  We design fast bias inversions of an asymmetric double well so that the
lowest states in each well remain so and free from residual motional
excitation. This cannot be done adiabatically, and a sudden bias switch
produces in general motional excitation. The residual excitation is suppressed
by complementing a predetermined fast bias change with a linear ramp whose
time-dependent slope compensates for the displacement of the wells. The
process, combined with vibrational multiplexing and demultiplexing, can produce
vibrational state inversion without exciting internal states, just by deforming
the trap.
