Dispersion Law of Edge Waves in the Quantum Hall Effect

We present a microscopic description of edge excitations in the quantum Hall effect which is analogous to Feynman's theory of superfluids. Analytic expressions for the excitation energies are derived in finite dots. Our predictions are in excellent agreement with the results of a recent numerical diagonalization. In the large $N$ limit the dispersion law is proportional to $qlog{1\over q}$. For short range interactions the energy instead behaves as $q^3$. The same results are also derived using hydrodynamic theory of incompressible liquids.