  We propose an optoelectronic scheme to define and manipulate an indirect
neutral exciton qubit within a quantum dot molecule. We demonstrate coherent
dynamics of indirect excitons resilient against decoherence effects, including
direct exciton spontaneous recombination. For molecules with large interdot
separation, the exciton dressed spectrum yields an often overlooked avoided
crossing between spatially indirect exciton states. Effective two level system
Hamiltonians are extracted by Feshbach projection over the multilevel exciton
configurations. An adiabatic manipulation of the qubit states is devised using
time dependent electric field sweeps. The exciton dynamics yields the necessary
conditions for qubit initialization and near unitary rotations in the
picosecond time scale, driven by the system internal dynamics. Despite the
strong influence of laser excitation, charge tunneling, and interdot
dipole-dipole interactions, the effective relaxation time of indirect excitons
is much longer than the direct exciton spontaneous recombination time,
rendering indirect excitons as potential elemental qubits in more complex
schemes.
