|
|
| Line 1: |
Line 1: |
| {{Other uses|Observer effect (disambiguation){{!}}Observer effect}}
| | Bonus: WP Twin and WP Twin Auto Backup: (link to ) While not a theme, I think this software is essential if you are maintaining your Wordpress blog or regularly create new blog sites. What I advise you do next is save the backup data file to a remote place like a CD-ROM, external disk drive if you have one or a provider such as Dropbox. The effect is to promote older posts by moving them back onto the front page and into the rss feed. For more info regarding [http://GET7.pw/wordpress_backup_plugin_682013 backup plugin] visit our web-site. If you're using Wordpress and want to make your blog a "dofollow" blog, meaning that links from your blog pass on the benefits of Google pagerank, you can install one of the many dofollow plugins available. Understanding how Word - Press works can be a challenge, but it is not too difficult when you learn more about it. <br><br> |
| {{Cleanup|date=May 2010}}
| |
|
| |
|
| In [[science]], the term '''observer effect''' refers to changes that the act of observation will make on a [[phenomenon]] being observed. This is often the result of instruments that, by necessity, alter the state of what they measure in some manner. A commonplace example is checking the pressure in an automobile tire; this is difficult to do without letting out some of the air, thus changing the pressure. This effect can be observed in many domains of physics.
| | purcase and download - WPZOOM Tribune wordpress Theme, find and use the WPZOOM Discount Code. Best of all, you can still have all the functionality that you desire when you use the Word - Press platform. Well Managed Administration The Word - Press can easily absorb the high numbers of traffic by controlling the server load to make sure that the site works properly. By purchasing Word - Press weblogs you can acquire your very own domain title and have total command of your web site. Moreover, many Word - Press themes need to be purchased and designing your own WP site can be boring. <br><br>Digital photography is a innovative effort, if you removethe stress to catch every position and viewpoint of a place, you free yourself up to be more innovative and your outcomes will be much better. The following piece of content is meant to make your choice easier and reassure you that the decision to go ahead with this conversion is requited with rich benefits:. After age 35, 18% of pregnancies will end in miscarriage. Storing write-ups in advance would have to be neccessary with the auto blogs. Purchase these from our site, or bring your own, it doesn't matter, we will still give you free installation and configuration. <br><br>You can add keywords but it is best to leave this alone. High Quality Services: These companies help you in creating high quality Word - Press websites. Enterprise, when they plan to hire Word - Press developer resources still PHP, My - SQL and watch with great expertise in codebase. Contact Infertility Clinic Providing One stop Fertility Solutions at:. OSDI, a Wordpress Development Company based on ahmedabad, India. <br><br>Millions of individuals and organizations are now successfully using this tool throughout the world. I don't want that for my visitors and I'm quite sure they don't either. The days of spending a lot of time and money to have a website built are long gone. Change the entire appearance of you blog using themes with one click. 95, and they also supply studio press discount code for their clients, coming from 10% off to 25% off upon all theme deals. |
| | |
| The observer effect on a physical process can often be reduced to insignificance by using better instruments or observation techniques.
| |
| | |
| Historically, the observer effect has been confused with the [[uncertainty principle]].<ref name="FurutaAya1">{{Citation|last=Furuta|first=Aya|title=One Thing Is Certain: Heisenberg's Uncertainty Principle Is Not Dead|journal=Scientific American|year=2012|url=http://www.scientificamerican.com/article.cfm?id=heisenbergs-uncertainty-principle-is-not-dead}}</ref><ref name="Ozawa2003">{{Citation|last=Ozawa|first=Masanao|title=Universally valid reformulation of the Heisenberg uncertainty principle on noise and disturbance in measurement|journal=Physical Review A|volume=67|year=2003|doi=10.1103/PhysRevA.67.042105|arxiv = quant-ph/0207121 |bibcode = 2003PhRvA..67d2105O|issue=4 }}</ref>
| |
| | |
| ==Particle physics==
| |
| For an [[electron]] to become detectable, a [[photon]] must first interact with it, and this interaction will change the path of that electron. It is also possible for other, less direct means of measurement to affect the electron.
| |
| | |
| ==Electronics==
| |
| In [[electronics]], [[ammeter]]s and [[voltmeter]]s are usually wired in series or parallel to the circuit, and so by their very presence affect the current or the voltage they are measuring by way of presenting an additional real or complex [[Electrical load|load]] to the circuit, thus changing the [[transfer function]] and behaviour of the circuit itself. Even a more passive device such as a [[current clamp]], which measures the wire current without coming into physical contact with the wire, affects the current through the circuit being measured because the [[mutual inductance|inductance is mutual]].
| |
| | |
| ==Thermodynamics==
| |
| In [[thermodynamics]], a standard [[mercury-in-glass thermometer]] must absorb or give up some [[thermal energy]] to record a [[temperature]], and therefore changes the temperature of the body which it is measuring.
| |
| | |
| ==Quantum mechanics==
| |
| The theoretical foundation of the concept of [[measurement in quantum mechanics]] is a contentious issue deeply connected to the many [[interpretations of quantum mechanics]]. A key topic is that of [[wave function collapse]], for which some interpretations assert that measurement causes a discontinuous change into an eigenstate of the operator associated with the quantity that was measured. More explicitly, the [[quantum superposition|superposition]] principle (ψ = Σa<sub>n</sub>ψ<sub>n</sub>) of quantum physics says that for a wave function ψ, a measurement will give a state of the quantum system of one of the m possible eigenvalues f<sub>n</sub>, n=1,2...m, of the operator <math>\hat{F}</math> which is part of the eigenfunctions ψ<sub>n</sub>, n=1,2,...n. Once we have measured the system, we know its current state and this stops it from being in one of its other states.<ref name="Quantum Theory and Pictures of Reality">B.D'Espagnat, P.Eberhard, W.Schommers, [[Franco Selleri|F.Selleri]]. ''Quantum Theory and Pictures of Reality''. Springer-Verlag, 1989, ISBN 3-540-50152-5</ref> This means that the type of measurement that we do on the system affects the end state of the system. An experimentally studied situation related to this is the [[quantum Zeno effect]], in which a quantum state would decay if left alone but does not decay because of its continuous observation. The dynamics of a quantum system under continuous observation is described by a quantum [[stochastic]] master equation known as the [[Viacheslav Belavkin|Belavkin]] equation.<ref name=Belavkin89>{{cite journal | |
| | author = V. P. Belavkin
| |
| | title = A new wave equation for a continuous non-demolition measurement
| |
| | journal = Physics Letters A
| |
| | volume = 140
| |
| | number = 7-8
| |
| | pages = 355–358
| |
| | year = 1989
| |
| | doi = 10.1016/0375-9601(89)90066-2
| |
| | arxiv = quant-ph/0512136|bibcode = 1989PhLA..140..355B }}</ref><ref name=Carmichael93>{{cite book
| |
| | author = Howard J. Carmichael
| |
| | title = An Open Systems Approach to Quantum Optics
| |
| | publisher = Springer-Verlag
| |
| | year = 1993
| |
| | location = Berlin Heidelberg New-York}}</ref><ref name=Bauer2012>{{cite techreport
| |
| | author = Michel Bauer, Denis Bernard, Tristan Benoist
| |
| | title = Iterated Stochastic Measurements
| |
| | note = To be published in J. Phys. A
| |
| | arxiv = 1210.0425}}</ref>
| |
| | |
| An important aspect of the concept of [[measurement in quantum mechanics|measurement]] has been clarified in some QM experiments where a small, complex, and non-sentient sensor proved sufficient as an "observer"—there is no need for a conscious "observer".<ref name="sciencedaily">[http://www.sciencedaily.com/releases/1998/02/980227055013.htm Science Daily]</ref>
| |
| | |
| A consequence of [[Bell's theorem]] is that measurement on one of two [[quantum entanglement|entangled]] particles can appear to have a nonlocal effect on the opposite particle. Additional problems related to [[quantum decoherence#In interpretations of quantum mechanics|decoherence]] arise when the observer too is modeled as a quantum system.
| |
| | |
| The [[uncertainty principle]] has been frequently confused with the observer effect, evidently even by its originator, [[Werner Heisenberg]].<ref name="FurutaAya1"/> The uncertainty principle in its standard form actually describes how [[accuracy and precision|precisely]] we may measure the position and momentum of a particle at the same time — if we increase the precision in measuring one quantity, we are forced to lose precision in measuring the other.<ref name="heisenberg">[[Werner Heisenberg|Heisenberg, W.]] (1930), ''Physikalische Prinzipien der Quantentheorie'', Leipzig: Hirzel English translation ''The Physical Principles of Quantum Theory''. Chicago: University of Chicago Press, 1930.</ref>
| |
| An alternative version of the uncertainty principle,<ref>{{Citation|last=Ozawa|first=Masanao|title=Universally valid reformulation of the Heisenberg uncertainty principle on noise and disturbance in measurement|journal=Physical Review A|volume=67|year=2003|doi=10.1103/PhysRevA.67.042105|arxiv = quant-ph/0207121 |bibcode = 2003PhRvA..67d2105O }}</ref> more in the spirit of an observer effect,<ref name=Belavkin92>{{cite journal | author = V. P. Belavkin | title = Quantum continual measurements and a posteriori collapse on CCR | journal = Communications in Mathematical Physics | volume = 146 | number = 3 | pages = 611–635 | year = 1992 | doi = 10.1007/BF02097018 | arxiv = math-ph/0512070|bibcode = 1992CMaPh.146..611B }}</ref> fully accounts for the disturbance the observer has on a system and the error incurred, although this is not how the term "uncertainty principle" is most commonly used in practice.
| |
| <!--Is all this commented out stuff actually helpful to anybody???
| |
| This is demonstrated in a common thought experiment using the double slit setup. Imagine a double slit experiment where quantum particles are fired towards the two slits. The quantum particles pass through the slits and hit a momentum sensor a distance of D behind the slits. The momentum sensor has the ability to be turned off and on via a pin that stops the movement of the sensor when it is hit by a quantum particle. When the pin is in place, no measurement of the momentum can take place. When the pin is removed, the sensor can recoil when struck by a quantum particle and by measuring the recoil determine from which slit the quantum particle came.
| |
| If the pin is removed and we can detect from which slit the particle came, then the wave-like passage through both slits cannot occur and no interference pattern will develop. However if we put the pin in place, and can no longer determine from which slit the particle passes through, then an interference pattern can develop.<ref name="Intro to Quantum Mechanics">A.C.Phillips. ''Introduction to Quantum Mechanics''. Wiley, 2003, ISBN:0-470-85323-9</ref> This can be taken a step further using the [[Wheeler%27s_delayed_choice_experiment|delayed choice experiment]].
| |
| | |
| This thought experiment was proved correct experimentally. The people conducting the experiment found that when the sensor was turned off, an interference pattern developed, but when it was turned on, the interference pattern was destroyed. It was even found that the level of detection could affect the result. <ref name="Which path detector">E.Buks, R.Schuster, M.Heiblum, D.Mahalu, V.Umansky (February 1998)."Dephasing in electron interference by a 'which-path' detector", ''Nature'', vol 391, pp 871–874. {{doi|10.1038/36057}}</ref>
| |
| | |
| The change of the wave function from ψ to ψ<sub>n</sub> is called the collapse of the wave function and occurs when the measurement takes place.<ref name="Intro to Quantum Mechanics" /> This collapse of the wave function is not explainable using the Copenhagen interpretation.<ref name="Quantum Theory and Pictures of Reality" /> Other explanations on why the wave function collapses have been developed such as the [[Hidden_variable_theory| hidden variable theory]]. | |
| | |
| The [[many-worlds interpretation]] posits the existence of multiple universes in which an observed system displays all possible states to all possible observers. In this model, observation of a system does not change the behavior of the system—it simply answers the question of which universe the observer is located in. In some universes, the observer would observe one result from one state of the system, and in others the observer would observe a different result from a different state of the system.<ref name="everettq2">[http://www.hedweb.com/manworld.htm#what Everett FAQ "What is many-worlds?"]</ref>-->
| |
| | |
| ==References==
| |
| {{Reflist}}
| |
| {{Use dmy dates|date=September 2011}}
| |
| * The observer effect by Massimiliano Sassoli de Bianchi http://arxiv.org/abs/1109.3536
| |
| | |
| {{DEFAULTSORT:Observer Effect (Physics)}}
| |
| [[Category:Concepts in physics]]
| |
Bonus: WP Twin and WP Twin Auto Backup: (link to ) While not a theme, I think this software is essential if you are maintaining your Wordpress blog or regularly create new blog sites. What I advise you do next is save the backup data file to a remote place like a CD-ROM, external disk drive if you have one or a provider such as Dropbox. The effect is to promote older posts by moving them back onto the front page and into the rss feed. For more info regarding backup plugin visit our web-site. If you're using Wordpress and want to make your blog a "dofollow" blog, meaning that links from your blog pass on the benefits of Google pagerank, you can install one of the many dofollow plugins available. Understanding how Word - Press works can be a challenge, but it is not too difficult when you learn more about it.
purcase and download - WPZOOM Tribune wordpress Theme, find and use the WPZOOM Discount Code. Best of all, you can still have all the functionality that you desire when you use the Word - Press platform. Well Managed Administration The Word - Press can easily absorb the high numbers of traffic by controlling the server load to make sure that the site works properly. By purchasing Word - Press weblogs you can acquire your very own domain title and have total command of your web site. Moreover, many Word - Press themes need to be purchased and designing your own WP site can be boring.
Digital photography is a innovative effort, if you removethe stress to catch every position and viewpoint of a place, you free yourself up to be more innovative and your outcomes will be much better. The following piece of content is meant to make your choice easier and reassure you that the decision to go ahead with this conversion is requited with rich benefits:. After age 35, 18% of pregnancies will end in miscarriage. Storing write-ups in advance would have to be neccessary with the auto blogs. Purchase these from our site, or bring your own, it doesn't matter, we will still give you free installation and configuration.
You can add keywords but it is best to leave this alone. High Quality Services: These companies help you in creating high quality Word - Press websites. Enterprise, when they plan to hire Word - Press developer resources still PHP, My - SQL and watch with great expertise in codebase. Contact Infertility Clinic Providing One stop Fertility Solutions at:. OSDI, a Wordpress Development Company based on ahmedabad, India.
Millions of individuals and organizations are now successfully using this tool throughout the world. I don't want that for my visitors and I'm quite sure they don't either. The days of spending a lot of time and money to have a website built are long gone. Change the entire appearance of you blog using themes with one click. 95, and they also supply studio press discount code for their clients, coming from 10% off to 25% off upon all theme deals.