  We discuss the mode spectrum in both the deterministic and noisy Burgers
equations in one dimension. Similar to recent investigations of vortex
depinning in superconductors, the spectrum is given by a non-Hermitian
eigenvalue problem which is related to a `quantum' problem by a complex gauge
transformation. The soliton profile in the Burgers equation serves as a complex
gauge field engendering a {\em mode transmutation} of diffusive modes into
propagating modes and giving rise to a {\em dynamical pinning} of localized
modes about the solitons.
