In quantum field theory, a force carrier (also known as a messenger particle, intermediate particle, or exchange particle)[1] is a type of particle that gives rise to forces between other particles. These particles serve as the quanta of a particular kind of physical field.[2][3]
Quantum field theories describe nature in terms of fields. Each field has a complementary description as the set of particles of a particular type. A force between two particles can be described either as the action of a force field generated by one particle on the other, or in terms of the exchange of virtual force carrier particles between them.[4]
Gravity is not a part of the Standard Model, but it is thought that there may be particles called gravitons which are the excitations of gravitational waves. The status of this particle is still tentative, because the theory is incomplete and because the interactions of single gravitons may be too weak to be detected.[5]
A Feynman diagram of scattering between two electrons by emission of a virtual photon.
When one particle scatters off another, altering its trajectory, there are two ways to think about the process. In the field picture, we imagine that the field generated by one particle caused a force on the other. Alternatively, we can imagine one particle emitting a virtual particle which is absorbed by the other. The virtual particle transfers momentum from one particle to the other. This particle viewpoint is especially helpful when there are a large number of complicated quantum corrections to the calculation since these corrections can be visualized as Feynman diagrams containing additional virtual particles.
Another example involving virtual particles is beta decay where a virtual W boson is emitted by a nucleon and then decays to e± and (anti)neutrino.
The description of forces in terms of virtual particles is limited by the applicability of the perturbation theory from which it is derived. In certain situations, such as low-energy QCD and the description of bound states, perturbation theory breaks down.
Historyedit
The concept of messenger particles dates back to the 18th century when the French physicist Charles Coulomb showed that the electrostatic force between electrically charged objects follows a law similar to Newton's Law of Gravitation. In time, this relationship became known as Coulomb's law. By 1862, Hermann von Helmholtz had described a ray of light as the "quickest of all the messengers". In 1905, Albert Einstein proposed the existence of a light-particle in answer to the question: "what are light quanta?"
In 1923, at the Washington University in St. Louis, Arthur Holly Compton demonstrated an effect now known as Compton scattering. This effect is only explainable if light can behave as a stream of particles and it convinced the physics community of the existence of Einstein's light-particle. Lastly, in 1926, one year before the theory of quantum mechanics was published, Gilbert N. Lewis introduced the term "photon", which soon became the name for Einstein's light particle.[6] From there, the concept of messenger particles developed further, notably to massive force carriers (e.g. for the Yukawa potential).
^Rothman, Tony; Stephen Boughn (November 2006). "Can Gravitons be Detected?". Foundations of Physics. 36 (12): 1801–1825. arXiv:gr-qc/0601043. Bibcode:2006FoPh...36.1801R. doi:10.1007/s10701-006-9081-9. S2CID 14008778.
^Kragh, Helge (2014). "Photon: New light on an old name". arXiv:1401.0293 [physics.hist-ph].
January 01, 1970
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It has been suggested that Static forces and virtual particle exchange be merged into this article Discuss Proposed since December 2023 For the song see Force Carrier In quantum field theory a force carrier also known as a messenger particle intermediate particle or exchange particle 1 is a type of particle that gives rise to forces between other particles These particles serve as the quanta of a particular kind of physical field 2 3 Contents 1 Particle and field viewpoints 2 Forces from the particle viewpoint 3 History 4 See also 5 ReferencesParticle and field viewpoints editMain article Wave particle duality Quantum field theories describe nature in terms of fields Each field has a complementary description as the set of particles of a particular type A force between two particles can be described either as the action of a force field generated by one particle on the other or in terms of the exchange of virtual force carrier particles between them 4 The energy of a wave in a field for example electromagnetic waves in the electromagnetic field is quantized and the quantum excitations of the field can be interpreted as particles The Standard Model contains the following particles each of which is an excitation of a particular field Gluons excitations of the strong gauge field Photons W bosons and Z bosons excitations of the electroweak gauge fields Higgs bosons excitations of one component of the Higgs field which gives mass to fundamental particles In addition composite particles such as mesons as well as quasiparticles can be described as excitations of an effective field Gravity is not a part of the Standard Model but it is thought that there may be particles called gravitons which are the excitations of gravitational waves The status of this particle is still tentative because the theory is incomplete and because the interactions of single gravitons may be too weak to be detected 5 Forces from the particle viewpoint editMain article Static forces and virtual particle exchange nbsp A Feynman diagram of scattering between two electrons by emission of a virtual photon When one particle scatters off another altering its trajectory there are two ways to think about the process In the field picture we imagine that the field generated by one particle caused a force on the other Alternatively we can imagine one particle emitting a virtual particle which is absorbed by the other The virtual particle transfers momentum from one particle to the other This particle viewpoint is especially helpful when there are a large number of complicated quantum corrections to the calculation since these corrections can be visualized as Feynman diagrams containing additional virtual particles Another example involving virtual particles is beta decay where a virtual W boson is emitted by a nucleon and then decays to e and anti neutrino The description of forces in terms of virtual particles is limited by the applicability of the perturbation theory from which it is derived In certain situations such as low energy QCD and the description of bound states perturbation theory breaks down History editThe concept of messenger particles dates back to the 18th century when the French physicist Charles Coulomb showed that the electrostatic force between electrically charged objects follows a law similar to Newton s Law of Gravitation In time this relationship became known as Coulomb s law By 1862 Hermann von Helmholtz had described a ray of light as the quickest of all the messengers In 1905 Albert Einstein proposed the existence of a light particle in answer to the question what are light quanta In 1923 at the Washington University in St Louis Arthur Holly Compton demonstrated an effect now known as Compton scattering This effect is only explainable if light can behave as a stream of particles and it convinced the physics community of the existence of Einstein s light particle Lastly in 1926 one year before the theory of quantum mechanics was published Gilbert N Lewis introduced the term photon which soon became the name for Einstein s light particle 6 From there the concept of messenger particles developed further notably to massive force carriers e g for the Yukawa potential See also edit nbsp Physics portal Virtual particle Fundamental interaction ExcitonReferences edit Exchange Particles Jaeger Gregg 2021 Exchange Forces in Particle Physics Foundations of Physics 51 1 13 Bibcode 2021FoPh 51 13J doi 10 1007 s10701 021 00425 0 S2CID 231811425 Steven Weinberg Dreams of a Final Theory Hutchinson 1993 Jaeger Gregg 2019 Are virtual particles less real PDF Entropy 21 2 141 Bibcode 2019Entrp 21 141J doi 10 3390 e21020141 PMC 7514619 PMID 33266857 Rothman Tony Stephen Boughn November 2006 Can Gravitons be Detected Foundations of Physics 36 12 1801 1825 arXiv gr qc 0601043 Bibcode 2006FoPh 36 1801R doi 10 1007 s10701 006 9081 9 S2CID 14008778 Kragh Helge 2014 Photon New light on an old name arXiv 1401 0293 physics hist ph Retrieved from https en wikipedia org w index php title Force carrier amp oldid 1192966936, wikipedia, wiki, book, books, library,
