ruveyn wrote:
You cant. Einstein's theory is a local theory and the failure of the Bell Inequalities shows that the world is non-local. General Theory of Relativity is not compatible with quantum theory in any form. In quantum theory, the Bell Inequalities fail.
ruveyn
No, the Bell Inequalities show that the world is non-local and counterfactual definite, or local and counterfactual indefinite.
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Counterfactual definiteness is a basic assumption, which, together with locality, leads to Bell inequalities. In their derivation it is explicitly assumed that every possible measurement, even if not performed, would have yielded a single definite result. Bell's Theorem actually proves that every quantum theory must violate either locality or CFD.
Which has led some to propose:
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If the hidden variables can communicate with each other faster than light, Bell's inequality can easily be violated. Once one particle is measured, it can communicate the necessary correlations to the other particle. Since in relativity the notion of simultaneity is not absolute, this is unattractive. One idea is to replace instantaneous communication with a process which travels backwards in time along the past Light cone. This is the idea behind a transactional interpretation of quantum mechanics, which interprets the statistical emergence of a quantum history as a gradual coming to agreement between histories that go both forward and backward in time[17].
There are these:
http://en.wikipedia.org/wiki/Local_hidd ... ble_theoryWhich is prevented by Bell.
Then:
http://en.wikipedia.org/wiki/Local_realismWhich is violated by quantum entanglement.
So you must either give up locality in some sense, or realism.
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Quantum indeterminacy is the apparent necessary incompleteness in the description of a physical system, that has become one of the characteristics of the standard description of quantum physics. Prior to quantum physics, it was thought that (a) a physical system had a determinate state which uniquely determined all the values of its measurable properties, and conversely (b) the values of its measurable properties uniquely determined the state. Albert Einstein may have been the first person to carefully point out the radical effect the new quantum physics would have on our notion of physical state.[1]
Quantum indeterminacy can be quantitatively characterized by a probability distribution on the set of outcomes of measurements of an observable. The distribution is uniquely determined by the system state, and moreover quantum mechanics provides a recipe for calculating this probability distribution.
Indeterminacy in measurement was not an innovation of quantum mechanics, since it had been established early on by experimentalists that errors in measurement may lead to indeterminate outcomes. However, by the later half of the eighteenth century, measurement errors were well understood and it was known that they could either be reduced by better equipment or accounted for by statistical error models. In quantum mechanics, however, indeterminacy is of a much more fundamental nature, having nothing to do with errors or disturbance.
Counterfactual Indefiniteness can be exchanged for Non-locality in various forms, but it is unsatisfying either way as it is presented currently.
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However, Einstein did believe that quantum state cannot be a complete description of a physical system and, it is commonly thought, never came to terms with quantum mechanics. In fact, Einstein, Boris Podolsky and Nathan Rosen did show that if quantum mechanics is correct, then the classical view of how the real world works (at least after special relativity) is no longer tenable. This view included the following two ideas:
1. A measurable property of a physical system whose value can be predicted with certainty is actually an element of reality (this was the terminology used by EPR).
2. Effects of local actions have a finite propagation speed.
This failure of the classical view was one of the conclusions of the EPR thought experiment in which two remotely located observers, now commonly referred to as Alice and Bob, perform independent measurements of spin on a pair of electrons, prepared at a source in a special state called a spin singlet state. It was a conclusion of EPR, using the formal apparatus of quantum theory, that once Alice measured spin in the x direction, Bob's measurement in the x direction was determined with certainty, whereas immediately before Alice's measurement Bob's outcome was only statistically determined. From this it follows that either value of spin in the x direction is not an element of reality or that the effect of Alice's measurement has infinite speed of propagation.
I am proposing something besides those two options, saying neither that the value didn't exist til observed, nor that it influenced the other observer instantaneously.
Bell himself overlooked this.
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The only alternative to quantum probabilities, superpositions of states, collapse of the wave function, and spooky action at a distance, is that everything is superdetermined. For me it is a dilemma. I think it is a deep dilemma, and the resolution of it will not be trivial; it will require a substantial change in the way we look at things.
I am saying that when Alice observes the state at her detector, it changes the state of the pair when they were first entangled in the past, altering the result at Bob's detector accordingly.
This effect doesn't result from information propagating across a spatial distance faster than light, it results from the electrons or photons involved interacting with the period between entanglement and observation as thought it were simultaneous. Adjusting causality without removing locality OR counterfactual definiteness in the fullest sense.
More like a redrafting of what the CFD version observed would be.
06 Dec 2009, 3:12 am
I will enjoy catching up. (the game being knowledge of physics. not much of a game, but to me it's supremely fun.)
