|Quantum mechanics: is a partial discipline of physics, dealing with processes at the level of elementary particles. Here, principles which cannot be observed at the level of everyday objects are valid. The special forces and interactions that prevail within the quantum world are not to be found on the macro level. See also superposition, entanglement, uncertainty principle.|
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QM/Atom/Uniformity/Equality/Barrow: the quantization of energy is the reason why hydrogen atoms are identical.
Measurement Problem/QM/Barrow: it is about whether the quantum theory describes everything that happens in nature, including the measurement process, or not -
EPR/Barrow: Paradox: we cannot predict which the two photons will move clockwise in the decay - but if we were to go to the other end of the universe, we would know instantly because of quantum mechanics that the other photon rotates in the other direction, without having measured it - i.e. the unmeasured momentum must match reality - it must be real, because it is predictable. - Knowledge without measurement, i.e. independent of observation. - Paradox: the second photon must know the direction of the other. - Proof: Alain Aspect experiment 1982. - I 240 Barrow: in fact, no information is transmitted - VsEPR: simultaneity is a concept that depends on the observer. - E.g. three observers could be in motion relative to each other and to the experiment - one would see that the measurements of the spins are conducted simultaneously, while the others would first observe one or the other.
John Bell/QM/Non-Locality/Barrow: (60s): showed that every theory that describes EPR phenomena needs to have a non-local description if a simple arithmetic condition is satisfied - (>non-locality). - Bell Test/Uncertainty: Uncertainty is not about the coarseness of the observer - this would be a local explanation - ((s) VsBrecht) - Bell: Each correct view of nature must be non-local.
Copenhagen Interpretation/Bohr: In the traditional sense, no deeper reality can be discovered, but only a description of it. - Useless to say that the measuremenat somehow changed a deeper reality. - I 245 while the wave function is deterministic, linear, continuous and local, and does not know any determinate time direction, the measuring process is almost random, non-linear, discontinuous, non-local and non-reversible. - SchrödingerVsBohr: Schrödinger's cat: is in a mixture of dead and alive, as long as we do not look. - I 247 Wheeler: Problem: all astronomical measurements are made with radiation - so according to Bohr's Copenhagen interpretation, they would only be made alive by measuring.
Copenhagen Interpretation/Many-Worlds Interpretation/MWI/Aspect/Experiment/Barrow: the assumption of non-locality was experimentally confirmed by Aspect. The Copenhagen and the many-worlds interpretation appear to be completely incompatible, but there is the unanimous opinion that they are experimentally indistinguishable.
John D. Barrow
Warum die Welt mathematisch ist Frankfurt/M. 1996
John D. Barrow
Die Natur der Natur: Die philosophischen Ansätze der modernen Kosmologie Heidelberg 1993
John D. Barrow
Die Entdeckung des Unmöglichen. Forschung an den Grenzen des Wissens Heidelberg 2001