“…Yakir Aharonov and David Bohm [4] have argued that the (magnetic) potential can influence the physics of a quantum particle, even when the particle does not directly interact with the magnetic field (see [23] for an earlier, although more restricted, discussion). Such kind of influence has been verified in scattering operators and cross sections (see [4,34,17,2,33,8,19] to mention just some possible references) and, in some cases, in the Hamiltonian eigenvalues [31,26,21]. Of course such influence can be detected in other quantities derived from eigenvalues and/or scattering operators.…”