Finite-size rounding of first-order transitions

Abstract

Studies of finite-size effects at the phase boundary (H=0, T<Tc) of ferromagnetic spin systems are reported for both ‘‘block’’ and ‘‘cylinder’’ geometries in d dimensions. Explicit expressions are given for universal scaling functions describing the rounded first order transition for n-component spins: The helicity modulus and the lengthwise or longitudinal correlation length, which is directly related, enter for long cylinders when n≥2.