STUDY OF THE COULOMB-HIGGS TRANSITION IN THE ABELIAN HIGGS-MODEL

The order of the Coulomb-Higgs transition in the U(1)-Higgs model with unfrozen modulus of the scalar field is studied. Large lattices (up t o 24(4) in one case) and high statistics are used. We fix beta=1.15 an d explore specially a region of lambda-values where metastability is o bserved. We study the thermodynamical limit of several observables, in particular, the latent heat, the specific heat, the decrement of the free energy between the maxima and the central minimum of the two-peak ed histogram, the Binder cumulant and the displacement of the critical coupling with the lattice size. The results point towards a second or der transition for lambda greater than or similar to 0.005, while for smaller values of lambda the strong metastability growing with the lat tice size seems to derive from a first order character. (C) 1998 Elsev ier Science B.V.