Measurement in quantum mechanics: Difference between revisions
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In [[quantum mechanics]], '''measurement''' concerns the interaction of a macroscopic measurement apparatus with an observed quantum mechanical system, and the so-called "collapse" of the wavefunction upon measurement from a superposition of possibilities to a defined state. A review can be found in Zurek,<ref name=Zurek> | |||
{{cite journal |title=Decoherence, einselection, and the quantum origins of the classical |author=W. Hubert Zurek |journal=Rev Mod Phys |volume=vol. 75 |date=July, 2003 |pages=pp. 715 ''ff''|url=http://hubcap.clemson.edu/~daw/D_PHYS455/RevModPhys.v75p715y03.pdf}} | {{cite journal |title=Decoherence, einselection, and the quantum origins of the classical |author=W. Hubert Zurek |journal=Rev Mod Phys |volume=vol. 75 |date=July, 2003 |pages=pp. 715 ''ff''|url=http://hubcap.clemson.edu/~daw/D_PHYS455/RevModPhys.v75p715y03.pdf}} | ||
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The most famous illustration | ==Paradox== | ||
The interpretation of measurement in quantum maechanics has led to a number of puzzles. The most famous illustration is [[Quantum_mechanics#The_.22Schr.C3.B6dinger.27s_Cat.22_question|Schrödinger's cat]], in which a random quantum event like a radioactive decay is set up to kill a cat in a box. In the microscopic description, the cat is described by a superposition of "alive" and "dead" possibilities, and we have the peculiar result that we are in a state of suspense until we open the box to see what has happened.<ref name=Schrödinger> | |||
{{cite journal |title=The present situation in quantum mechanics; a translation of Schrödinger's "cat paradox paper" |author=Erwin Schrödinger (John D. Trimmer, translator) |journal=Proc American Phil Soc |volume=vol. 124 |pages=pp. 323-388 |url=http://www.tu-harburg.de/rzt/rzt/it/QM/cat.html#sect5 |date=Original published in German in ''Naturwissenschaften'' 1935}} | {{cite journal |title=The present situation in quantum mechanics; a translation of Schrödinger's "cat paradox paper" |author=Erwin Schrödinger (John D. Trimmer, translator) |journal=Proc American Phil Soc |volume=vol. 124 |pages=pp. 323-388 |url=http://www.tu-harburg.de/rzt/rzt/it/QM/cat.html#sect5 |date=Original published in German in ''Naturwissenschaften'' 1935}} | ||
Revision as of 10:48, 9 May 2011
In quantum mechanics, measurement concerns the interaction of a macroscopic measurement apparatus with an observed quantum mechanical system, and the so-called "collapse" of the wavefunction upon measurement from a superposition of possibilities to a defined state. A review can be found in Zurek,[1] and in Riggs.[2]
Paradox
The interpretation of measurement in quantum maechanics has led to a number of puzzles. The most famous illustration is Schrödinger's cat, in which a random quantum event like a radioactive decay is set up to kill a cat in a box. In the microscopic description, the cat is described by a superposition of "alive" and "dead" possibilities, and we have the peculiar result that we are in a state of suspense until we open the box to see what has happened.[3] Is this uncertainty about us (the observers), or the state of the cat?
Notes
- ↑ W. Hubert Zurek (July, 2003). "Decoherence, einselection, and the quantum origins of the classical". Rev Mod Phys vol. 75: pp. 715 ff.
- ↑ Peter J. Riggs (2009). “§2.3.1 The measurement problem”, Quantum Causality: Conceptual Issues in the Causal Theory of Quantum Mechanics. Springer, pp. 31 ff. ISBN 9048124026.
- ↑ Erwin Schrödinger (John D. Trimmer, translator) (Original published in German in Naturwissenschaften 1935). "The present situation in quantum mechanics; a translation of Schrödinger's "cat paradox paper"". Proc American Phil Soc vol. 124: pp. 323-388.