Volume dependence of baryon number cumulants and their ratios

GA Almási, RD Pisarski, VV Skokov - Physical Review D, 2017 - APS
Physical Review D, 2017APS
We explore the influence of finite-volume effects on cumulants of baryon/quark number
fluctuations in a nonperturbative chiral model. In order to account for soft modes, we use the
functional renormalization group in a finite volume, using a smooth regulator function in
momentum space. We compare the results for a smooth regulator with those for a sharp (or
Litim) regulator, and show that in a finite volume, the latter produces spurious artifacts. In a
finite volume there are only apparent critical points, about which we compute the ratio of the …
We explore the influence of finite-volume effects on cumulants of baryon/quark number fluctuations in a nonperturbative chiral model. In order to account for soft modes, we use the functional renormalization group in a finite volume, using a smooth regulator function in momentum space. We compare the results for a smooth regulator with those for a sharp (or Litim) regulator, and show that in a finite volume, the latter produces spurious artifacts. In a finite volume there are only apparent critical points, about which we compute the ratio of the fourth- to the second-order cumulant of quark number fluctuations. When the volume is sufficiently small the system has two apparent critical points; as the system size decreases, the location of the apparent critical point can move to higher temperature and lower chemical potential.
American Physical Society