> Il 15 novembre 2018 alle 14.29 agrayson2...@gmail.com ha scritto: > > > > 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 >
"Hence we must conclude that the system described by the |+>x state is not the same as a mixture of atoms in the |+> and !-> states. This means that each atom in the beam is in a state that itself is a combination of the |+> and |-> states. A superposition state is often called a coherent superposition since the relative phase of the two terms is important." .see pages 18-19 here https://tinyurl.com/ybm56whu > > > > > > > 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 > mailto:everything-list+unsubscr...@googlegroups.com . > To post to this group, send email to email@example.com > mailto:firstname.lastname@example.org . > Visit this group at https://groups.google.com/group/everything-list. > For more options, visit https://groups.google.com/d/optout. > -- 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 email@example.com. Visit this group at https://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/d/optout.