Finding the operators for time derivatives of observables

snoopies622
Messages
852
Reaction score
29
Looking through this matrix approach to the quantum harmonic oscillator,

http://blogs.physics.unsw.edu.au/jcb/wp-content/uploads/2011/08/Oscillator.pdf

especially the equations

<br /> <br /> m \hat{ \ddot { x } } = \hat { \dot {p} } = \frac {i}{\hbar} [ \hat {H} , \hat {p} ]<br /> <br />

I'm getting the impression that there's no difference between the time derivative of an operator (of an observable) and the operator representing the time derivative of that observable. That is, between <br /> <br /> \dot { \hat {x } }<br /> <br />and<br /> <br /> \hat { \dot {x} } Is this true? If so it would mean that, once I knew the position operator matrix for a one-particle system, finding the momentum operator matrix would be simply taking the time derivative of the position matrix (replacing every element of the matrix with its time derivative) and multiplying the whole thing by the mass.

Something tells me that that's too easy and this is just a notation problem in this particular essay, but then I'm new to matrix mechanics.
 
Physics news on Phys.org
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