 Michael Berry (physicist)

Michael Berry (physicist) showed that slowly carrying a nondegenerate energy eigenstate around a closed loop of external parameters can produce a geometric phase in addition to its dynamical phase. The geometric phase depends on the path through parameter space and survives after the ordinary energy-dependent contribution is removed. For a spin following a slowly varying magnetic field, it is proportional to the solid angle enclosed by the field direction, making the geometry measurable through interference.^[ref]

A theoretical physicist whose work includes geometric phases in quantum mechanics.