  We have considered the quantum dynamics of an array of nSQUIDs --
two-junction SQUIDs with negative mutual inductance between their two arms.
Effective dual-rail structure of the array creates additional internal degree
of freedom for the fluxons in the array, which can be used to encode and
transport quantum information. Physically, this degree of freedom is
represented by electromagnetic excitations localized on the fluxon. We have
calculated the spatial profile and frequency spectrum of these excitations.
Their dynamics can be reduced to two quantum states, so that each fluxons
moving through the array carries with it a qubit of information. Coherence
properties of such a propagating qubits in the nSQUID array are characterized
by the dynamic suppression of the low-frequency decoherence due to the
motion-induced spreading of the noise spectral density to a larger frequency
interval.
