On Monday, October 14, 2024 at 1:14:00 AM UTC-6 scerir wrote:
Il 13/10/2024 12:40 CEST Alan Grayson <[email protected]> ha scritto: On Sunday, October 13, 2024 at 2:27:06 AM UTC-6 scerir wrote: It means that a system in a superposition is in one of the states defining the superposition, but we don't know which one. Brent alleged it is "exactly wrong". I'd like an argument why that's the case, if it is. Does it follow from Bell experiments? TY, AG Can we say that the observable has a DEFINITE value between two measurements? Imagine a spin-1/2 particle described by the state psi = sqrt(1/2)[(s+)_z+(s-)_z] . If the x-component of spin is measured by passing the spin-1/2 particle through a Stern-Gerlach with its field oriented along the x-axis, the particle will ALWAYS emerge 'up'. In fact (s+)_z = sqrt(1/2)[(s+)_x +(s-)_x] and (s-)_z = sqrt(1/2)[(s+)_x -(s-)_x] (where _z, _x, are the z-component and the x-component of spin) so psi = sqrt(1/2)[(s+)_z +(s-)_z] = (s+)_x. Now let us imagine that the state psi = sqrt(1/2)[(s+)_z +(s-)_z] is not a pure state but a mixture. In this case we might also think that - before measurement - the particle has a DEFINITE value, of the z-projection of the spin, let us say say [(s+)_z] OR [(s-)_z]. But, in this case, measuring the x-component of the spin, we would find 50% 'up'and 50% 'down'. But the real outcome says 100% 'up'. *Succinctly; what exactly do you think you've proven? How does it relate to the question posed on this threat? TY, AG* If ignorance interpretation means that a system in a superposition is in one of the states defining the superposition, that interpretation is wrong. *Which interpretation is correct? The one I prefer is that a superposition as a list of possible states is useful in calculating probabilities, and there is no inference or argument that the system that superposition represents, is in any of the states in the list. IOW, instead of assuming the system is all states in the list simultaneously, it is in NONE of those states. AG* -- You received this message because you are subscribed to the Google Groups "Everything List" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/everything-list/16708094-c9f4-451b-8bdc-71cede93ce70n%40googlegroups.com.
