Orateur
Description
One of the biggest challenges for lattice quantum chromodynamics (LQCD) at finite baryon densities is the so-called sign problem which prevents evaluations to be reliably performed within this domain. A possible technique to circumvent this problem is to perform an extrapolation from real to imaginary chemical potential, where the sign problem is overcome. An effective way to implement a finite chemical potential into the equation of state is to perform a Taylor series expansion in the chemical potential. Then, after analytically continuing the chemical potential, the main task is to obtain the Fourier coefficients, $b_k$, of the series expansion representing the first order baryon susceptibility, $\chi_1^B(T,\mu) = \sum_k b_k(T) \sinh (k \mu_B/T)$. In the present work, we consider the Polyakov--Nambu--Jona-Lasinio model (PNJL) with a repulsive vector interaction, parametrized by $G_V$, which is an essential ingredient to describe in medium properties. In order to do an optimal fitting we compare the PNJL $b_k$ coefficients, obtained at the mean-field level, with those predicted by LQCD to analyze if $G_V$ should eventually also depend on the temperature and/or chemical potential.
