Editing Negative temperature (section)

=== Two-dimensional vortex motion ===
The two-dimensional systems of vortices confined to a finite area can form thermal equilibrium states at negative temperature,<ref>{{cite journal
 |last1=Montgomery |first1=D. C.
 |year=1972
 |title=Two-dimensional vortex motion and "negative temperatures"
 |journal=[[Physics Letters A]]
 |volume=39 |issue=1 |pages=7–8
 |bibcode=1972PhLA...39....7M
 |doi=10.1016/0375-9601(72)90302-7
}}</ref><ref>{{cite journal
 |last1=Edwards |first1=S. F. |author-link1=Sam Edwards (physicist)
 |last2=Taylor |first2=J. B. |author-link2=J. Bryan Taylor
 |year=1974
 |title=Negative Temperature States of Two-Dimensional Plasmas and Vortex Fluids
 |journal=[[Proceedings of the Royal Society of London A]]
 |volume=336 |issue=1606 |pages=257–271
 |bibcode=1974RSPSA.336..257E
 |doi=10.1098/rspa.1974.0018
 |jstor=78450
|s2cid=120771020 }}</ref> and indeed negative temperature states were first predicted by Onsager in his analysis of classical point vortices.<ref>{{Cite journal| doi = 10.1007/BF02780991| issn = 1827-6121| volume = 6| issue = 2| pages = 279–287| last = Onsager| first = L.| title = Statistical hydrodynamics| journal = Il Nuovo Cimento (1943-1954)| accessdate = 2019-11-17| date = 1949-03-01| bibcode = 1949NCim....6S.279O| s2cid = 186224016| url = https://doi.org/10.1007/BF02780991| url-access = subscription}}</ref> Onsager's prediction was confirmed experimentally for a system of [[Quantum vortex|quantum vortices]] in a Bose–Einstein condensate in 2019.<ref name=Gau19>{{cite journal |last1=Gauthier |first1=G. |last2=Reeves |first2=M. T. |last3=Yu |first3=X. |last4=Bradley |first4=A. S.|last5=Baker|first5=M. A.|last6=Bell|first6=T. A.|last7=Rubinsztein-Dunlop|first7=H.|last8=Davis|first8=M. J.|last9=Neely|first9=T. W. |year=2019 |title=Giant vortex clusters in a two-dimensional quantum fluid |journal=Science |volume=364 |issue= 6447|pages=1264–1267 |doi=10.1126/science.aat5718 |pmid=31249054 |arxiv= 1801.06951|bibcode= 2019Sci...364.1264G|s2cid=195750381 }}</ref><ref>{{cite journal |last1=Johnstone |first1=S. P. |last2=Groszek|first2=A. J.|last3=Starkey|first3=P. T.|last4=Billinton|first4=C. J.|last5=Simula|first5=T. P.|last6=Helmerson|first6=K.|year=2019 |title= Evolution of large-scale flow from turbulence in a two-dimensional superfluid|volume=365 |issue=6447|pages=1267–1271 |doi=10.1126/science.aat5793 |pmid=31249055 |journal=Science |arxiv=1801.06952 |bibcode=2019Sci...364.1267J |s2cid=4948239 }}</ref>