graviton

In theories of quantum gravity, the graviton is the hypothetical elementary particle that mediates the force of gravitational interaction. It is a quantum of gravitational wave energy. There is no complete quantum field theory of gravitons due to the unsolved mathematical problem of renormalization in general relativity. This problem is avoided in string theory, which has the graviton as a massless state of a fundamental string, but that theory has not made sufficient progress.

AI overview

A graviton is a theoretical particle that would carry the force of gravity in the same way that photons carry light, according to quantum physics theories. Scientists haven't yet been able to fully work out the mathematical details of how gravitons would work, though some theories like string theory propose solutions that remain unproven.

AI-generated from the Wikipedia summary — may contain errors.

Key facts

Particle.symbol: G
Particle.mass: 0
Particle.name: Graviton
Particle.composition: Elementary particle
Particle.statistics: Bose–Einstein statistics
Particle.group: Bosonic
Particle.interaction: Gravitation
Particle.status: Hypothetical
Particle.theorized: 1930sThe name is attributed to Dmitry Blokhintsev and F. M. Gal'perin in 1934
Particle.mean_lifetime: stable
Particle.electric_charge: 0 e
Particle.color_charge: No
Particle.spin: 2 ħ
Particle.num_spin_states: +2 ħ,  −2 ħ
Particle.parity: +1
Particle.c_parity: +1

via Wikipedia infobox

Wikidata facts

Mass: 0
Image: Fundamental Interactions.png
Speed: 299792458

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Monte Carlo Particle Number: 39
spin quantum number: 2
electric charge: 0
parity quantum number: 1
mean lifetime: 1
Commons category: Gravitons

Sources (6)

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~7 min read

Article

9 sections

Contents

Theory
History
Gravitons and renormalization
Energy and wavelength
Experimental observation
Difficulties and outstanding issues
See also
References
External links

If it exists, the graviton is expected to be massless because the gravitational force has a very long range and appears to propagate at the speed of light. The graviton must be a spin-2 boson because the source of gravitation is the stress–energy tensor, a second-order tensor (compared with electromagnetism's spin-1 photon, the source of which is the four-current, a first-order tensor). Additionally, it can be shown that any massless spin-2 field would give rise to a force indistinguishable from gravitation, because a massless spin-2 field would couple to the stress–energy tensor in the same way gravitational interactions do. This result suggests that, if a massless spin-2 particle is discovered, it must be the graviton.