physics Physics is the natural science that studies matter, its fundamental constituents, its motion and behavior through space and time, and the related entities of energy and force. "Physical science is that department of knowledge which r ...

, a dyon is a

hypothetical particle This is a list of known and hypothesized particles. Elementary particles Elementary particles are particles with no measurable internal structure; that is, it is unknown whether they are composed of other particles. They are the fundamental ob ...

in 4-dimensional theories with both

electric Electricity is the set of physical phenomena associated with the presence and motion of matter that has a property of electric charge. Electricity is related to magnetism, both being part of the phenomenon of electromagnetism, as described by ...

and

magnetic Magnetism is the class of physical attributes that are mediated by a magnetic field, which refers to the capacity to induce attractive and repulsive phenomena in other entities. Electric currents and the magnetic moments of elementary particle ...

charges. A dyon with a zero

electric charge Electric charge is the physical property of matter that causes charged matter to experience a force when placed in an electromagnetic field. Electric charge can be ''positive'' or ''negative'' (commonly carried by protons and electrons respe ...

is usually referred to as a

magnetic monopole In particle physics, a magnetic monopole is a hypothetical elementary particle that is an isolated magnet with only one magnetic pole (a north pole without a south pole or vice versa). A magnetic monopole would have a net north or south "magneti ...

. Many

grand unified theories A Grand Unified Theory (GUT) is a model in particle physics in which, at high energies, the three gauge interactions of the Standard Model comprising the electromagnetic, weak, and strong forces are merged into a single force. Although this ...

predict the existence of both magnetic monopoles and dyons. Dyons were first proposed by

Julian Schwinger Julian Seymour Schwinger (; February 12, 1918 – July 16, 1994) was a Nobel Prize winning American theoretical physicist. He is best known for his work on quantum electrodynamics (QED), in particular for developing a relativistically invariant ...

in 1969 as a phenomenological alternative to quarks. He extended the

Dirac quantization condition In particle physics, a magnetic monopole is a hypothetical elementary particle that is an isolated magnet with only one magnetic pole (a north pole without a south pole or vice versa). A magnetic monopole would have a net north or south "magneti ...

to the dyon and used the model to predict the existence of a particle with the properties of the J/ψ meson prior to its discovery in 1974. The allowed charges of dyons are restricted by the

. This states in particular that their magnetic charge must be integral, and that their electric charges must all be equal modulo 1. The

Witten effect Witten () is a city with almost 100,000 inhabitants in the Ennepe-Ruhr-Kreis (district) in North Rhine-Westphalia, Germany. Geography Witten is situated in the Ruhr valley, in the southern Ruhr area. Bordering municipalities * Bochum * Dortmun ...

, demonstrated by

Edward Witten Edward Witten (born August 26, 1951) is an American mathematical and theoretical physicist. He is a Professor Emeritus in the School of Natural Sciences at the Institute for Advanced Study in Princeton. Witten is a researcher in string theory, q ...

in his 1979 paper, states that the electric charges of dyons must all be equal, modulo one, to the product of their magnetic charge and the theta angle of the theory. In particular, if a theory preserves

CP symmetry In particle physics, CP violation is a violation of CP-symmetry (or charge conjugation parity symmetry): the combination of C-symmetry (charge symmetry) and P-symmetry (parity symmetry). CP-symmetry states that the laws of physics should be the ...

then the electric charges of all dyons are

integer An integer is the number zero (), a positive natural number (, , , etc.) or a negative integer with a minus sign (−1, −2, −3, etc.). The negative numbers are the additive inverses of the corresponding positive numbers. In the language ...

References

External links

* {{cite journal , last1=Chanyal , first1=B. C. , last2=Bisht , first2=P. S. , last3=Negi , first3=O. P. S. , title=Generalized Octonion Electrodynamics , journal=International Journal of Theoretical Physics , volume=49 , issue=6 , date=1 March 2010 , issn=0020-7748 , doi=10.1007/s10773-010-0314-5 , pages=1333–1343, arxiv=0910.1451 , bibcode=2010IJTP...49.1333C , s2cid=118377495
Electromagnetic duality for children
lecture notes by José Figueroa-O'Farrill Gauge theories Magnetic monopoles Physics beyond the Standard Model