Physics:Thermalisation

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Short description: Tendency of bodies towards thermal equilibrium

In physics, thermalisation (or thermalization) is the process of physical bodies reaching thermal equilibrium through mutual interaction. In general the natural tendency of a system is towards a state of equipartition of energy and uniform temperature that maximizes the system's entropy. Thermalisation, thermal equilibrium, and temperature are therefore important fundamental concepts within statistical physics, statistical mechanics, and thermodynamics; all of which are a basis for many other specific fields of scientific understanding and engineering application.

Examples of thermalisation include:

The hypothesis, foundational to most introductory textbooks treating quantum statistical mechanics,[4] assumes that systems go to thermal equilibrium (thermalisation). The process of thermalisation erases local memory of the initial conditions. The eigenstate thermalisation hypothesis is a hypothesis about when quantum states will undergo thermalisation and why.

Not all quantum states undergo thermalisation. Some states have been discovered which do not (see below), and their reasons for not reaching thermal equilibrium are unclear (As of March 2019).

Theoretical description

The process of equilibration can be described using the H-theorem or the relaxation theorem,[5] see also entropy production.

Systems resisting thermalisation

Some such phenomena resisting the tendency to thermalize include (see, e.g., a quantum scar):[6]

  • Conventional quantum scars,[7][8][9][10] which refer to eigenstates with enhanced probability density along unstable periodic orbits much higher than one would intuitively predict from classical mechanics.
  • Perturbation-induced quantum scarring:[11][12][13][14][15] despite the similarity in appearance to conventional scarring, these scars have a novel underlying mechanism stemming from the combined effect of nearly-degenerate states and spatially localized perturbations,[11][15] and they can be employed to propagate quantum wave packets in a disordered quantum dot with high fidelity.[12]
  • Many-body quantum scars.
  • Many-body localisation (MBL),[16] quantum many-body systems retaining memory of their initial condition in local observables for arbitrary amounts of time.[17][18]

Other systems that resist thermalisation and are better understood are quantum integrable systems[19] and systems with dynamical symmetries.[20]

References

  1. ↑ "Collisions and Thermalization". http://sdpha2.ucsd.edu/coll_therm.html. 
  2. ↑ "NRC: Glossary -- Thermalization" (in en). https://www.nrc.gov/reading-rm/basic-ref/glossary/thermalization.html. 
  3. ↑ Andersson, Olof; Kemerink, Martijn (December 2020). "Enhancing Open‐Circuit Voltage in Gradient Organic Solar Cells by Rectifying Thermalization Losses" (in en). Solar RRL 4 (12): 2000400. doi:10.1002/solr.202000400. ISSN 2367-198X. https://onlinelibrary.wiley.com/doi/10.1002/solr.202000400. 
  4. ↑ Sakurai JJ. 1985. Modern Quantum Mechanics. Menlo Park, CA: Benjamin/Cummings
  5. ↑ Reid, James C.; Evans, Denis J.; Searles, Debra J. (2012-01-11). "Communication: Beyond Boltzmann's H-theorem: Demonstration of the relaxation theorem for a non-monotonic approach to equilibrium". The Journal of Chemical Physics 136 (2): 021101. doi:10.1063/1.3675847. ISSN 0021-9606. PMID 22260556. https://espace.library.uq.edu.au/view/UQ:282860/UQ282860_OA.pdf. 
  6. ↑ "Quantum Scarring Appears to Defy Universe's Push for Disorder". March 20, 2019. https://www.quantamagazine.org/quantum-scarring-appears-to-defy-universes-push-for-disorder-20190320/. 
  7. ↑ Heller, Eric J. (1984-10-15). "Bound-State Eigenfunctions of Classically Chaotic Hamiltonian Systems: Scars of Periodic Orbits". Physical Review Letters 53 (16): 1515–1518. doi:10.1103/PhysRevLett.53.1515. Bibcode: 1984PhRvL..53.1515H. https://link.aps.org/doi/10.1103/PhysRevLett.53.1515. 
  8. ↑ Kaplan, L (1999-01-01). "Scars in quantum chaotic wavefunctions" (in en). Nonlinearity 12 (2): R1–R40. doi:10.1088/0951-7715/12/2/009. ISSN 0951-7715. https://doi.org/10.1088/0951-7715/12/2/009. 
  9. ↑ Kaplan, L.; Heller, E. J. (1998-04-10). "Linear and Nonlinear Theory of Eigenfunction Scars" (in en). Annals of Physics 264 (2): 171–206. doi:10.1006/aphy.1997.5773. ISSN 0003-4916. Bibcode: 1998AnPhy.264..171K. https://www.sciencedirect.com/science/article/pii/S0003491697957730. 
  10. ↑ Heller, Eric (5 June 2018). The Semiclassical Way to Dynamics and Spectroscopy. ISBN 978-1-4008-9029-3. OCLC 1104876980. http://worldcat.org/oclc/1104876980. 
  11. ↑ 11.0 11.1 Keski-Rahkonen, J.; Ruhanen, A.; Heller, E. J.; Räsänen, E. (2019-11-21). "Quantum Lissajous Scars". Physical Review Letters 123 (21): 214101. doi:10.1103/PhysRevLett.123.214101. PMID 31809168. Bibcode: 2019PhRvL.123u4101K. https://link.aps.org/doi/10.1103/PhysRevLett.123.214101. 
  12. ↑ 12.0 12.1 Luukko, Perttu J. J.; Drury, Byron; Klales, Anna; Kaplan, Lev; Heller, Eric J.; Räsänen, Esa (2016-11-28). "Strong quantum scarring by local impurities" (in en). Scientific Reports 6 (1): 37656. doi:10.1038/srep37656. ISSN 2045-2322. PMID 27892510. Bibcode: 2016NatSR...637656L. 
  13. ↑ Keski-Rahkonen, J.; Luukko, P. J. J.; Kaplan, L.; Heller, E. J.; Räsänen, E. (2017-09-20). "Controllable quantum scars in semiconductor quantum dots". Physical Review B 96 (9): 094204. doi:10.1103/PhysRevB.96.094204. Bibcode: 2017PhRvB..96i4204K. https://link.aps.org/doi/10.1103/PhysRevB.96.094204. 
  14. ↑ Keski-Rahkonen, J; Luukko, P J J; Åberg, S; Räsänen, E (2019-01-21). "Effects of scarring on quantum chaos in disordered quantum wells" (in en). Journal of Physics: Condensed Matter 31 (10): 105301. doi:10.1088/1361-648x/aaf9fb. ISSN 0953-8984. PMID 30566927. https://doi.org/10.1088/1361-648x/aaf9fb. 
  15. ↑ 15.0 15.1 Keski-Rahkonen, Joonas (2020) (in en). Quantum Chaos in Disordered Two-Dimensional Nanostructures. Tampere University. ISBN 978-952-03-1699-0. https://trepo.tuni.fi/handle/10024/123296. 
  16. ↑ Nandkishore, Rahul; Huse, David A.; Abanin, D. A.; Serbyn, M.; Papić, Z. (2015). "Many-Body Localization and Thermalization in Quantum Statistical Mechanics". Annual Review of Condensed Matter Physics 6: 15–38. doi:10.1146/annurev-conmatphys-031214-014726. Bibcode: 2015ARCMP...6...15N. 
  17. ↑ Choi, J.-y.; Hild, S.; Zeiher, J.; Schauss, P.; Rubio-Abadal, A.; Yefsah, T.; Khemani, V.; Huse, D. A. et al. (2016). "Exploring the many-body localization transition in two dimensions". Science 352 (6293): 1547–1552. doi:10.1126/science.aaf8834. PMID 27339981. Bibcode: 2016Sci...352.1547C. 
  18. ↑ Wei, Ken Xuan; Ramanathan, Chandrasekhar; Cappellaro, Paola (2018). "Exploring Localization in Nuclear Spin Chains". Physical Review Letters 120 (7): 070501. doi:10.1103/PhysRevLett.120.070501. PMID 29542978. Bibcode: 2018PhRvL.120g0501W. 
  19. ↑ Caux, Jean-Sébastien; Essler, Fabian H. L. (2013-06-18). "Time Evolution of Local Observables After Quenching to an Integrable Model". Physical Review Letters 110 (25): 257203. doi:10.1103/PhysRevLett.110.257203. PMID 23829756. 
  20. ↑ Buča, Berislav; Tindall, Joseph; Jaksch, Dieter (2019-04-15). "Non-stationary coherent quantum many-body dynamics through dissipation" (in en). Nature Communications 10 (1): 1730. doi:10.1038/s41467-019-09757-y. ISSN 2041-1723. PMID 30988312. 




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