Efecte de l'observador (física)

En física, l'efecte de l'observador és la pertorbació d'un sistema observat per l'acte d'observació.^[1]^[2] Això és sovint el resultat de la utilització d'instruments que, per necessitat, alteren l'estat d'allò que mesuren d'alguna manera. Un exemple comú és comprovar la pressió en un pneumàtic d'automòbil, que fa que una part de l'aire s'escapi, canviant així la pressió per observar-lo. De la mateixa manera, veure objectes no lluminosos requereix que la llum colpegi l'objecte per tal que reflecteixi aquesta llum. Tot i que els efectes de l'observació són sovint insignificants, fins i tot així l'objecte experimenta un canvi (que condueix a l'experiment mental del gat de Schrödinger). Aquest efecte es pot trobar en molts dominis de la física, però normalment es pot reduir a la insignificança mitjançant l'ús de diferents instruments o tècniques d'observació.

Un exemple notable de l'efecte observador es produeix en mecànica quàntica, com es demostra amb l'experiment de la doble escletxa. Els físics han descobert que l'observació de fenòmens quàntics per un detector o un instrument pot canviar els resultats mesurats d'aquest experiment. Malgrat l'efecte observador en l'experiment de doble escletxa és causat per la presència d'un detector electrònic, els resultats de l'experiment han estat interpretats per alguns per suggerir que una ment conscient pot afectar directament la realitat.^[3] No obstant això, la necessitat que l'observador sigui conscient (versus simplement existent, com un microorganisme unicel·lular) no està recolzada per la investigació científica, i s'ha assenyalat com un error de concepte arrelat en una mala comprensió de la funció d'ona quàntica $ψ$ i el procés de mesurament quàntic.^[4]^[5]^[6]

Referències

↑ Dirac, P.A.M.. The Principles of Quantum Mechanics. 4th. Oxford University Press, 1967, p. 3.
↑ «Archived copy». Arxivat de l'original el 19 agost 2019. [Consulta: 23 abril 2019].
↑ Squires, Euan J.. «4». A: The Mystery of the Quantum World. Taylor & Francis Group, 1994. ISBN 9781420050509.
↑ "Of course the introduction of the observer must not be misunderstood to imply that some kind of subjective features are to be brought into the description of nature. The observer has, rather, only the function of registering decisions, i.e., processes in space and time, and it does not matter whether the observer is an apparatus or a human being; but the registration, i.e., the transition from the "possible" to the "actual," is absolutely necessary here and cannot be omitted from the interpretation of quantum theory." - Werner Heisenberg, Physics and Philosophy, p. 137
↑ "Was the wave function waiting to jump for thousands of millions of years until a single-celled living creature appeared? Or did it have to wait a little longer for some highly qualified measurer - with a PhD?" -John Stewart Bell, 1981, Quantum Mechanics for Cosmologists. In C.J. Isham, R. Penrose and D.W. Sciama (eds.), Quantum Gravity 2: A second Oxford Symposium. Oxford: Clarendon Press, p. 611.
↑ According to standard quantum mechanics, it is a matter of complete indifference whether the experimenters stay around to watch their experiment, or instead leave the room and delegate observing to an inanimate apparatus which amplifies the microscopic events to macroscopic measurements and records them by a time-irreversible process (Bell, John. Speakable and Unspeakable in Quantum Mechanics: Collected Papers on Quantum Philosophy. Cambridge University Press, 2004, p. 170. ISBN 9780521523387. ). The measured state is not interfering with the states excluded by the measurement. As Richard Feynman put it: "Nature does not know what you are looking at, and she behaves the way she is going to behave whether you bother to take down the data or not." (Feynman, Richard. The Feynman Lectures on Physics, Vol. III. Ch 3.2: Basic Books, 2015. ISBN 9780465040834. ).

[1] Dirac, P.A.M.. The Principles of Quantum Mechanics. 4th. Oxford University Press, 1967, p. 3.

[2] «Archived copy». Arxivat de l'original el 19 agost 2019. [Consulta: 23 abril 2019].

[3] Squires, Euan J.. «4». A: The Mystery of the Quantum World. Taylor & Francis Group, 1994. ISBN 9781420050509.

[4] "Of course the introduction of the observer must not be misunderstood to imply that some kind of subjective features are to be brought into the description of nature. The observer has, rather, only the function of registering decisions, i.e., processes in space and time, and it does not matter whether the observer is an apparatus or a human being; but the registration, i.e., the transition from the "possible" to the "actual," is absolutely necessary here and cannot be omitted from the interpretation of quantum theory." - Werner Heisenberg, Physics and Philosophy, p. 137

[5] "Was the wave function waiting to jump for thousands of millions of years until a single-celled living creature appeared? Or did it have to wait a little longer for some highly qualified measurer - with a PhD?" -John Stewart Bell, 1981, Quantum Mechanics for Cosmologists. In C.J. Isham, R. Penrose and D.W. Sciama (eds.), Quantum Gravity 2: A second Oxford Symposium. Oxford: Clarendon Press, p. 611.

[6] According to standard quantum mechanics, it is a matter of complete indifference whether the experimenters stay around to watch their experiment, or instead leave the room and delegate observing to an inanimate apparatus which amplifies the microscopic events to macroscopic measurements and records them by a time-irreversible process (Bell, John. Speakable and Unspeakable in Quantum Mechanics: Collected Papers on Quantum Philosophy. Cambridge University Press, 2004, p. 170. ISBN 9780521523387. ). The measured state is not interfering with the states excluded by the measurement. As Richard Feynman put it: "Nature does not know what you are looking at, and she behaves the way she is going to behave whether you bother to take down the data or not." (Feynman, Richard. The Feynman Lectures on Physics, Vol. III. Ch 3.2: Basic Books, 2015. ISBN 9780465040834. ).

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