en>FrescoBot: Bot: standard sections headers and minor changes

2013-02-26T14:36:44Z

Bot: standard sections headers and minor changes

← Older revision		Revision as of 16:36, 26 February 2013
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	~~Scottie~~ is [http://~~pinterest~~.com/~~search~~/~~pins~~/?q=what~~%27s+published what~~'~~s published~~] on ~~his delivery certificate but he never ever genuinely favored~~ that ~~name~~. ~~My friends say it~~'s not ~~excellent for me but what I enjoy carrying out is executing ballet~~ and I'~~m making~~ an ~~attempt to make it a profession~~. ~~New York is where she and her husband are living and she enjoys just about every day residing there~~. ~~Since I was 18 I~~'~~ve been operating as~~ an ~~business office supervisor~~. ~~You can generally come across his web site below~~: http://~~Specialkboxing~~.~~Bravesites~~.com/<br><br>~~Also visit my web site~~: [http://~~Specialkboxing~~.~~Bravesites~~.~~com~~/ ~~sparring gloves~~]		The '''two-state vector formalism''' (TSVF) is a description of [[quantum mechanics]] in terms of a [[causality\|causal]] relation in which the present is caused by quantum states of the past and of the future taken in combination.

			==Theory==
			The two-state vector formalism is one example of a time-symmetric interpretation of quantum mechanics (see [[Minority interpretations of quantum mechanics]]). Time-symmetric interpretations of quantum mechanics were first suggested by [[Walter Schottky]] in 1921, <ref>Schottky, Walter. Das Kausalproblem der Quantentheorie als eine Grundfrage der modernen Naturforschung uberhaupt. Naturwissenschaften vol. 9, issue 25, pp. 492-496 (1921); vol. 9, issue 26, pp. 506-511 (1921); </ref> and later by several other scientists. The two-state vector formalism was first developed by [[Satosi Watanabe]]<ref>Watanabe, Satosi. "Symmetry of physical laws. Part III. Prediction and retrodiction." Reviews of Modern Physics 27.2 (1955): 179.</ref> in 1955, who named it the Double Inferential Vector Formalism (DIVF). Watanabe proposed that information given by forwards evolving [[quantum state]]s is not complete; rather, both forwards and backwards evolving quantum states are required to describe a quantum state: a first state vector that evolves from the initial conditions towards the future, and a second state vector that evolves backwards in time from future boundary conditions. Past and future measurements, taken together, provide complete information about a quantum system. Watanabe's work was later rediscovered by [[Yakir Aharonov]], [[Peter Bergmann]] and [[Joel Lebowitz]] in 1964, who later renamed it the Two-State Vector Formalism (TSVF).<ref>Yakir Aharonov, Lev Vaidman: ''Protective measurements of two-state vectors'', in: Robert Sonné Cohen, Michael Horne, John J. Stachel (eds.): ''Potentiality, Entanglement and Passion-At-A-Distance'', Quantum Mechanical Studies for A. M. Shimony, Volume Two, 1997, ISBN 978-0792344537, pp. 1–8, [http://books.google.com/books?id=DsNoIcQemTsC&pg=PA2 p. 2]</ref> Conventional [[prediction]], as well as [[retrodiction]], can be obtained formally by separating out the initial conditions (or, conversely, the final conditions) by performing sequences of coherence-destroying operations, thereby cancelling out the influence of the two state vectors.<ref>Yakir Aharonov, Peter G. Bergmann, Joel L. Lebowitz: ''Time symmetry in the quantum process of measurement'', Physical Review B., vol. 134, no. 6, pp. 1410–1416, 1964</ref>

			The ''two-state vector'' is represented by:
			{{Equation box 1
			\|indent =:
			\|equation = <math>\langle\Phi\| \ \ \ \|\Psi\rangle</math>
			\|cellpadding
			\|border
			\|border colour = #50C878
			\|background colour = #ECFCF4}}
			where the state <math>\langle\Phi\|</math> evolves backwards from the future and the state <math>\|\Psi\rangle</math> evolves forwards from the past.

			In the example of the [[double-slit experiment]], the first state vector evolves from the electron leaving its source, the second state vector evolves backwards from the final location of the electron on the detection screen, and the combination of forwards and backwards evolving state vectors determines what occurs when the electron passes the slits.

			The two-state vector formalism provides a time-symmetric description of quantum mechanics, and is constructed such as to be [[time-reversal invariance\|time-reversal invariant]].<ref>Michael Dickson: ''Non-relativistic quantum mechanics'', [[Jeremy Butterfield]], [[John Earman]] (eds.): ''Philosophy of Physics'', Handbook of the Philosophy of Science, North-Holland, Elsevier, pp. 275–416, [http://books.google.com/books?id=2oSn5I70WW0C&pg=PA327 Footnote on p. 327]</ref> It can be employed in particular for analyzing pre- and post-selected quantum systems. Building on the notion of two-state, Reznik and Aharonov constructed a time-symmetric formulation of quantum mechanics that encompasses probabilistic observables as well as nonprobabilistic weak observables.<ref>B. Reznik, and Y. Aharonov: ''Time-symmetric formulation of quantum mechanics'', Phys. Rev. A, vol. 52, no. 4, pp. 2538–2550, 1995</ref>

			==Relation to other work==

			In view of the TSVF approach, and in order to allow information to be obtained about quantum systems that are both pre- and post-selected, Yakir Aharonov, [[David Albert]] and [[Lev Vaidman]] developed the theory of [[weak measurement]]s.

			In TSVF, causality is time-symmetric; that is, the usual chain of causality is not simply reversed. Rather, TSVF combines causality both from the past (forward causation) and the future (backwards causation, or [[retrocausality]]).

			Similarly as the [[de Broglie–Bohm theory]], TSVF yields the same predictions as standard quantum mechanics.<ref>Yakir Aharonov, Lev Vaidmann: ''About position measurements which do not show the Bohmian particle position'', in: [[James T. Cushing]], Arthur Fine, Sheldon Goldstein (eds.): ''Bohmian mechanics and quantum theory: an appraisal'', Kluwer Academic Publishers, 1996, pp. 141–154, [http://books.google.com/books?id=EFrDTg3ztfEC&pg=PA141 p. 141], [http://books.google.com/books?id=EFrDTg3ztfEC&pg=PA147 147]</ref> Lev Vaidman emphasizes that TSVF fits very well with [[Hugh Everett]]'s [[many-worlds interpretation]].<ref>Yakir Aharonov, Lev Vaidman: ''The Two-State Vector Formalism of Quantum Mechanics: an Updated Review''. In: Juan Gonzalo Muga, Rafael Sala Mayato, Íñigo Egusquiza (eds.): ''Time in Quantum Mechanics'', Volume 1, Lecture Notes in Physics 734, pp. 399–447, 2nd ed., Springer, 2008, ISBN 978-3540734727, DOI 10.1007/978-3-540-73473-4_13, [http://arxiv.org/abs/quant-ph/0105101v2 arXiv:quant-ph/0105101v2] (submitted 21 May 2001, version of 10 Jun 2007) [http://books.google.com/books?id=InKru6zHQWgC&pg=PA443 p. 443]</ref>

			The two-state vector formalism has similarities with the [[transactional interpretation]] of quantum mechanics proposed by [[John G. Cramer]] in 1986.<ref>[[Avshalom Elitzur\|Avshalom C. Elitzur]], Eliahu Cohen: ''The Retrocausal Nature of Quantum Measurement Revealed by Partial and Weak Measurements'', AIP Conf. Proc. 1408: ''Quantum Retrocausation: Theory and Experiment (13–14 June 2011, San Diego, California)'', pp. 120-131, DOI http://dx.doi.org/10.1063/1.3663720 ([http://proceedings.aip.org/resource/2/apcpcs/1408/1/120_1 abstract])</ref> It shares the property of [[time symmetry]] with the [[Wheeler–Feynman absorber theory]] by [[Richard Feynman]] and [[John Archibald Wheeler]] and with the ''time–symmetric quantum mechanics'' of K. B. Wharton.

			==See also==
			*[[Satosi Watanabe]]
			*[[Yakir Aharonov]]
			*[[Weak measurement]]
			*[[Wheeler-Feynman absorber theory]]

			==References==
			{{reflist}}

			==Further reading==
			* Yakir Aharonov, Lev Vaidman: ''The Two-State Vector Formalism of Quantum Mechanics: an Updated Review''. In: Juan Gonzalo Muga, Rafael Sala Mayato, Íñigo Egusquiza (eds.): ''Time in Quantum Mechanics'', Volume 1, Lecture Notes in Physics, vol. 734, pp. 399–447, 2nd ed., Springer, 2008, ISBN 978-3540734727, DOI 10.1007/978-3-540-73473-4_13, [http://arxiv.org/abs/quant-ph/0105101v2 arXiv:quant-ph/0105101v2] (submitted 21 May 2001, version of 10 Jun 2007)
			* Lev Vaidman: ''The Two-State Vector Formalism'', [http://arxiv.org/abs/0706.1347v1 arXiv:0706.1347v1] (submitted 10 Jun 2007)
			* Lev Vaidman: ''Backward Evolving Quantum States'', Journal of Physics A: Mathematical and Theoretical, vol. 40, no. 12, pp. 3275 ff., DOI 10.1088/1751-8113/40/12/S23 [http://arxiv.org/abs/quant-ph/0606208v1 arXiv:quant-ph/0606208v1] (submitted 25 June 2006)
			* Yakir Aharonov, Eyal Y. Gruss: ''Two-time interpretation of quantum mechanics'', [http://arxiv.org/abs/quant-ph/0507269v1 arXiv:quant-ph/0507269v1] (submitted 28 July 2005)
			* Eyal Gruss: ''A Suggestion for a Teleological Interpretation of Quantum Mechanics'', [http://arxiv.org/abs/quant-ph/0006070v2 arXiv:quant-ph/0006070v2] (submitted 14 June 2000, version of 4 August 2000)
			* Yakir Aharonov, Lev Vaidman: ''Complete description of a quantum system at a given time'', Journal of Physics A: Mathematical and General Volume 24 Number 10, pp. 2315 ff., 1991, DOI 10.1088/0305-4470/24/10/018 ([http://iopscience.iop.org/0305-4470/24/10/018 abstract])
			* Yakir Aharonov, David Albert, Lev Vaidman: ''How the result of a measurement of a component of the spin of a spin-1/2 particle can turn out to be 100'', Phys. Rev. Lett. 60, pp. 1351–1354, 1988 ([http://prl.aps.org/abstract/PRL/v60/i14/p1351_1 abstract])
			* Yakir Aharonov, Peter G. Bergmann, Joel L. Lebowitz: ''Time symmetry in the quantum process of measurement'', Physical Review B., vol. 134, no. 6, pp. 1410–1416, 1964

			[[Category:Causality]]
			[[Category:Quantum mechanics]]

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2012-04-14T19:41:53Z

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Scottie is [http://pinterest.com/search/pins/?q=what%27s+published what's published] on his delivery certificate but he never ever genuinely favored that name. My friends say it's not excellent for me but what I enjoy carrying out is executing ballet and I'm making an attempt to make it a profession. New York is where she and her husband are living and she enjoys just about every day residing there. Since I was 18 I've been operating as an business office supervisor. You can generally come across his web site below: http://Specialkboxing.Bravesites.com/<br><br>Also visit my web site: [http://Specialkboxing.Bravesites.com/ sparring gloves]

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en>Michael Hardy: /* Formulation */