Experimental Observation of Time-Delays Associated with Electric Matteucciâ•fiPozzi Phase Shifts

In 1985, Matteucci and Pozzi (1985 Phys. Rev. Lett. 54 2469) demonstrated the presence of a quantum mechanical phase shift for electrons passing a pair of oppositely charged biprism wires. For this experimental arrangement no forces deflect the electrons. Consequently, the result was reported as a non-local type-2 Aharonov–Bohm effect. Boyer (2002 Found. Phys. 32 41–50; 1987 Nuovo Cimento B 100 685–701) showed theoretically that the Matteucci–Pozzi effect could be associated with a time delay caused by a classical force. We present experimental data that confirm the presence of a time delay. This result is in contrast to the situation for the original magnetic Aharonov–Bohm effect. On similar theoretical grounds, Boyer has also associated classical forces and time delays with the magnetic Aharonov–Bohm effect. Recently, we reported the absence of such observable time delays. The contrast with our current work illustrates the subtle nature of Aharonov–Bohm effects. In their now famous 1959 paper [1], Aharonov and Bohm (AB) outlined two experiments to demonstrate effects that are purely quantum mechanical in nature. While this view has generated much discussion and controversy, it is now generally accepted that the effects AB outline illustrate the manner in which electromagnetic potentials can influence a system without a classical force present. AB proposed the use of magnetic flux enclosed in an electron interferometer to cause the phase shift [1]. Chambers, following the proposal, demonstrated the now famous magnetic (or vector) AB-effect [2]. Later efforts [3–6] include Tonomura’s 3 Author to whom any correspondence should be addressed. New Journal of Physics 13 (2011) 093025 1367-2630/11/093025+09$33.00 © IOP Publishing Ltd and Deutsche Physikalische Gesellschaft