〈 Berger | Dillon 〉

What is an “observable” or should I just say “observer” in QM?

Another good question. An observable is simply a dynamical value that one can measure (e.g. momentum, position, spin, angular momentum etc.). These are represented by hermitian operators because that enforces that the eigenvalues (what we measure) always be real

And an "observer" in QM is nothing spooky. At the end of the day it means to measure an observable. So a really tiny slit that confines a photon to a small region of space can be said to have measured its location

Understood. Does it have anything to do with consciousness affecting the result ?

No, that's a common misconception. People just tend to associate the word "observation" with consciousness, but for all intents and purposes "observation" is simply an interaction with the system. *That* is what causes wave function collapse.

Thanks. Apparently when I say this to some, they tend to say I’m wrong. I even have a fellow physics major who thinks that wave function collapse has to do with “observation” in the sense of consciousness. He’s too smug for me to correct tho.

Ask him to point to where in the equations the "consciousness variable" is that accounts for this.. when he can't ask him how he can say it's a part of the mathematical model

Great point, but I see both sides and to rule out consciousness playing a role definitevely would be claiming you've resolved the many conflicting but valid interpretations of quantum mechanics. Ie. The Von Neumann-Wigner interpretation posits a need for consciousness.