LOGARITHMIC CORRECTIONS TO SCALING IN THE XY(2)-MODEL

We study the distribution of partition function zeroes for the XY-mode l in two dimensions. In particular we find the scaling behaviour of th e end of the distribution of zeroes in the complex external magnetic f ield plane in the thermodynamic limit (the Yang-Lee edge) and the form for the density of these zeroes. Assuming that finite-size scaling ho lds, we show that there have to exist logarithmic corrections to the l eading scaling behaviour of thermodynamic quantities in this model. Th ese logarithmic corrections are also manifest in the finite-size scali ng formulae and we identify them numerically. The method presented her e can be used to check the compatibility of scaling behaviour of odd a nd even thermodynamic functions in other models too.