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 [email protected]. To post to this group, send email to [email protected]. Visit this group at https://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/d/optout.
