Solitons on the edge of a two-dimensional electron system

We study the excitations at the edge of a two-dimensional electron droplet in a magnetic field in terms of a contour dynamics formalism. We find that, beyond the usual Linear approximation, the nonlinear analysis yields solit on solutions which correspond to uniformly rotating shapes. These modes are found from a perturbative treatment of a nonlinear eigenvalue problem and as solutions to a modified Korteweg-de Vries equation resulting from a loca l induction approximation to the nonlocal contour dynamics. We discuss appl ications to the edge modes in the quantum Hall effect. [S0031-9007(98)08266 -0].