Time dependent scattering theory - cross section

tom.stoer
Science Advisor
Messages
5,774
Reaction score
174
I am looking for a realistic explanation of the double-slit experiment in terms of wave packets (instead of stationary waves). First of all this results in using the scattering cross section, i.e. the probability current (not the density). Then, I guess, there is a kind of time average. So one should end up with something like

j_\text{scatt}(x,t) \sim \text{Im}\psi^\ast\nabla\psi

calculated for a scattered wave packet

|\psi,t\rangle = U(t,t_0)\,|\psi,t_0\rangle

and an integration like

N(\Omega) \sim \int_{-T}^{+T}dt\,\int_\Omega d\Omega \, j_\text{scatt}(x,t)

to calculate the number of particles N detected in Omega on a spherical screen.

Is there a rigorous derivation of such an expression for wave packets using e.g. time-dependent scattering theory?
 
Last edited:
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