Computations of bubble growth during the cosmological quark-hadron transition  pp. 335-344

Computations of bubble growth during the cosmological quark-hadron transition

By J. C. Miller and O. Pantano

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Abstract. An outline is given of a scheme being used for making computations of the growth of single hadronic bubbles during the cosmological quark-hadron transition. The code uses a standard Lagrangian finite-difference scheme for flow within the bulk of each phase together with continuous tracking of the phase interface across the grid by means of a characteristic method with iterative solution of junction conditions.

INTRODUCTION

In view of the subject of this meeting, our emphasis here will be on the computational aspects of our study of the cosmological quark-hadron transition (Miller & Pantano 1989, 1990; Pantano 1989). However, as a preliminary, it is good to recall some fundamental points of the physics lying behind the calculations.

According to present ideas, hadrons are composed of quarks which move freely within a hadron but are strongly constrained from leaving. A phenomenological description of this is provided by the MIT bag model (Chodos et al 1974) where the region occupied by the quarks is associated with a false vacuum state characterized by a uniform vacuum energy density B and an associated negative pressure – B. If normal hadronic matter were compressed to high enough density, the individual hadrons would overlap and the quarks would become free to move within the entire interior region, giving rise to a quark-gluon plasma. Heavy-ion collision experiments at CERN and Brookhaven are aiming to create transient plasma in the course of collisions and to look for signatures of its decay.