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(90,061 posts)
18. Hidden variable theory
Tue Jul 5, 2016, 01:12 PM
Jul 2016

Historically, in physics, hidden variable theories were espoused by some physicists who argued that the state of a physical system, as formulated by quantum mechanics, does not give a complete description for the system; i.e., that quantum mechanics is ultimately incomplete, and that a complete theory would provide descriptive categories to account for all observable behavior and thus avoid any indeterminism. The existence of indeterminacy for some measurements is a characteristic of prevalent interpretations of quantum mechanics; moreover, bounds for indeterminacy can be expressed in a quantitative form by the Heisenberg uncertainty principle.

Albert Einstein, the most famous proponent of hidden variables, objected to the fundamentally probabilistic nature of quantum mechanics,[1] and famously declared "I am convinced God does not play dice".[2] Einstein, Podolsky, and Rosen argued that "elements of reality" (hidden variables) must be added to quantum mechanics to explain entanglement without action at a distance.[3][4] Later, Bell's theorem would suggest that local hidden variables of certain types are impossible, or that they evolve non-locally. A famous non-local theory is De Broglie–Bohm theory.


Recent developments

In August 2011, Roger Colbeck and Renato Renner published a proof that any extension of quantum mechanical theory, whether using hidden variables or otherwise, cannot provide a more accurate prediction of outcomes, assuming that observers can freely choose the measurement settings.[26] Colbeck and Renner write: "In the present work, we have ... excluded the possibility that any extension of quantum theory (not necessarily in the form of local hidden variables) can help predict the outcomes of any measurement on any quantum state. In this sense, we show the following: under the assumption that measurement settings can be chosen freely, quantum theory really is complete".

In January 2013, GianCarlo Ghirardi and Raffaele Romano described a model which, "under a different free choice assumption [...] violates [the statement by Colbeck and Renner] for almost all states of a bipartite two-level system, in a possibly experimentally testable way".[27]


Oh, how the Left loves science ... MicaelS Jul 2016 #1
Trump is "the left"? bemildred Jul 2016 #2
The article in the OP was published by a left leaning website. progressoid Jul 2016 #4
It's not a right-left issue, why muddy the water with an attack on "the left". bemildred Jul 2016 #5
I can't speak for MicaelS progressoid Jul 2016 #6
We do not push this idea. bemildred Jul 2016 #7
Thankfully, we collectively don't. progressoid Jul 2016 #8
We don't shut people up here unless they get disruptive. bemildred Jul 2016 #9
Okey Dokey. progressoid Jul 2016 #14
Please do. nt bemildred Jul 2016 #15
Philosophy of Physics kristopher Jul 2016 #10
+1. nt bemildred Jul 2016 #11
Guilty as charged. Wait, what's this... progressoid Jul 2016 #12
Another sad example of your non-ability to engage with reason. kristopher Jul 2016 #13
I agree. I engaged in character assassination. progressoid Jul 2016 #16
You are incapable of rational discussion kristopher Jul 2016 #17
Perhaps you should take this up with the authors of the Wiki entries and Vandana Shiva herself. progressoid Jul 2016 #19
No, the problem lies with your falsehoods and misrepresentations, kristopher Jul 2016 #20
Well that's ironic. progressoid Jul 2016 #21
Poor progressoid... kristopher Jul 2016 #22
Uh oh. Resorting to ad hominem attacks? progressoid Jul 2016 #23
That is clearly the domain you prefer... kristopher Jul 2016 #24
So are you going to post your curriculum vitae? progressoid Jul 2016 #25
Hidden variable theory bemildred Jul 2016 #18
The OP is by a long-time anti-GMO propagandist. It's ludicrous. HuckleB Jul 2016 #29
Vandana Shiva. Crackpot, opportunist, fraud and luddite. progressoid Jul 2016 #3
Corporate GMO & Chem Trolls are destroying the credibility of science Scientific Jul 2016 #26
IS anti-GMO the new anti-vax? HassleCat Jul 2016 #27
Yeah. progressoid Jul 2016 #28
Exactly. HuckleB Jul 2016 #30
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