This is how one poster tried to explain it to me but for people who have only taken a basic physics course in college it leaves alot wanting.(adsbygoogle = window.adsbygoogle || []).push({});

"If a system is in a pure state, and you know what the pure state is, then your knowledge of the system is complete, and all uncertainty is quantum. If we take a state to apply to an ensemble, this means that every member of the ensemble has been identically prepared and is in the same state."

I interpret this as acontrolledexperiment in a lab where all values areaccounted forand a photon is fired which has collapsed the particle. Here there is no uncertianty about actual collapse because the enviorment has been purposflley taken out of the equation yet collapse occurs.

"A proper mixed state means that you do not know exactly what the quantum state is, but only what the state is with some probability, so uncertainty is due to intrinsic quantum uncertainty, as well as your ignorance of the state. In an ensemble, this means that not all members of the ensemble have been identically prepared."

This is also conducted in a controlled lab where the enviorment has been taken out of the equation and a photon is not fired at the particle and superposition is apparent.

"An improper mixed state comes about when the entire system is in a pure state, but you restrict yourself to observing a subsystem. The improper mixed state describes the behaviour of the subsystem."

I assume the subsystem is the enviorment and when the enviorment is not isolated in a vaccum it acts like a pure state where superposition isnt present and the enviorment has apparently collapsed but since the enviorment has not been taken out of this equation in fact it is the core of an improper mixed state it is impossible to know if collapse has actually occured because the variables are not controlled. It is assumed the enviorment has collapsed the system by interacting with itself but it is uncertian because the variables are notcontrolled.

Im sure Im wrong about alot of this so thats why Im asking for help in figuring this out. Any help would be much aprecciated.

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# Pure, proper mixed, and improper mixed states in laymen's terms

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