  We study the case of open string theory on a D1-brane in a critical electric
field. It was argued in hep-th/0006085 that the massless open string modes of
this theory decouple from the massive modes, corresponding to a decoupling of
the U(1) degrees of freedom in the U(N) gauge theory dual. To provide further
support for the decoupling, we present several examples of open string disk
amplitudes. Because of the decoupling, many of the massive open string states
are stable, indicating the presence of a number of correspondingly stable
states in the gauge theory. We provide a lengthy list of these stable states.
However, when the theory is compactified in the spatial direction of the
electric field, we demonstrate that sufficiently massive such states may decay
into wound closed strings.
