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[[Quantum mechanics]] says that there is a fundamental uncertainty in nature due to the [[Heisenberg uncertainty principle]]. It is not just that we are only able to measure a particle's position, for example, to a limited accuracy, but the particle itself does not have a precise position. Local hidden variable theories propose that particles do in fact have precise position, but observers have a limited precision available to them.

[[Quantum mechanics]] says that there is a fundamental uncertainty in nature due to the [[Heisenberg uncertainty principle]]. It is not just that we are only able to measure a particle's position, for example, to a limited accuracy, but the particle itself does not have a precise position. Local hidden variable theories propose that particles do in fact have precise position, but observers have a limited precision available to them.

At first sight, it appears that these two theories are indistinguishable from each other, but this is not true. In 1964, John Bell published his famous Bell's theorem, which showed that it local hidden variable theories and [[quantum mechanics]] do make different predictions. Hence it is in fact possible to perform am experiment to distinguish which theory is correct. Experiments have shown that [[quantum mechanics]] is in fact correct, and that the entangled particles do "communicate" faster than [[speed of light]]. However, non-local hidden variable theories are still possible. These theories do not have the requirement of locality, which prevents faster than light communication.

At first sight, it appears that these two theories are indistinguishable from each other, but this is not true. In 1964, John Bell published his famous Bell's theorem, which showed that it local hidden variable theories and [[quantum mechanics]] do make different predictions. Hence it is in fact possible to perform an experiment to distinguish which theory is correct. Experiments have shown that [[quantum mechanics]] is in fact correct, and that the entangled particles do "communicate" faster than [[speed of light]]. However, non-local hidden variable theories are still possible. These theories do not have the requirement of locality, which prevents faster than light communication.

== See also ==

== See also ==