In [[atomic physics]] and [[chemistry]], an '''atomic electron transition''' (also called an atomic transition, quantum jump, or quantum jumpleap) is an [[electron]] changing from one [[energy level]] to another within an [[atom]]<ref>Schombert, James. [http://abyss.uoregon.edu/~js/cosmo/lectures/lec08.html "Quantum physics"] University of Oregon Department of Physics</ref> or [[artificial atom]].<ref>{{Cite journal |arxiv = 1009.2969|bibcode = 2011PhRvL.106k0502V|title = Observation of Quantum Jumps in a Superconducting Artificial Atom|journal = Physical Review Letters|volume = 106|issue = 11|pages = 110502|last1 = Vijay|first1 = R|last2 = Slichter|first2 = D. H|last3 = Siddiqi|first3 = I|year = 2011|doi = 10.1103/PhysRevLett.106.110502|pmid = 21469850| s2cid=35070320 }}</ref> The time scale of a quantum jump has not been measured experimentally. However, the [[Franck–Condon principle]] binds the upper limit of this parameter to the order of attoseconds.<ref>{{Cite journal |last=de la Peña |first=L. |last2=Cetto |first2=A. M. |last3=Valdés-Hernández |first3=A. |date=2020-12-04 |title=How fast is a quantum jump? |url=https://www.sciencedirect.com/science/article/pii/S0375960120307477 |journal=Physics Letters A |volume=384 |issue=34 |pages=126880 |doi=10.1016/j.physleta.2020.126880 |issn=0375-9601|arxiv=2009.02426 }}</ref>
Electrons jumping to energy levels of smaller n emit [[electromagnetic radiation]] in the form of a photon. Electrons can also absorb passing photons, which drives a quantum jump to a level of higher n. The larger the energy separation between the electron's initial and final state, the shorter the photons' [[wavelength]].<ref name=":0" />
