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Johnjbarton (talk | contribs) →Strong force phase transition: No source here says strong force phase transition, but many refs use QCD or quark-hadron |
Johnjbarton (talk | contribs) →Character: add a paragraph + ref to connect to liquid/solid and curie temperature transitions. |
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== Character ==
The [[Standard model]] of particle physics, parameterized by values measured in laboratories, can be used to predict the nature of cosmic phase transitions.<ref name=Manzudar-2019>{{Cite journal |last=Mazumdar |first=Anupam |last2=White |first2=Graham |date=2019-06-25 |title=Review of cosmic phase transitions: their significance and experimental signatures |journal=Reports on Progress in Physics |volume=82 |issue=7 |pages=076901 |doi=10.1088/1361-6633/ab1f55 |issn=0034-4885|arxiv=1811.01948 }}</ref> A system in the ground state at a high temperature changes as the temperature drops due to expansion of the universe. A new ground state may become favorable and a transition between the states is a phase transition.<ref name=Manzudar-2019/>{{rp|9}}
A phase transition can be related to a difference in symmetry between the two states. For example liquid is isotropic but solid water, [[ice]], has directions with different properties. The two states have different energy: ice has less energy than liquid water.
A system like an iron bar being cooled below its [[Curie temperature]] can have two states at the same lower energy with electron magnetic moments aligned in opposite directions. Above the Curie temperature the bar is not magnetic corresponding to isotropic moments; below its magnetic properties have two different values corresponding to inversion symmetry. The process is called [[spontaneous symmetry breaking]].<ref name="Chow-2008">{{Cite book |last=Chow |first=Tai L. |url=https://www.worldcat.org/title/166358163 |title=Gravity, black holes, and the very early universe: an introduction to general relativity and cosmology |date=2008 |publisher=Springer |isbn=978-0-387-73629-7 |___location=New York |oclc=166358163}}</ref>{{rp|178}}
=== Transition order ===
Phase transitions can be categorised by their [[Phase Transition#Classifications|order]]. Transitions which are first order proceed via [[False_vacuum_decay#Bubble_nucleation|bubble nucleation]] and release [[latent heat]] as the bubbles expand.
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