Editing Quantum chaos (section)

== History ==
[[File:3dbifmap.jpg|300px|left|thumb|Experimental recurrence spectra of lithium in an electric field showing birth of quantum recurrences corresponding to [[Bifurcation theory|bifurcations]] of classical orbits.<ref>{{Cite journal |last1=Courtney |first1=Michael |last2=Jiao |first2=Hong |last3=Spellmeyer |first3=Neal |last4=Kleppner |first4=Daniel |last5=Gao |first5=J. |last6=Delos |first6=J. B. |date=February 1995 |title=Closed Orbit Bifurcations in Continuum Stark Spectra |journal=Physical Review Letters |language=en |volume=74 |issue=9 |pages=1538–1541 |doi=10.1103/PhysRevLett.74.1538 |pmid=10059054 |bibcode=1995PhRvL..74.1538C |issn=0031-9007}}</ref>]]

During the first half of the twentieth century, chaotic behavior in mechanics was recognized (as in the [[three-body problem]] in [[celestial mechanics]]), but not well understood. The foundations of modern quantum mechanics were laid in that period, essentially leaving aside the issue of the quantum-classical correspondence in systems whose classical limit exhibit chaos.