On Thursday, November 15, 2018 at 8:04:53 AM UTC, scerir wrote: > > 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'. >
*Why? Won't the measured value be along the x axis in both directions, in effect Up or Dn? AG* 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 that psi = sqrt(1/2)[(s+)_z +(s-)_z] = (s+)_x. (pure state, not > mixture state).. > > AGrayson2000 asked "If a system is in a superposition of states, whatever > value measured, will be repeated if the same system is repeatedly > measured. But what happens if the system is in a mixed state?" > > Does Everett's "relative state interpretation" show how to interpret a > real superposition (like the above, in which the particle will always > emerge 'up') and how to interpret a mixture (in which the particle will > emerge 50% 'up' or 50% 'down')? > -- 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 everything-list+unsubscr...@googlegroups.com. To post to this group, send email to everything-list@googlegroups.com. Visit this group at https://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/d/optout.
