The strongly interacting Quark Gluon Plasma, and the critical behaviour of QCD at imaginary chemical potential

Abstract

We explore the highly non-perturbative hot region of the QCD phase diagram close to Tc by use of an imaginary chemical potential mu which avoids the sign problem. The number density and the quark number susceptibility are consistent with a critical behaviour associated with the transition line in the negative mu^2 half-plane. We compare the analytic continuation of these results with various phenomenological models, none of which provides a satisfactory description of data, a failure on which we make some comments. These results complement and extend the information obtained via the analysis of the susceptibilities evaluated at zero mu, yielding a simple description of the candidate strongly interacting QGP phase. As a byproduct of our analysis we investigate the Polyakov loop and its hermitian conjugate. Our data offer a vivid evidence of the importance of the complex nature of the functional integral measure, which results in L (mu) ne \bar L(mu) for a real chemical potential.

9 pages, 10 figures; one typo fixed, beta value specified

References in corpus (5)

• The Phase Structure of the Polyakov--Quark-Meson Model
• A Model for QCD at High Density and Large Quark Mass
• Imaginary chemical potentials and the phase of the fermionic determinant
• Theoretical overview: towards understanding the quark-gluon plasma
• The Sign Problem via Imaginary Chemical Potential

Cited by in corpus (5)

• Chiral crossover, deconfinement and quarkyonic matter within a Nambu-Jona Lasinio model with the Polyakov loop
• Vector-type four-quark interaction and its impact on QCD phase structure
• The critical line from imaginary to real baryonic chemical potentials in two-color QCD
• The Approach to the Thermodynamic Limit in Lattice QCD at μ\neq0
• Quasiparticle Model of Quark-Gluon Plasma at Imaginary Chemical Potential