Is There a Disconnect Between Intuition and Mathematics in Quantum Theory?

billy_boy_999
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quote from The New Quantum Universe by Hey, Walters:

"(Feynman diagrams are) only a device to get the right answer without having to use the complicated machinery of quantum field theory. Nothing, as far as we know, actually travels backwards in time."
is that an accurate statement?

does it imply that there's a complete non-link between even the simplest intuitive qualitative descriptions of quantum theory and the mathematics of it?
 
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The statement by Hey and Walters is misleading. The Feynman diagrams are a condensed way of setting up the math. Each element in the diagram (input line, output line, exchange line, vertex) corresponds to a factor in the propagator integrand, so you can set up the math directly from the diagram.

The math will work either as the description of an antiparticle traveling forward in time or as the corresponding particle traveling backwards in time. (think positron, electron). QED doesn't say which is the case. Feynman apparently found it easy to think of particles moving backward in time, but most physicsts prefer to think in terms of antiparticles.
 
so it's a matter of aesthetics? :confused:
 
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!
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