6 research outputs found
Numerical study of the equation of state for two flavor QCD at finite density
We discuss the equation of state for 2 flavor QCD at non-zero temperature and
density. Derivatives of with respect to quark chemical potential
up to fourth order are calculated, enabling estimates of the pressure,
quark number density and associated susceptibilities as functions of
via a Taylor series expansion. It is found that the fluctuations in the quark
number density increase in the vicinity of the phase transition temperature and
the susceptibilities start to develop a pronounced peak as is
increased. This suggests the presence of a critical endpoint in the plane.Comment: 5 pages, 4 figures, Talk at Confinement 200
QCD at non-zero chemical potential and temperature from the lattice
A study of QCD at non-zero chemical potential, mu, and temperature, T, is
performed using the lattice technique. The transition temperature (between the
confined and deconfined phases) is determined as a function of mu and is found
to be in agreement with other work. In addition the variation of the pressure
and energy density with mu is obtained for small positive mu. These results are
of particular relevance for heavy-ion collision experiments.Comment: Invited paper presented at the Joint Workshop on Physics at the
Japanese Hadron Facility, March 2002, Adelaide. 10 pages, uses
ws-procs9x6.cls style file (provided
The Equation of State for Two Flavor QCD at Non-zero Chemical Potential
We present results of a simulation of QCD on a 4x16^3 lattice with 2
continuum flavors of p4-improved staggered fermion with mass m/T=0.4.
Derivatives of the thermodynamic grand potential with respect to quark chemical
potential mu_q up to fourth order are calculated, enabling estimates of the
pressure, quark number density and associated susceptibilities as functions of
mu_q via Taylor series expansion. Discretisation effects associated with
various staggered fermion formulations are discussed in some detail. In
addition it is possible to estimate the radius of convergence of the expansion
as a function of temperature. We also discuss the calculation of energy and
entropy densities which are defined via mixed derivatives of the thermodynamic
grand potential with respect to the bare couplings and quark masses.Comment: 30 pages, LaTeX2e File, 17 Postscript figure
The QCD thermal phase transition in the presence of a small chemical potential
We propose a new method to investigate the thermal properties of QCD with a
small quark chemical potential . Derivatives of the phase transition point
with respect to are computed at for 2 flavors of p-4 improved
staggered fermions with on a lattice. The resulting
Taylor expansion is well behaved for the small values of relevant for RHIC phenomenology, and predicts a critical curve
in reasonable agreement with estimates obtained using exact
reweighting. In addition, we contrast the case of isoscalar and isovector
chemical potentials, quantify the effect of on the equation of
state, and comment on the complex phase of the fermion determinant in QCD with
.Comment: 26 pages, 25 figures, minor modificatio
News from Lattice QCD on Heavy Quark Potentials and Spectral Functions of Heavy Quark States
We discuss recent lattice results on in-medium properties of hadrons and
focus on thermal properties of heavy quark bound states. We will clarify the
relation between heavy quark free energies and potentials used to analyze the
melting of heavy quark bound states. Furthermore, we present calculations of
meson spectral functions which indicate that the charmonium ground states,
J/psi and eta_c, persist in the quark gluon plasma as well defined resonances
with no significant change of their zero temperature masses at least up to T ~
1.5 T_c. We also briefly comment on the current status of lattice calculations
at non-vanishing baryon number density.Comment: Plenary talk at the 17th International Conference on Ultra
Relativistic Nucleus-Nucleus Collisions (Quark Matter 2004), Oakland,
California, 11-17 Jan 2004. Submitted to J.Phys.