According to the Copenhagen interpretation, particles don’t have definite properties until those properties are measured. So if A and B have definite momenta before they’re measured, then the Copenhagen interpretation is wrong and quantum physics is an incomplete description of nature. But if A and B don’t have definite momenta before they’re measured, then the very act of measuring A’s momentum must affect B instantly, in order to ensure that its momentum is equal and opposite to A’s—even if A is in New York City and B is on the Moon. And that violates locality. In short, quantum physics is
...more
Main
