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Quantum

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For other uses, see Quantum (disambiguation).

In physics, a quantum (pl.: quanta) is the minimum amount of any physical entity (physical property) involved in an interaction. The fundamental notion that a property can be "quantized" is referred to as "the hypothesis of quantization".[1] This means that the magnitude of the physical property can take on only discrete values consisting of integer multiples of one quantum. For example, a photon is a single quantum of light of a specific frequency (or of any other form of electromagnetic radiation). Similarly, the energy of an electron bound within an atom is quantized and can exist only in certain discrete values.[2] Atoms and matter in general are stable because electrons can exist only at discrete energy levels within an atom. Quantization is one of the foundations of the much broader physics of quantum mechanics. Quantization of energy and its influence on how energy and matter interact (quantum electrodynamics) is part of the fundamental framework for understanding and describing nature.

Origin

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German physicist and 1918 Nobel Prize for Physics recipient Max Planck (1858–1947)

The modern physics use of the word "quantum" dates to Dec. 14, 1900 when Max Planck reported his findings to the German Physical Society, showing that hypothesizing harmonic oscillators with a definite energy packages solved a long standing problem with the theory of blackbody radiation. [3]: 15 [4] In 1905 Albert Einstein suggested that radiation existed in spatially localized packets which he called "quanta of light" ("Lichtquanta").[5] Einstein was able to use this hypothesis to recast Planck's inconsistent treatment of the blackbody problem in a form that was also consistent with voltage observed in the photoelectric effect experiments work of Philipp Lenard.[3]: 23 

As a result of his analysis, Planck deduced the numerical value of h, known as the Planck constant, and reported more precise values for the unit of electrical charge and the Avogadro–Loschmidt number, the number of real molecules in a mole, to the German Physical Society.[6] After his theory was validated, Planck was awarded the Nobel Prize in Physics for his discovery in 1918. In his Nobel lecture, Planck referred to the constant as the "quantum of action".[7]

Quantization

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Main article: Quantization (physics)

While quantization was first discovered in electromagnetic radiation, it describes a fundamental aspect of energy not just restricted to photons.[8] In the attempt to bring theory into agreement with experiment, Max Planck postulated that electromagnetic energy is absorbed or emitted in discrete packets, or quanta.[9]

See also

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References

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  1. ^ Wiener, N. (1966). Differential Space, Quantum Systems, and Prediction. Cambridge, Massachusetts: The Massachusetts Institute of Technology Press
  2. ^ Rovelli, Carlo (January 2017). Reality is not what it seems: the elementary structure of things. Translated by Carnell, Simon; Segre, Erica (1st American ed.). New York, New York: Riverhead Books. pp. 109–130. ISBN 978-0-7352-1392-0.
  3. ^ a b Baggott, J. E. (2013). The quantum story: a history in 40 moments (Pbk ed.). Oxford [England]: Oxford University Press. ISBN 978-0-19-965597-7.
  4. ^ Planck, M. (1901). "Ueber die Elementarquanta der Materie und der Elektricität". Annalen der Physik (in German). 309 (3): 564–566. Bibcode:1901AnP...309..564P. doi:10.1002/andp.19013090311. Archived from the original on 2023-06-24. Retrieved 2019-09-16 – via Zenodo.
  5. ^ Einstein, A. (1905). "Über einen die Erzeugung und Verwandlung des Lichtes betreffenden heuristischen Gesichtspunkt" (PDF). Annalen der Physik (in German). 17 (6): 132–148. Bibcode:1905AnP...322..132E. doi:10.1002/andp.19053220607. Archived (PDF) from the original on 2015-09-24. Retrieved 2010-08-26.. A partial English translation Archived 2021-01-21 at the Wayback Machine is available from Wikisource.
  6. ^ Klein, Martin J. (1961). "Max Planck and the beginnings of the quantum theory". Archive for History of Exact Sciences. 1 (5): 459–479. doi:10.1007/BF00327765. S2CID 121189755.
  7. ^ "Max Planck Nobel Lecture". Archived from the original on 2023-07-14. Retrieved 2023-07-14.
  8. ^ Parker, Will (2005-02-11). "Real-World Quantum Effects Demonstrated". ScienceAGoGo. Retrieved 2023-08-20.
  9. ^ Modern Applied Physics-Tippens third edition; McGraw-Hill.

Further reading

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  • Hoffmann, Banesh (1959). The Strange story of the quantum: An account for the general reader of the growth of the ideas underlying our present atomic knowledge (2 ed.). New York: Dover. ISBN 978-0-486-20518-2. {{cite book}}: ISBN / Date incompatibility (help)
  • Mehra, Jagdish; Rechenberg, Helmut; Mehra, Jagdish; Rechenberg, Helmut (2001). The historical development of quantum theory. 4: Pt.1, the fundamental equations of quantum mechanics, 1925-1926 (1. softcover print ed.). New York Heidelberg: Springer. ISBN 978-0-387-95178-2.
  • M. Planck, A Survey of Physical Theory, transl. by R. Jones and D.H. Williams, Methuen & Co., Limited., London 1925 (Dover edition 17 May 2003, ISBN 978-0486678672) including the Nobel lecture.
  • Rodney, Brooks (14 December 2010) Fields of Color: The theory that escaped Einstein. Allegra Print & Imaging. ISBN 979-8373308427
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