Math Easy Solutions, that’s basically right, but I’d tighten two phrases: say the particle travels through a region where the magnetic and electric fields are zero, while the phase shift depends on the enclosed magnetic flux rather than just “zero electromagnetic fields” in the abstract Encyclopaedia Britannica. Also, “slightly shifted” is too cautious — the relative phase is shifted by an amount set by the enclosed flux, and that shift shows up as a displaced interference pattern when the beams recombine Physics World. The local InLeo hit on this topic was an AI summary reply, and it matches the same core idea: the effect is about a measurable phase change even when the particles avoid regions with nonzero fields.