Recent content by Plankton

the direction

Can i have a "mixed state" with e.g. Superposition Spin Up/Down [x,y,z]?

No problem. With --> (incoherent states) "states which can't be written as a state vectors / wave functions. You need so-called density matrices to describe them." - i have the answer i want! :wink:

I was thinking this is a superpostion of spin up/down [x,y,z]. hmmmmmm... :cry: can there only be a superpostion of e.g. spin up/down [x] but no superpostion of spin up/down [x] AND spin up/down [y] ... (...)

OK. E.g. i have an single photon or electron --> then it always can "be written as a state vectors / wave functions" & is never a mixed state. True? E.g. i have two photons, not entangled --> then this is always a mixed state?

Thank you much for you answers! Maybe i have later more questions.

Thats true! ;-) But it sounds interesting what you write and i think i understand it till here.

Hello, can someone give an example for an incoherent State --> a formula is here on page 7 : http://quantumcorrelations.weebly.com/uploads/6/6/5/5/6655648/2016_robustnessofcoherencetalk.pdf I know that coherenc is e.g. a superposition of e.g. Spin-Up and Spin-Down [z] or so... But i have no...