Is Partial Quantum Collapse Possible Through Selective Measurement?

[Yoni]

Can you make a measurement that doesn't make the particle completely collapse into a single state, but partially collapse dismissing just some of the possible states?

 

[mayeraus41]

Any attempt to record the properties of a lepton results in an immediate change in the particles properties, and since it has infinite probable locations doing so would achieve nothing.

 

[DrChinese]

Can you make a measurement that doesn't make the particle completely collapse into a single state, but partially collapse dismissing just some of the possible states?

Absolutely! A graphic example would be an particle pair entangled on both momentum-position and polarization bases. A basis measurement on one of the pair will leave the other in an uncollapsed state on the other basis. This really applies to any particle anytime, but this example makes it obvious since the resulting remaining entanglement can be observed.