“…This debate is currently unsettled. Many papers have addressed this debate [43,44,45,46,47,48,49,50,51,52] and proposed other models that intend to explain the AB effect [53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76]. This debate may be naturally translated to the case of the AB effect involving a vector potential outside a closed flux line and a magnetic field confined along this closed flux line.…”