Győző Kovács [1], Péter Kovács [1], György Wolf [1], Pok Man Lo [2] (2023.01.01 - 11.30)

[1] Wigner Research Centre for Physics
[2] University of Wroclaw, Wroclaw

Grant: NKFIH FK 131982

Publication: Sensitivity of finite size effects to the boundary conditions and the vacuum term

Abstract: The effect of finite size/volume in effective field theory models is usually accounted for by some form of constrain in the momentum space, for example by low momentum cut-off or discretization. The latter results in a summation for momentum modes depending on the boundary condition used, rather than integrals. We study the size dependence of the baryon fluctuations in and around the critical endpoint in an improved quark-meson model, with particular attention to how they are affected by different modifications of the momentum space and the inclusion of the vacuum contribution. To determine the cumulant ratios describing the fluctuations, the higher order derivatives of the pressure are calculated. For this purpose, the finite difference method can be used, but this requires solving the field equations at several points for the derivative at only one point. This demands considerable computational power if the phase diagram and the size dependence are to be computed densely enough. On the other hand these calculations can be easily parallelised.