Editing Degenerate matter (section)

== History ==

In 1914 [[Walther Nernst]] described the reduction of the [[specific heat]] of [[ideal gas|gases]] at very low temperature as "degeneration"; he attributed this to quantum effects.  In subsequent work in various papers on [[quantum thermodynamics]] by [[Albert Einstein]], by [[Max Planck]], and by [[Erwin Schrödinger]], the effect at low temperatures came to be called "gas degeneracy".<ref>Hanle, Paul A. "The Coming of Age of Erwin Schrödinger: His Quantum Statistics of Ideal Gases". Archive for History of Exact Sciences, vol. 17, no. 2, 1977, pp. 165–92. JSTOR, http://www.jstor.org/stable/41133485. Accessed 27 July 2023.</ref> A fully degenerate gas has no volume dependence on pressure when temperature approaches [[absolute zero]].

Early in 1927 [[Enrico Fermi]] and separately [[Llewellyn Thomas]] developed a semi-classical model for electrons in a metal.<ref>{{cite journal|last=Fermi|first=E.|author-link=Enrico Fermi|date=1926-11-01|title=Zur Quantelung des idealen einatomigen Gases|url=https://ethw.org/w/images/e/e5/P1_1926_Zur_Quantelung_des_idealen_einatomigen_Gases.pdf|archive-url=https://web.archive.org/web/20190406201635/https://ethw.org/w/images/e/e5/P1_1926_Zur_Quantelung_des_idealen_einatomigen_Gases.pdf|url-status=dead|archive-date=2019-04-06|journal=Zeitschrift für Physik|language=de|volume=36|issue=11–12|pages=902–912|doi=10.1007/BF01400221|issn=0044-3328|bibcode=1926ZPhy...36..902F|s2cid=123334672}}</ref><ref>{{Cite arXiv |last=Zannoni |first=Alberto |date=1999 |title=On the Quantization of the Monoatomic Ideal Gas |eprint=cond-mat/9912229 |quote=An english translation of the original work of Enrico Fermi on the quantization of the monoatomic ideal gas, is given in this paper}}</ref> The model treated the electrons as a gas. Later in 1927, [[Arnold Sommerfeld]] applied the Pauli principle via [[Fermi-Dirac statistics]] to this electron gas model, computing the specific heat of metals; the result became [[Fermi gas]] model for metals. Sommerfeld called the low temperature region with quantum effects a "wholly degenerate gas".<ref>{{Cite journal |last=Eckert |first=Michael |date=1987-01-01 |title=Propaganda in Science: Sommerfeld and the Spread of the Electron Theory of Metals |url=https://online.ucpress.edu/hsns/article/17/2/191/47697/Propaganda-in-Science-Sommerfeld-and-the-Spread-of |journal=Historical Studies in the Physical and Biological Sciences |language=en |volume=17 |issue=2 |pages=191–233 |doi=10.2307/27757582 |jstor=27757582 |issn=0890-9997|url-access=subscription }}</ref>

The concept of '''degenerate stars''', stellar objects composed of degenerate matter, was originally developed in a joint effort between [[Arthur Eddington]], [[Ralph Fowler]] and [[Arthur Milne]]. Eddington had suggested that the atoms in [[Sirius|Sirius B]] were almost completely ionised and closely packed. Fowler described white dwarfs as composed of a gas of particles that became degenerate at low temperature; he also pointed out that ordinary atoms are broadly similar in regards to the filling of energy levels by fermions.<ref>{{Cite journal|last=Fowler|first=R. H.|date=1926-12-10|title=On Dense Matter|url=https://academic.oup.com/mnras/article/87/2/114/1058897|journal=Monthly Notices of the Royal Astronomical Society|language=en|volume=87|issue=2|pages=114–122|doi=10.1093/mnras/87.2.114|issn=0035-8711|bibcode=1926MNRAS..87..114F|doi-access=free}}</ref> In 1926, Milne proposed that degenerate matter is found in core of stars, not only in [[compact star]]s.<ref>{{Cite book|title=A History of Astronomy : from 1890 to the Present|last=David.|first=Leverington|date=1995|publisher=Springer London|isbn=1447121244|location=London|oclc=840277483}}</ref>
In 1927 [[Ralph H. Fowler]] applied Fermi's model to the puzzle of the stability of white dwarf stars. This approach was extended to relativistic models by later studies and with the work of [[Subrahmanyan Chandrasekhar]] became the accepted [[Chandrasekhar limit|   model for star stability]].<ref>{{Cite journal |last1=Koester |first1=D |last2=Chanmugam |first2=G |date=1990-07-01 |title=Physics of white dwarf stars |url=https://iopscience.iop.org/article/10.1088/0034-4885/53/7/001 |journal=Reports on Progress in Physics |volume=53 |issue=7 |pages=837–915 |doi=10.1088/0034-4885/53/7/001 |s2cid=250915046 |issn=0034-4885|url-access=subscription }}</ref>