The Bohm and Aharonov paper

F.J. Duarte

Apostol Vourdas

A unified approach to Aharonov-Bohm, Aharonov-Casher and which-path experiments is presented, using an enlarged Hilbert space. This Hilbert space contains quasi-periodic Aharonov-Bohm wavefunctions R ( x +2 ) = R ( x )exp(i ) with various values of . Thus it can describe which-path Aharonov-Bohm experiments where the phase is uncertain due to decoherence that occurs as a result of the observation of the paths of the electric charges. The same Hilbert space contains quasi-periodic Aharonov-Casher wavefunctions which describe magnetic flux tubes winding around an electric charge and which are related through a Fourier transform to the Aharonov-Bohm wavefunctions. The duality between these two phenomena is discussed. The decoherence occuring in which-path experiments is studied quantitatively. Magnetic and electric superselection rules, appropriate for the Aharonov-Bohm and Aharonov-Casher experiments correspondingly, are also discussed.

David K. Ferry

Erik Sjöqvist

It is shown that the molecular Aharonov-Bohm effect is neither nonlocal nor topological in the sense of the standard magnetic Aharonov-Bohm effect. It is further argued that there is a close relationship between the molecular Aharonov-Bohm effect and the Aharonov-Casher effect for an electrically neutral spin -1 / 2 particle encircling a line of charge.

Anton Zeilinger

Edouard B Sonin

The Aharonov–Bohm effect was discovered as a quantum-mechanical effect for charged particles, but it has its counterpart in classical wave mechanics. The Aharonov–Bohm interference arises at the scattering of a sound wave by a vortex in classical and quantum hydrodynamics. This interference leads to a transverse force between quasiparticles and vortices in superfluids and superconductors. The Aharonov–Bohm effect was also generalized to neutral particles with magnetic or electric dipole momenta. The Aharonov–Bohm effect for charge particles and its modification for magnetic momenta (the Aharonov–Casher effect) have already been experimentally observed, and the efforts to detect the Aharonov–Bohm effect for electrically polarized neutral particles are on the way. A possible system for this detection is a Bose-condensate of excitons in a double quantum well. Observation of the Aharonov–Bohm effect in this system would provide direct evidence of Bose–Einstein condensation.