I will examine a model of strangelets as bulk matter with the addition of these finite size effects. The total energy of the strangelet may be written as follows:
where V is the volume of the strangelet, is the fine structure constant, and the sum is over the quark flavors. For bulk strange matter, the chemical potentials for each of the quark species were approximately equal. Now, due to the presence of a coulomb energy, will differ from . The expressions for the thermodynamic potentials, , are the same as in the bulk case. A renormalization point must again be chosen for and within . This choice will ultimately affect any quantitative predictions, but the qualitative features should be independent of scale. An intuitively appropriate choice of scale for this model is the effective mass of a constituent quark, MeV. Since I am only interested in the general properties of strangelets and not in detailed predictions, I will not worry about the effects of choosing a different renormalization point. and n will also be modified due to surface effects, which may themselves depend on and . These effects may be parameterized into a surface tension, , giving rise to the second term in the total energy proportional to . The third term represents the pressure keeping the strangelet bound; B is analogous to the bag constant of bag models, and is equal to the difference in the energy of the perturbed vacuum inside the strangelet and the true QCD vacuum outside. The final term represents the coulomb energy, proportional to the square of the strangelet charge, , and assuming the charge is evenly distributed.
The ratio of quark species and the size of the strangelet can be found by minimizing this total energy with respect to the chemical potentials while the baryon number, , is held fixed.