Tai Tsun Wu and Yang Chen-Ning theorized a non-abelian form of this effect that lacks time-reversal symmetry. In 2022, Chris Overstreet et al. used interferometry to experimentally observe a gravitational analog of this effect. In the Little-Parks effect, the BCS condensate (-5[1])experiences this other effect, causing the superconducting critical (-5[1])temperature to vary. In a gauge-invariant equation describing this effect, action over (*) h bar equals q over h bar c times the magnetic flux. This effect is a special case of a holonomy named for Berry that is produced by cyclic adiabatic processes. The magnitude of this effect is proportional to the line integral of the vector potential, which is sometimes argued to have physical significance due to this effect. For 10 points, name this effect in which particles pick up a phase as they move through a region with no electric or magnetic field. ■END■ (0[4])