I don't understand why we quantize the field by defining the commutation relation.What's that mean?And what's the difference between the commutation and anticommtation?
Welcome to PF.
We quantize a field by the commutation relation because of the definition of the field.
Them's the rules.
The difference between commutation and anti-commutation is symmetry.
Have a go seeing what happens if you try to quantize a field by the anti-commutator.
If you can get a hold of Dirac's - Principles Of Quantum Machanics he uses that spproach.
Basically it turns out if you assume the algebraic properties of the classical Poisson Bracket still applies in QM you end up with the Poisson Bracket is the same as the commutator divided by i hbar: http://bolvan.ph.utexas.edu/~vadim/classes/2013s/brackets.pdf
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!
I don't know why the electrons in atoms are considered in the orbitals while they could be in sates which are superpositions of these orbitals? If electrons are in the superposition of these orbitals their energy expectation value is also constant, and the atom seems to be stable!