Editing Graviton (section)

== History ==
[[Albert Einstein]] discussed quantized gravitational radiation in 1916, the year following his publication of [[general relativity]].<ref name=Stachel1999/>{{rp|525}}
The term ''graviton'' was coined in 1934 by Soviet physicists [[Dmitry Blokhintsev]] and {{ill|Fyodor Galperin|ru|Гальперин, Фёдор Матвеевич}}.<ref name=Blokhintsev/><ref name=Stachel1999>{{cite book| chapter=The Early History of Quantum Gravity (1916–1940)| title=Black Holes, Gravitational Radiation and the Universe| date=1999| last1=Stachel| first1=John| pages=525–534| isbn=978-90-481-5121-9| series=Fundamental Theories of Physics |volume=100| doi=10.1007/978-94-017-0934-7_31}}</ref> [[Paul Dirac]] reintroduced the term in a number of lectures in 1959, noting that the energy of the gravitational field should come in quanta.<ref>{{Cite book |last=Farmelo |first=Graham |author-link=Graham Farmelo |title=The Strangest Man : The Hidden Life of Paul Dirac, Quantum Genius |publisher=Faber and Faber |year=2009 |isbn=978-0-571-22278-0 |pages=367–368 |language=en}}</ref><ref name="Debnath">{{Cite journal |last=Debnath |first=Lokenath |author-link=Lokenath Debnath |date=2013 |title=A short biography of Paul A. M. Dirac and historical development of Dirac delta function |url=http://www.tandfonline.com/doi/abs/10.1080/0020739X.2013.770091 |journal=International Journal of Mathematical Education in Science and Technology |language=en |volume=44 |issue=8 |pages=1201–1223 |doi=10.1080/0020739X.2013.770091 |bibcode=2013IJMES..44.1201D |issn=0020-739X}}</ref> A mediation of the gravitational interaction by particles was anticipated by [[Pierre-Simon Laplace]].<ref name="Zee_Gravity">{{Cite book |url=https://press.princeton.edu/books/hardcover/9780691174389/on-gravity |title=On Gravity: A Brief Tour of a Weighty Subject |last=Zee |first=Anthony |date=2018-04-24 |publisher=Princeton University Press |isbn=978-0-691-17438-9 |location=Princeton, New Jersey |language=en-us}}</ref> Just like [[Light#Particle theory|Newton's anticipation of photons]], Laplace's anticipated "gravitons" had a greater speed than the speed of light in vacuum <math>c</math>, the speed of gravitons expected in modern theories, and were not connected to [[quantum mechanics]] or [[special relativity]], since these theories didn't yet exist during Laplace's lifetime.

=== Gravitons and renormalization ===
When describing graviton interactions, the [[classical theory]] of [[Feynman diagram]]s and semiclassical corrections such as [[one-loop diagram]]s behave normally. However, Feynman diagrams with at least two loops lead to [[ultraviolet divergence]]s.<ref>{{Cite journal |last1=Bern |first1=Zvi |last2=Chi |first2=Huan-Hang |last3=Dixon |first3=Lance |last4=Edison |first4=Alex |date=2017-02-22 |title=Two-loop renormalization of quantum gravity simplified |url=https://www.slac.stanford.edu/pubs/slacpubs/16750/slac-pub-16905.pdf |journal=Physical Review D |language=en |volume=95 |issue=4 |page=046013 |arxiv=1701.02422 |doi=10.1103/PhysRevD.95.046013 |bibcode=2017PhRvD..95d6013B |issn=2470-0010}}</ref> These infinite results cannot be removed because quantized [[general relativity]] is not [[Perturbation theory (quantum mechanics)|perturbatively]] [[renormalizable]], unlike [[quantum electrodynamics]] and models such as the [[Yang–Mills theory]]. Therefore, incalculable answers are found from the perturbation method by which physicists calculate the probability of a particle to emit or absorb gravitons, and the theory loses predictive veracity. Those problems and the complementary approximation framework are grounds to show that a theory more unified than quantized general relativity is required to describe the behavior near the [[Planck scale]].