4,141 research outputs found
Isospin Chemical Potential and the QCD Phase Diagram at Nonzero Temperature and Baryon Chemical Potential
We use the Nambu--Jona-Lasinio model to study the effects of the isospin
chemical potential on the QCD phase diagram at nonzero temperature and baryon
chemical potential. We find that the phase diagram is qualitatively altered by
a small isospin chemical potential. There are two first order phase transitions
that end in two critical endpoints, and there are two crossovers at low baryon
chemical potential. These results have important consequences for systems where
both baryon and isospin chemical potentials are nonzero, such as heavy ion
collision experiments. Our results are in complete agreement with those
recently obtained in a Random Matrix Model.Comment: 4 pages, 1 figure, REVTeX
Complex Langevin Simulations of QCD at Finite Density -- Progress Report
We simulate lattice QCD at finite quark-number chemical potential to study
nuclear matter, using the complex Langevin equation (CLE). The CLE is used
because the fermion determinant is complex so that standard methods relying on
importance sampling fail. Adaptive methods and gauge-cooling are used to
prevent runaway solutions. Even then, the CLE is not guaranteed to give correct
results. We are therefore performing extensive testing to determine under what,
if any, conditions we can achieve reliable results. Our earlier simulations at
, on a lattice reproduced the expected phase
structure but failed in the details. Our current simulations at on
a lattice fail in similar ways while showing some improvement. We are
therefore moving to even weaker couplings to see if the CLE might produce the
correct results in the continuum (weak-coupling) limit, or, if it still fails,
whether it might reproduce the results of the phase-quenched theory. We also
discuss action (and other dynamics) modifications which might improve the
performance of the CLE.Comment: Talk presented at Lattice 2017, Granada, Spain and submitted to
proceedings. 8 pages, 4 figure
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