Angular momentum - integer or half-integer

paweld
Messages
253
Reaction score
0
Let J be total angular momentum, L - orbital angular momentum and S - intristic momentum (spin). Squares of these operators have appropriate eigenvalues j(j+1), l(l+1), s(s+1). Which of these numbers j,l,s should be integer. I know that spin can have half-integer values. But probably orbital or total momentum values should be integer. Thanks for answer.
 
Physics news on Phys.org
The orbital momentum value must be integer. It results from the wave function one-valuedness.
The total momentum value can be half-integer.
 
j and s can both be half integer. j is one of the numbers that labels a particle species. The s of a specific particle can only change by integer amounts, and since the lowest possible value of s is always -j and the highest always +j, this means that j must be integer or half integer.

Examples: When j=1, s can take the values -1,0,1. When j=1/2, s can take the values -1/2,1/2.
 
Insights auto threads is broken atm, so I'm manually creating these for new Insight articles. Towards the end of the first lecture for the Qiskit Global Summer School 2025, Foundations of Quantum Mechanics, Olivia Lanes (Global Lead, Content and Education IBM) stated... Source: https://www.physicsforums.com/insights/quantum-entanglement-is-a-kinematic-fact-not-a-dynamical-effect/ by @RUTA
If we release an electron around a positively charged sphere, the initial state of electron is a linear combination of Hydrogen-like states. According to quantum mechanics, evolution of time would not change this initial state because the potential is time independent. However, classically we expect the electron to collide with the sphere. So, it seems that the quantum and classics predict different behaviours!
Back
Top