Ehrenfest theorem and Heisenberg quantum mechanics

luxxio
Messages
44
Reaction score
0
Wich are the differences between the theorem of ehrenfest and the Heisenberg's rappresentation of quantum mechanics?
 
Last edited:
Physics news on Phys.org
The Ehrenfest theorem states what are the equation of motion for the mean value of observables like Position and Momentum

The Heisenberg picture moves the time dependence of the system to operators instead of state vector. So it provides the equation of motions for the operators not for their mean value over a state. In Heisenberg picture there is no more need of a Schroedinger equations (for the state vector) because it is now substituted by the Heisenberg equation of motions (for the operators).
 
ruleva1983 said:
The Ehrenfest theorem states what are the equation of motion for the mean value of observables like Position and Momentum

The Heisenberg picture moves the time dependence of the system to operators instead of state vector. So it provides the equation of motions for the operators not for their mean value over a state. In Heisenberg picture there is no more need of a Schroedinger equations (for the state vector) because it is now substituted by the Heisenberg equation of motions (for the operators).

yes i know, but my question is to be intended in differrent manner. is the theorem of ehrenfest a consequence of the equation of motion of Heisenberg or they can be differents?
 
Ehrenfest theorem can be derived even without using the Heisenberg picture, but if that picture is used then the derivation is trivial. Is it an answer to your question?
 
Demystifier said:
Ehrenfest theorem can be derived even without using the Heisenberg picture, but if that picture is used then the derivation is trivial. Is it an answer to your question?
yes it is
 
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