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2answers
460 views

Why for a spin half particle, possible outcomes of measuring spin projection along any direction are the same?

If one measures the projection of spin of a spin half particle along the x axis one will always get plus or minus half $\hbar$ Measuring it along the y axis one will always get plus or minus half ...
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1answer
232 views

Quantum Entanglement - Measuring Twice

In the answer here and on the wiki article and many other articles it is mentioned that if one of 2 entangled particles is measured their state collapses according to the Copenhagen interpretation. ...