it cools. If the transition is far out of equilibrium and can be
modelled as a quench, it is possible that large volumes of the plasma with the
pion field correlated will develop, with dramatic phenomenological
consequences. }Comment: phyzzx, 41 pages, 4 figures available as a postscript file from K.R.,
PUPT-1347, IASSNS-HEP-92/6
Effect of retardation on dynamical mass generation in two-dimensional QED at finite temperature
The effect of retardation on dynamical mass generation in is studied, in the
imaginary time formalism. The photon porarization tensor is evaluated to
leading order in 1/N (N is the number of flavours), and simple closed form
expressions are found for the fully retarded longitudinal and transverse
propagators, which have the correct limit when T goes to zero. The resulting
S-D equation for the fermion mass (at order 1/N) has an infrared divergence
associated with the contribution of the transverse photon propagator; only the
longitudinal contribution is retained, as in earlier treatments. For solutions
of constant mass, it is found that the retardation reduces the value of the
parameter r (the ratio of twice the mass to the critical temperature) from
about 10 to about 6. The gap equation is then solved allowing for the mass to
depend on frequency. It was found that the r value remained close to 6.
Possibilities for including the transverse propagator are discussed.Comment: 26 pages 8 figure
Thermodynamics of 1-flavor QCD
We present first results, for heavy to moderate quark masses, of a study of thermodynamic properties of 1-flavor QCD, using the multiboson algorithm