Surface tension of nucleating hadrons using the free energy of an isolated quark

We report on a new method of calculating the surface tension in quenched lattice QCD, in which an external field coupled to the Polyakov lines is applied to generate the interface between the confined and the deconfined phases. The free energy associated with the interface is then computed from an integral of the average Polyakov line with respect to the strength of the external field. We have tested this new approach on a 16×{}16×{}32 spatial volume, using a temporal size of Nₜ=4 for which all previous attempts at computing the surface tension have failed. A clear signal has been seen, giving αTc³=0.027(4), or α=5 MeV/fm². This represents a very small cost in free energy for hadrons to nucleate from a hot plasma.