  Since the recent experimental realization of synthetic Rashba spin-orbit
coupling paved a new avenue for exploring and engineering topological phases in
ultracold atoms, a precise, solid detection of Berry phase has been desired for
unequivocal characterization of system topology. Here, we propose a scheme to
conduct momentum-space Aharonov-Bohm interferometry in a Rashba spin-orbit
coupled Bose-Einstein condensate with a sudden change of in-plane Zeeman field,
capable of measuring the Berry phase of Rashba energy bands. We find that the
Berry phase with the presence of a Dirac point is directly revealed by a robust
dark interference fringe, and that as a function of external Zeeman field is
characterized by the contrast of fringes. We also build a variational model
describing the interference process with semiclassical equations of motion of
essential dynamical quantities, which lead to agreeable trajectories and
geometric phases with the real-time simulation of Gross-Pitaevskii equation.
Our study would provide timely guidance for the experimental detection of Berry
phase in ultracold atomic systems and help further investigation on their
interference dynamics in momentum space.

Quantum Gases