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Topic: Hidden variables

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  hidden variables theory@Everything2.com
A hidden variables theory of quantum mechanics is one which does not take the statistical predictions of the quantum formalism as the ultimate truth about reality.
In 1932 John von Neumann produced a proof which was supposed to show that a hidden variables theory of quantum mechanics was impossible; that there couldn't possibly be a deeper layer of reality hiding behind the statistical predictions of quantum physics, that no further explanation would be possible.
They intended this as a proof of the existence of hidden variables, although thirty years later John Stewart Bell turned it around and used it as an argument for non-locality, which is the way it is most often thought of today.
www.everything2.com /index.pl?node_id=848696   (1829 words)

  Local hidden variable theory - Wikipedia, the free encyclopedia
In quantum mechanics, a local hidden variable theory is one in which distant events are assumed to have no instantaneous effect on local ones.
The local hidden variable prediction for these is not a straight line but a sine curve, similar to the quantum mechanical prediction but of only half the "visibility".
Instead the hidden variable set at the source is taken to determine only the probability of a given outcome, the actual individual outcomes being partly determined by other hidden variables local to the analyser and detector.
en.wikipedia.org /wiki/Local_hidden_variable_theory   (1780 words)

 Hidden variable theory -- Facts, Info, and Encyclopedia article   (Site not responding. Last check: 2007-11-01)
An analogy exists with opinion polling: it is not that opinions are indefinite, but only if a reasonable sample of the population has been polled does one expect the poll results, as statistics, to be in line with the trend in the population at large.
Such a theory is called a hidden variable theory.
Most physicists however are of the position that the true theory of the universe is not a hidden variable theory and that particles do not have any extra information which is not present in their quantum mechanics description.
www.absoluteastronomy.com /encyclopedia/h/hi/hidden_variable_theory.htm   (965 words)

 Publications List   (Site not responding. Last check: 2007-11-01)
Wind direction is a periodic variable and a multi-valued function for a given set of inputs; a conventional MLP fails at this task, and so we model the full periodic probability density of direction conditioned on the satellite derived inputs using a Mixture Density Network (MDN) with periodic kernel functions.
One well-known example of a hidden variable model is the mixture distribution in which the hidden variable is the discrete component label.
Latent variable models represent the probability density of data in a space of several dimensions in terms of a smaller number of latent, or hidden, variables.
research.microsoft.com /~cmbishop/publications_abs.htm   (13697 words)

 BM02. Christian Theology and the Physics, Metaphysics, and Mathematics of David Bohm
By performing certain measurements the hidden variables or contingent variables "cease to be unknown (or 'hidden')."[53] The Bohm-Bub hidden variables theory, besides reproducing the statistical predictions of quantum mechanics,[54] is intended to provide a detailed causal account of what is called the reduction of the wave packet during the process of measuring.
Thus to argue against the hidden variables theory on the basis of the uncertainty principle is to assume one's conclusion and thus is circular.
The Bohm-Bub hidden variables theory was conceived to illustrate the relevance of necessity and contingency in the field of enquiry at present treated by quantum theory;[88] for Bohm the theory was not intended to be definitive.
www.ksharpe.com /word/bm02chapter1.htm   (10360 words)

 Archive of Astronomy Questions and Answers   (Site not responding. Last check: 2007-11-01)
Hidden variables theory was developed after quantum theory made its debut in the late 1920's.
If we did have the full set of variables, or so the theory goes, the new ones would make the quantum state fully deterministic rather that fundamentally indeterminate as it now seems to be.
The new variables seem to be extremely well 'hidden' because modern quantum theory now accounts for all of the quantities that experimentally we seem to have a good handle on such as position, time, spin, charge, energy and momentum.
www.astronomycafe.net /qadir/q514.html   (712 words)

 ipedia.com: Hidden variable theory Article   (Site not responding. Last check: 2007-11-01)
In physics, a hidden variable theory is urged by a minority of physicists who argue that the statistical nature of quantum mechanics implies that it is really applicable only to ensembles of particles.
Experiments have been interpreted as showing the orthodox account to be correct, but the hope for a so-called local hidden variable theory is still very much alive [1].
The best-known hidden-variable theory, the Bohmian mechanics, of the physicist and philosopher David Bohm, created in 1952, is a non-local hidden variable theory.
www.ipedia.com /hidden_variable_theory.html   (665 words)

 Quantum Mechanics and Hidden-Variables Determinism
  Hidden variables determinism has been disproved by QM according to seemingly most people -- though in fact hidden variables determinism is fully viable and is starting to have a resurgence.
You are asserting the Copenhagenist interpretation of quantum physics (Bohr), against hidden variables interpretations (Einstein, Bohm).
A quantum physics theory that holds that the universe is possibly in-principle predictable and is timelessly deterministic (entanglement and hidden variables) is a vertical-determinism theory.
www.egodeath.com /QMHiddenVariablesDeterminism.htm   (3545 words)

 Quantum mechanics the way I see it
Logical positivism considered hidden variables metaphysical because it was thought to be impossible to operationally control them.
The general feeling that quantum mechanics should be incompatible with the existence of hidden variables may have been enhanced by Bohr's "victory" over Einstein in the (in)completeness debate, interpreted by many as defeating hidden variables.
hidden variables represented by values of quantum mechanical observables (compare the EPR elements of physical reality), considered as properties the individual objects objectively possess prior to measurement, and explaining individual measurement results found later.
www.phys.tue.nl /ktn/Wim/qm4.htm   (2391 words)

 Hidden variables and hidden time in quantum theory
The problem of hidden variables is historically connected to a gedankenexperiment proposed by Einstein, Podolsky and Rosen [1], when trying to revise some positions of quantum mechanics.
From hidden time concept view EPR - phenomenon in its essence is described in the same manner as Fig.
Hidden time signals are by themselves not the same as wave function, but they are principially able to accomplish distributed calculation of such amplitudes.
www.geocities.com /bellstheorem   (4918 words)

 Zot-Dispatch Variables
Hidden variables are input fields in a FORM that are hidden to the user of a FORM.
hidden variable allows the author of a FORM the ability to define environment variables which should be made available to be substituted into a template or placed in the default response.
If an environment variable is named in the value of a ZD-Environment variable and that environment variable is defined to the server, then its value will be available to be substituted into a template by using its name for the variable name.
www.oac.uci.edu /X/W6/forms/zot-dispatch/ZD-Variables.html   (946 words)

 Declaring Variables in FoxPro
Public variables, also known as global variables, are variables that may be used and modified by any FoxPro program and any of its sub-programs for the duration of the FoxPro session or until the variable is cleared from memory.
Variables may not be declared hidden, but variables that were previously declared as Public or Private may become hidden.
By hiding variables created in higher programs, you can enable variables of the same name to be manipulated in the current program without affecting the values of the hidden variables.
support.microsoft.com /kb/122907   (521 words)

 Summary of responses on "Learning BNs with hidden variables"
The data's expected sufficient statistics are a super-position of an exponential number of different interpretations, each associated with a different choice of hidden variable values, and any two interpretations may have opposite log-likelihood gradients that "pull" toward opposite but permutationally equivalent equilibria.
The problem worsens with "interior" hidden variables because diffusion of context increases the uncertainty in the expected sufficient statistics with each step away from the observables.
E.g., you think the variable is called Alive, but the learning algorithm settles on a set of CPTs such that the variable is in fact representing Dead.
www.mail-archive.com /uai@cs.orst.edu/msg00064.html   (1112 words)

 Physics Myths and physics facts
However, a correct consideration of the scattering geometry shows that this result is erroneous: it is the consequence of neglecting a cos- factor which describes the density of particles hitting the surface of the spherical target and provides the geometrical connection between the monodirectional incident particle beam and the spherical scattering surface.
Hidden Variables: Several experiments have been performed in the past in order to answer the question if Quantum Mechanics is complete or if its statistical and indeterministic nature is only an apparent one and some 'hidden variables' exist that would in principle enable a deterministic description.
However, the flaw with the theoretical argument is that the classical (Hidden Variable) interpretation assumes essentially a one to one correspondence between the atomic emission and the detected coincidences.
www.physicsmyths.org.uk   (8155 words)

 Hidden Variables
It fitted so perfectly with my ideas about hidden variable theory and how the universe itself hides her underlying complexity of her innermost workings away from us.
It was obviously the wierdness on the different hidden variable theories that I had been studying that was at the root of them as they played on my mind.
So, my thesis became simply a review of the literature behing hidden variable theories but, because it was so well researched and thorough, I got my PhD anyway because it was decreed that it desreved a pass for effort.
homepage.ntlworld.com /karnuvap/html/hidden_variables.html   (1018 words)

 Visitor Data - Hidden Variables and Cookies
Hidden variables provide one means for the client to hold and send state to the server.
Hidden variables are data held by the browser client and returned to the server through the GET or POST form method just as a variable that is not hidden.
In contrast to hidden variables, which only exist as long as the browser holds the HTML page, cookies are relatively long lived, stored on the client file-system.
homepages.ius.edu /RWISMAN/A348/html/Hidden.htm   (1816 words)

 Design Considerations for Gene Expression Probabilistic Graphical Models with Hidden Variables
For a 2-population mixture density problem in which the difference of means is 1 and both population variances equal 1, and the mixing proportions are 0.3 and 0.7, the Cramer-Rao lower bound on the variance of the Maximum Likelihood estimators of the means is 4,500/sqrt(N).
A PGM with two or more hidden variables creates a "patchwork quilt" of mixture densities whose parameters must be estimated by maximum likelihood through the calculations of the EM algorithm.
In the two hidden variable model proposed by Segal, et al 2001 and Friedman 2004, we filled in the Gene.GeneCluster values by doing a hierarchical clustering as a preprocessing step and assigning genes to clusters from the results.
www.iscb.org /ismb2004/posters/amadioATrider.edu_107.html   (804 words)

 Weblogs Forum - Hidden Variables
This was called the "hidden variable theory." Numerous subsequent experiments have shown that there is no hidden variable and every event really does have a probabilistic component.
We may not have hidden variables, but the universe may be interconnected in such a manner that 'exciting' one node also excits the neighbouring nodes (of course that's intuition, not a proof by any means).
It's possible that hidden variables might exist but they are not detectable and are not required to produce accurate predictions and therefore are not part of science (at this point in time.) In other words, they could exist but they are not part of our experience i.e.
www.artima.com /forums/flat.jsp?forum=106&thread=167850   (2629 words)

 Hidden Variables Quantum Theory and Divine Agency   (Site not responding. Last check: 2007-11-01)
The proposition that non-local hidden variables interpretations of quantum mechanics qualify as an appeal to supernatural agency is examined.
Hidden variables theories postulate natural, but unobservable orders of reality whose processes give rise to observable phenomena.
Various thinkers suggest that these unobservable orders might provide a means to describe divine interaction with the natural order, leading to a reconsideration of what is meant by supernatural agency.
www.utexas.edu /cola/depts/philosophy/faculty/koons/ntse/abstracts/Hall_D.html   (324 words)

 Quantum Foundations by D Hemmick: Dissertation Abstract
These theorems are often credited with proving that hidden variables are indeed `impossible', in the sense that they cannot replicate the predictions of quantum mechanics.
The second reason hidden variables are disregarded is that the most sophisticated example of a hidden variables theory---that of David Bohm---exhibits nonlocality, i.e., it can happen in this theory that the consequences of events at one place propagate to other places instantaneously.
According to Bell, these latter theorems do not imply that hidden variables interpretations are untenable, but instead that such theories must exhibit contextuality, i.e., they must allow for the dependence of measurement results on the characteristics of both measured system and measuring apparatus.
home.mchsi.com /~bellwasright/abstract.html   (696 words)

 Bohmian Mechanics
Rather, it governs the motion of the fundamental variables, the positions of the particles: In the Bohmian mechanical version of nonrelativistic quantum theory, quantum mechanics is fundamentally about the behavior of particles; the particles are described by their positions, and Bohmian mechanics prescribes how these change with time.
This demonstrates that all claims to the effect that the predictions of quantum theory are incompatible with the existence of hidden variables, with an underlying deterministic model in which quantum randomness arises from averaging over ignorance, are wrong.
The "hidden variables" model is then obtained by regarding the initial configuration of this big system as random in the usual quantum mechanical way, with distribution given by ψ
plato.stanford.edu /entries/qm-bohm   (10692 words)

 Hidden Variables in Quantum Theory: The Hidden Cultural Variables of Their Rejection
And the current difficulties and apparent impossibility in assessing experimentally the validity of hidden variables theories is not an argument either since it works equally well against the standard interpretation.
But I think the main reason why quantum mechanics was enshrouded in an orthodox and “tough” interpretation against any hidden variables interpretation was that the latter aroused the specter of determinism that was inherent to classical Newtonian physics.
For the moment, at least, some of the implicit grounds on which the physics community rejected the hidden variables hypothesis are historical and I doubt the monotheistic God would use that door.
www.miguel-montenegro.com /Hidden_cultural_variables.htm   (2634 words)

 doIsearch Users' Guide
"Hidden" form variables are form variables which are not displayed to the user, but they allow you to set the values for certain variables that can be read by the application processing your form.
These three variables should be thought of as a triplet controlling the words to be searched for, which tagged field to search in (or fulltext) and the weight to give the search term in sorting the output of the search.
Typically this will be set with a hidden form variable, but it could be set with a pull down menu if you want to give users the option of selecting alternate databases from a single form.
www.indiana.edu /~percival/docs/doIsearch_guide.html   (4781 words)

 [No title]
The premises include neither the existence of hidden variables nor counterfactual definiteness, nor any premise that effectively entails the general existence of outcomes of unperformed local measurements.
Thus these hidden-variable theorems place in no serious jeopardy the basic locality idea that a free choice made by an experimenter in one space-time region has no influence in a second region that is space-like separated from the first.
That is because the hidden variables identify instances in which the outcomes of all four of the alternative possible experiments can be considered simultaneously.
www-physics.lbl.gov /~stapp/whv.txt   (2715 words)

 Lost causes in physics, by R. F. Streater   (Site not responding. Last check: 2007-11-01)
By allowing that the random variable chosen by A to model X if B measures Y to be a different random variable from the one she chooses if Bob measures Z, one can reproduce the quantum correlations exactly.
The representation of the observables as random variables is, in each case, then an immediate consequence of Gelfand's general construction of a representation of a commutative C* sub-algebra by bounded random variables defined on the spectrum of the subalgebra.
One of von Neumann's axioms, used to exclude hidden variables in quantum mechanics, is that the sum of two observables should be an observable.
www.mth.kcl.ac.uk /~streater/lostcauses.html   (12381 words)

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