Mike Horne and the Aharonov-Bohm Effect

One of the research topics that Mike Horne was continually returning to was the Aharonov-Bohm (A-B) effect, something he felt was under-appreciated. Even though there is no force acting on a particle for the effect to appear, the system had to have been prepared, and there were forces during this stage so the effect is not as mysterious as it appeared to be; this is illustrated here by considering one well-known case of the A-B effect. It is treated in more detail than usual for the benefit of a readership that could include philosophers or historians of science as well as physicists.