What exactly is a quantum state?

[quantum.cmptr]

What is a quantum state of a system? I keep hearing it, but I'm not able to fully understand what it means, especially in relation to Bose-Einstein Condensate, and the Pauli Exclusion Principle.

 

[samalkhaiat]

What is a quantum state of a system? I keep hearing it, but I'm not able to fully understand what it means, especially in relation to Bose-Einstein Condensate, and the Pauli Exclusion Principle.

Do you know what a classical state of a system is?

 

[quantum.cmptr]

No, I do not.

 

[samalkhaiat]

No, I do not.

In general, the state of physical system is a mathematical object(s) in terms of which all observable properties of the system can be calculated. In classical physics the state of the system is a point in phase space; the coordinates and the corresponding momenta. In quantum mechanics, the state of the system is a vector in an abstract vector space called the Hilbert space. In general, given the state of the physical system at some initial time, the equations of the theory tell you what the state will look like in a later time.

 

[dextercioby]

Technically, in most axiomatizations, a state is a (unit) ray, not a vector. But this mathematical subtlety is far beyond our OP's current level of understanding, as I suspect he's not even started his university studies, whatever the subject.

 

[quantum.cmptr]

I'm not even in high school (7th grade).

 

[samalkhaiat]

Technically, in most axiomatizations, a state is a (unit) ray, not a vector. But this mathematical subtlety is far beyond our OP's current level of understanding, as I suspect he's not even started his university studies, whatever the subject.

Are you "nitpicking" on me?

 

[quantum.cmptr]

Uh...