Physics:Quantum scar - Revision history

WikiHarold: Remove imported red links from Quantum page

2026-05-23T23:48:23Z

Remove imported red links from Quantum page

← Older revision		Revision as of 23:48, 23 May 2026
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	== Quantum Birthmarks ==		== Quantum Birthmarks ==
	[[File:Quantum Birthmark.png\|thumb\|Figure presents two cases of the time-averaged probability density of a quantum wavepacket in the long-time limit, either launched on top of a scar (upper) or into a generic direction (lower). In both cases, the long-term distribution contains an imprint of the initial behavior, a quantum birthmark, instead of the expected uniformity associated with the classical ergodicity.]]
	A hallmark of classical ergodicity is the complete loss of memory of initial conditions, resulting from the eventual uniform exploration of phase space. In a quantum system, however, classical ergodic behavior can break down, as exemplified by the presence of quantum scars. The concept of a quantum birthmark<ref name=":11">{{cite arXiv \|eprint=2412.02982 \|last1=Graf \|first1=Anton M. \|last2=Keski-Rahkonen \|first2=Joonas \|last3=Xiao \|first3=Mingxuan \|last4=Atwood \|first4=Saul \|last5=Lu \|first5=Zhongling \|last6=Chen \|first6=Siyuan \|last7=Heller \|first7=Eric J. \|title=Birthmarks: Ergodicity Breaking Beyond Quantum Scars \|date=2024 \|class=quant-ph }}</ref> bridges the short-term effects, such as due to scarring, and the long-term predictions of random matrix theory. By extending beyond quantum scarring, quantum birthmarks offer a new paradigm for understanding the elusive quantum nature of ergodicity.		A hallmark of classical ergodicity is the complete loss of memory of initial conditions, resulting from the eventual uniform exploration of phase space. In a quantum system, however, classical ergodic behavior can break down, as exemplified by the presence of quantum scars. The concept of a quantum birthmark<ref name=":11">{{cite arXiv \|eprint=2412.02982 \|last1=Graf \|first1=Anton M. \|last2=Keski-Rahkonen \|first2=Joonas \|last3=Xiao \|first3=Mingxuan \|last4=Atwood \|first4=Saul \|last5=Lu \|first5=Zhongling \|last6=Chen \|first6=Siyuan \|last7=Heller \|first7=Eric J. \|title=Birthmarks: Ergodicity Breaking Beyond Quantum Scars \|date=2024 \|class=quant-ph }}</ref> bridges the short-term effects, such as due to scarring, and the long-term predictions of random matrix theory. By extending beyond quantum scarring, quantum birthmarks offer a new paradigm for understanding the elusive quantum nature of ergodicity.

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	==References==		==References==
	{{reflist}}		{{reflist}}

	~~[[Category:Quantum mechanics]]~~
	~~[[Category:Quantum chaos theory]]~~

	{{Sourceattribution\|Quantum scar}}		{{Sourceattribution\|Quantum scar}}

WikiHarold: Clean Quantum page image and red links

2026-05-23T23:35:37Z

Clean Quantum page image and red links

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WikiHarold: Use Quantum See also index module

2026-05-23T22:26:03Z

Use Quantum See also index module

← Older revision		Revision as of 22:26, 23 May 2026
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	== See also ==		== See also ==
			{{#invoke:PhysicsQC\|tocHeadingAndList\|Physics:Quantum basics/See also}}
	* [[Physics:Quantum ~~chaos\|Quantum chaos]]~~

	==References==		==References==

Harold: Restore Quantum article header template

2026-05-17T21:53:22Z

Restore Quantum article header template

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 {{short description|Phenomenon in quantum systems}}
 In [[Physics:Quantum mechanics|quantum mechanics]], '''quantum scarring''' is a phenomenon where the [[Physics:Quantum state|eigenstates]] of a classically [[Physics:Quantum chaos|chaotic]] quantum system have enhanced [[Density matrix|probability density]] around the paths of unstable classical periodic orbits.<ref name=":0">{{Cite journal |last=Heller |first=Eric J. |date=1984-10-15 |title=Bound-State Eigenfunctions of Classically Chaotic Hamiltonian Systems: Scars of Periodic Orbits |url=https://link.aps.org/doi/10.1103/PhysRevLett.53.1515 |journal=Physical Review Letters |volume=53 |issue=16 |pages=1515–1518 |doi=10.1103/PhysRevLett.53.1515|bibcode=1984PhRvL..53.1515H |url-access=subscription }}</ref><ref name=":1">{{Cite book |last=Heller |first=Eric Johnson |title=The semiclassical way to dynamics and spectroscopy |date=2018 |publisher=Princeton University Press |isbn=978-1-4008-9029-3 |location=Princeton |oclc=1034625177}}</ref> The instability of the periodic orbit is a decisive point that differentiates quantum scars from the more trivial observation that the probability density is enhanced in the neighborhood of stable periodic orbits. The latter can be understood as a purely classical phenomenon, a manifestation of the [[Physics:Correspondence principle|Bohr correspondence principle]], whereas in the former, quantum interference is essential. As such, scarring is both a visual example of quantum-classical correspondence, and simultaneously an example of a (local) quantum suppression of chaos.
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 On the classical side, there is no direct analogue of scars. On the quantum side, they can be interpreted as an eigenstate analogy to how short periodic orbits correct the universal random matrix theory eigenvalue statistics. Scars correspond to nonergodic states which are permitted by the quantum ergodicity theorems. In particular, scarred states provide a striking visual counterexample to the assumption that the eigenstates of a classically chaotic system would be without structure. In addition to conventional quantum scars, the field of quantum scarring has undergone its renaissance period, sparked by the discoveries of ''perturbation-induced scars'' and ''many-body scars'' that have subsequently paved the way towards emerging concepts within the field, such as ''antiscarring'' and ''quantum birthmarks''.
 == Scar theory ==

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