Aharonov–Casher Effect
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The Aharonov–Casher effect is a quantum mechanical phenomenon predicted in 1984 by Yakir Aharonov and Aharon Casher, in which a traveling magnetic dipole is affected by an
electric field An electric field (sometimes E-field) is the physical field that surrounds electrically charged particles and exerts force on all other charged particles in the field, either attracting or repelling them. It also refers to the physical field fo ...
. It is
dual Dual or Duals may refer to: Paired/two things * Dual (mathematics), a notion of paired concepts that mirror one another ** Dual (category theory), a formalization of mathematical duality *** see more cases in :Duality theories * Dual (grammatical ...
to the
Aharonov–Bohm effect The Aharonov–Bohm effect, sometimes called the Ehrenberg–Siday–Aharonov–Bohm effect, is a quantum mechanical phenomenon in which an electrically charged particle is affected by an electromagnetic potential (φ, A), despite being confined ...
, in which the quantum phase of a charged particle depends upon which side of a magnetic
flux tube A flux tube is a generally tube-like ( cylindrical) region of space containing a magnetic field, B, such that the cylindrical sides of the tube are everywhere parallel to the magnetic field lines. It is a graphical visual aid for visualizing a mag ...
it comes through. In the Aharonov–Casher effect, the particle has a
magnetic moment In electromagnetism, the magnetic moment is the magnetic strength and orientation of a magnet or other object that produces a magnetic field. Examples of objects that have magnetic moments include loops of electric current (such as electromagnets ...
and the tubes are charged instead. It was observed in a gravitational
neutron interferometer In physics, a neutron interferometer is an interferometer capable of diffracting neutrons, allowing the wave-like nature of neutrons, and other related phenomena, to be explored. Interferometry Interferometry inherently depends on the wave natu ...
in 1989 and later by
fluxon In physics, a fluxon is a quantum of electromagnetic flux. The term may have any of several related meanings. Superconductivity In the context of superconductivity, in type II superconductors fluxons (also known as Abrikosov vortices) can form ...
interference of magnetic vortices in
Josephson junctions In physics, the Josephson effect is a phenomenon that occurs when two superconductors are placed in proximity, with some barrier or restriction between them. It is an example of a macroscopic quantum phenomenon, where the effects of quantum mech ...
. It has also been seen with electrons and atoms. In both effects the particle acquires a phase shift (\varphi) while traveling along some path ''P''. In the Aharonov–Bohm effect it is :\varphi_ = \frac \int_P \mathbf \cdot d\mathbf While for the Aharonov–Casher effect it is :\varphi_ = \frac \int_P (\mathbf\times \boldsymbol \mu) \cdot d\mathbf where q is its charge and \boldsymbol \mu is the magnetic moment. The effects have been observed together.*


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See also

* Duality (electricity and magnetism) Quantum mechanics Physical phenomena {{Quantum-stub