Calculate Spin Operators from a Spinor

[eyalleiz]

can someone explain to me that is a spinor and how do I calculate the spin operators from it?
for ex. (from homeword)
the spinor is (|a|*e^(i*alpha), |b|*e^(i*beta))

 

[Manilzin]

A spinor is an egienstate of the spin operator, which, in the case of spin 1/2-particles, can be represented as a two-component vector. You don't construct the spin operator from the spinors - you can construct a representation of the operator by finding its matrix elements, or by finding its eigenvalues.

Assuming you are using the standard quantization procedure, the spinor you gave is represented as an eigenspinor to the z-component of the spin operator.

 

[eyalleiz]

thank you