When1: 1932
Who: Ettore Majorana [Majorana, Ettore]
What: physicist
Where: Italy
Detail: He lived 1906 to 1938 and showed how Riemann sphere can designate n - 1 independent unordered spatial spin directions for a particle with spin 0.5 * n, with no opposite directions [1932]. Quantum mechanically, particle spins about many spatial axes simultaneously. However, large particle collections spin around one axis. It is not clear how collective spin is sum of particle spins and thus depends on wavefunction superpositions. Only wavefunction reduction eliminates other possibilities.
Physical Sciences>Physics>History>Atomic Physics
5-Physics-History-Atomic Physics
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Date Modified: 2022.0224