Editing Quintessence (physics) (section)

{{Short description|Hypothetical fundamental force}}
{{About||other forms of quintessence|Quintessence (disambiguation)|theories and defunct or classical concepts named after the synonym "Aether"|Aether (disambiguation)}}
In [[physics]], '''quintessence''' is a [[hypothesis|hypothetical]] form of [[dark energy]], more precisely a [[scalar field]] minimally coupled to gravity, postulated as an explanation of the observation of an [[accelerating expansion of the universe|accelerating rate of expansion]] of the universe. The first example of this scenario was proposed by [[Bharat Ratra|Ratra]] and [[Jim Peebles|Peebles]] (1988)<ref name="RatraPeebles1988">{{cite journal|last2=Peebles |first2=L.|last1=Ratra |first1=P.
| title=Cosmological consequences of a rolling homogeneous scalar field| journal=[[Physical Review D]]
| date=1988
| volume=37
|issue=12
| pages=3406–3427
| doi=10.1103/PhysRevD.37.3406
|pmid=9958635|bibcode=1988PhRvD..37.3406R |doi-access=free
}}</ref> and [[Christof Wetterich|Wetterich]] (1988).<ref>{{Cite journal |last=Wetterich |first=C. |date=1988-06-13 |title=Cosmology and the fate of dilatation symmetry |url=https://dx.doi.org/10.1016/0550-3213%2888%2990193-9 |journal=Nuclear Physics B |language=en |volume=302 |issue=4 |pages=668–696 |doi=10.1016/0550-3213(88)90193-9 |arxiv=1711.03844 |bibcode=1988NuPhB.302..668W |s2cid=118970077 |issn=0550-3213}}</ref><ref>{{Cite journal |last=Doran |first=Michael |date=2001-10-01 |others=et al. |title=Quintessence and the Separation of Cosmic Microwave Background Peaks |url=https://iopscience.iop.org/article/10.1086/322253/fulltext/53251.text.html |journal=The Astrophysical Journal |language=en |volume=559 |issue=2 |pages=501–506 |doi= 10.1086/322253|arxiv=astro-ph/0012139 |bibcode=2001ApJ...559..501D |s2cid=119454400 |via=Iopscience}}</ref> The concept was expanded to more general types of time-varying dark energy, and the term "quintessence" was first introduced in a 1998 paper by [[Robert R. Caldwell]], Rahul Dave and [[Paul Steinhardt]].<ref name="CDS">{{cite journal |last1=Caldwell |first1=R. R. |last2=Dave |first2=R. |last3=Steinhardt |first3=P. J. |year=1998 |title=Cosmological Imprint of an Energy Component with General Equation-of-State |journal=Physical Review Letters |volume=80 |issue=8 |pages=1582–1585 |arxiv=astro-ph/9708069 |bibcode=1998PhRvL..80.1582C |doi=10.1103/PhysRevLett.80.1582 |s2cid=597168}}</ref> It has been proposed by some physicists to be a [[fifth force|fifth fundamental force]].<ref>{{cite journal |last=Carroll |first=S. M. |year=1998 |title=Quintessence and the Rest of the World: Suppressing Long-Range Interactions |journal=Physical Review Letters |volume=81 |issue=15 |pages=3067–3070 |arxiv=astro-ph/9806099 |bibcode=1998PhRvL..81.3067C |doi=10.1103/PhysRevLett.81.3067 |s2cid=14539052}}</ref><ref>{{cite web |last=Wetterich |first=C. |title=Quintessence – a fifth force from variation of the fundamental scale |url=http://www.thphys.uni-heidelberg.de/~wetterich/DEBarcelona0706.pdf |publisher=Heidelberg University}}</ref><ref>{{cite journal|url = https://cds.cern.ch/record/515241/files/0108217.pdf|title = Changing α With Time: Implications For Fifth-Force-Type Experiments And Quintessence|first1= Gia|last1= Dvali |first2=Matias|last2=  Zaldarriaga |journal = Physical Review Letters|year = 2002|volume = 88|issue = 9|pages = 091303|doi = 10.1103/PhysRevLett.88.091303|pmid = 11863992|arxiv = hep-ph/0108217|bibcode = 2002PhRvL..88i1303D|s2cid = 32730355}}</ref><ref>{{Cite journal |last1=Cicoli |first1=Michele |last2=Pedro |first2=Francisco G. |last3=Tasinato |first3=Gianmassimo |date=2012-07-23 |title=Natural Quintessence in String Theory |journal=Journal of Cosmology and Astroparticle Physics |volume=2012 |issue=7 |pages=044 |doi=10.1088/1475-7516/2012/07/044 |issn=1475-7516|arxiv=1203.6655 |bibcode=2012JCAP...07..044C |s2cid=250808223 }}</ref> Quintessence differs from the [[cosmological constant]] explanation of dark energy in that it is dynamic; that is, it changes over time, unlike the cosmological constant which, by definition, does not change. Quintessence can be either attractive or repulsive depending on the ratio of its kinetic and potential energy. Those working with this postulate believe that quintessence became repulsive about ten billion years ago, about 3.5 billion years after the [[Big Bang]].<ref>{{cite web |url = http://www.astronomytoday.com/cosmology/quintessence.html |title = Quintessence, accelerating the Universe? |first = Christopher |last = Wanjek|website = Astronomy Today}}</ref>

A group of researchers argued in 2021 that observations of the [[Hubble tension]] may imply that only quintessence models with a nonzero [[coupling constant]] are viable.<ref name="FLRW breakdown">{{cite journal |last1=Krishnan |first1=Chethan |last2=Mohayaee |first2=Roya |last3=Colgáin |first3=Eoin Ó |last4=Sheikh-Jabbari |first4=M. M. |last5=Yin |first5=Lu |title=Does Hubble Tension Signal a Breakdown in FLRW Cosmology? |journal=Classical and Quantum Gravity |date=16 September 2021 |volume=38 |issue=18 |pages=184001 |doi=10.1088/1361-6382/ac1a81 |arxiv=2105.09790 |bibcode=2021CQGra..38r4001K |s2cid=234790314 |issn=0264-9381}}</ref>