In 1935 Albert Einstein, Boris Podolsky and Nathan Rosen (EPR) published a paper debating whether quantum mechanics could be considered a complete theory of Level 0.
The issue concerned the fact that a measurement performed on a portion of a quantum system can propagate instantaneously (Copenhagen interpretation) an effect on the result of another measure, then run to another part of the same quantum system, regardless of the distance separating the two sides. This effect is known as "instantaneous action at a distance" and is incompatible with the basic postulate of relativity, which considers the speed of light the limit at which can travel any kind of information.
The EPR paradox is actually a physical effect, the interpretation of which has the paradoxical aspects in the following sense: if a quantum system we assume some real weak and general conditions which must be reasonably true for any theory that describes physical reality without contradicting relativity (we refer to them as "realism", "location" and "completeness"), then we arrive at a contradiction. However it is noteworthy that quantum mechanics itself is not inherently contradictory, it does not appear to contradict relativity.
Five months later, Niels Bohr, one of the fathers of quantum mechanics, answered the argument of EPR with an article titled the same way. In the original EPR paper was not actually proposed any experiment. It has been David Bohm, in 1951, to propose a reformulation of the paradox in terms more easily provable experimentally.
The thought experiment devised by Bohm considerations of EPR can be described as follows: suppose that two atoms divide from a molecule and travel in opposite directions at the speed of light. A property of atoms or particles in general, is a quantum state, or quantum number, called "spin", which should represent the classically rotation of the atom upon itself. The spin state can be +1, or "on" or -1, or "down", as the two possible directions of rotation, and is a relatively easy measured it with precision. Since the original molecule that generated the atoms did not have spin, for spin conservation if an atom has spin +1, then necessarily the other has -1. The problem, quite different from billiard balls in classical physics, is that spin state is not really defined until it is actually measured, otherwise for both atoms is undefined.
Suppose then that after 10 years, when the two atoms are within 20 light years away, we provide a measure of spin on an atom, and then automatically sets up the state. The question of EPR is: how does the other atom instantly arise in the opposite state?
The paradox of E-P-R is directly related all'quantum entanglement or quantum correlation, a quantum phenomenon with no classical analog, in which each quantum state of a set of two or more physical systems depends on the states of each system in the combination, although these systems are spatially separated. The term is sometimes rendered as 'non-separability' as an entangled state implies the presence of correlations between observable physical quantities of the systems involved. For example, one can create a system consisting of two particles whose quantum state is such that - whatever the value of some observable property taken from one of the two particles - the corresponding value given the other particle will be opposite the first, despite the postulates of quantum mechanics that predict the outcome of such measures is impossible. Consequently in the presence of entanglement measurement performed on a system seems to instantly influence the state of another system: in fact, it is easy to show that the measurement has nothing to do, this is meaningful only in relation to the measurement result, not when the measure. There is a theorem which states that it is impossible to convey through this property information at speeds exceeding that of light. You can not exploit this property for any type of transmission, because in quantum mechanics is impossible to determine the outcome of a measure through the act of measuring.
Entanglement is a property of quantum mechanics that led Einstein and others to be dissatisfied with the theory. In 1935, formulated the EPR paradox, demonstrating, making use of Entanglement, that quantum mechanics is a non-local theory .
It is true that quantum mechanics has proven capable of producing correct experimental predictions to a precision never achieved before and that correlations associated with the phenomenon of quantum entanglement were actually observed.
From 1982 to 1999 a series of experiments, carried out by the Alain Aspect group and others, have shown that the measured correlations follow the predictions of quantum mechanics.
In a key experiment in 1997 N. Gisin et. al. of University of Geneva have separated two dual photons (twin-photons) of 27 Km., and changing the state to only one of these automatically and simultaneously changed the state of the other. Gisin explains:
Since the assumption of Big Bang at time zero all matter in the universe was collapsed into a single singularity, there are reason to believe that all particles of the universe, now, are all united by entanglement, regardless of the distance, and a change in the quantum state of any particle has a quantum-
probability correlation which effects any and every other particle or quantum entity in the universe, and vice versa. This, together with the coupling of the mass-particles with the Anderson-Higgs field and with the unrestrained probabilistic dynamics of each particle is probably the maximum example of the Indra Net perceived and described about 2600 years ago.
Suppose then that after 10 years, when the two atoms are within 20 light years away, we provide a measure of spin on an atom, and then automatically sets up the state. The question of EPR is: how does the other atom instantly arise in the opposite state?
The paradox of E-P-R is directly related all'quantum entanglement or quantum correlation, a quantum phenomenon with no classical analog, in which each quantum state of a set of two or more physical systems depends on the states of each system in the combination, although these systems are spatially separated. The term is sometimes rendered as 'non-separability' as an entangled state implies the presence of correlations between observable physical quantities of the systems involved. For example, one can create a system consisting of two particles whose quantum state is such that - whatever the value of some observable property taken from one of the two particles - the corresponding value given the other particle will be opposite the first, despite the postulates of quantum mechanics that predict the outcome of such measures is impossible. Consequently in the presence of entanglement measurement performed on a system seems to instantly influence the state of another system: in fact, it is easy to show that the measurement has nothing to do, this is meaningful only in relation to the measurement result, not when the measure. There is a theorem which states that it is impossible to convey through this property information at speeds exceeding that of light. You can not exploit this property for any type of transmission, because in quantum mechanics is impossible to determine the outcome of a measure through the act of measuring.
Entanglement is a property of quantum mechanics that led Einstein and others to be dissatisfied with the theory. In 1935, formulated the EPR paradox, demonstrating, making use of Entanglement, that quantum mechanics is a non-local theory .
It is true that quantum mechanics has proven capable of producing correct experimental predictions to a precision never achieved before and that correlations associated with the phenomenon of quantum entanglement were actually observed.
From 1982 to 1999 a series of experiments, carried out by the Alain Aspect group and others, have shown that the measured correlations follow the predictions of quantum mechanics.
In a key experiment in 1997 N. Gisin et. al. of University of Geneva have separated two dual photons (twin-photons) of 27 Km., and changing the state to only one of these automatically and simultaneously changed the state of the other. Gisin explains:
"What is fascinating is that entangled photons forms a single object. Even when the twin photons are separated geographically, if one of them is modified then the other photon is changed automatically and undergoes the same change."
Since the assumption of Big Bang at time zero all matter in the universe was collapsed into a single singularity, there are reason to believe that all particles of the universe, now, are all united by entanglement, regardless of the distance, and a change in the quantum state of any particle has a quantum-
probability correlation which effects any and every other particle or quantum entity in the universe, and vice versa. This, together with the coupling of the mass-particles with the Anderson-Higgs field and with the unrestrained probabilistic dynamics of each particle is probably the maximum example of the Indra Net perceived and described about 2600 years ago.
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