The Causality Problem and Tunneling: An Overview

Phymath
Messages
183
Reaction score
0
the causality problem and tunneling?
 
Physics news on Phys.org
Phymath said:
the causality problem and tunneling?

Tunelling is a quantum effect which consists in the existence of a non zero probability of that a point particle with energy E passes through a finite width potential barrier V(x)>E .

The causality of physical phenomena states that the effect cannot precede the cause.In classical dynamics,causality is questioned whenever forces that depend of the acceleration derivatives wrt to time appear.I would infer you to the analysis of the Abraham-Lorentz equation in the classical electrodynamics (can be found in Jackson...)

Daniel.
 
still unclear on the tunneling I am not fimilar with non zero probability (do u mean of being in a location?) and finte width potential Barrier
 
Phymath said:
still unclear on the tunneling I am not fimilar with non zero probability (do u mean of being in a location?) and finte width potential Barrier

Classically,the particle has no chance to penetrate that potential barrier,as its energy is less than the barrier's.But QM proves that this becomes possible (has a non zero probability (do u know what probabilities are...?)) once the system is quantized.Yes,the probability of passing through could be seen as the probability of finding the particle anywhere in the semiinfinite interval between the point at which the particle exits the potential barrier and the +infinity on the axis describing the direction of movement.I assumed the particle comes from -infinity.That's why the potential barrier must be finite,both as width and as height.If it wasn't finite along the "x" axis (if it didn't have a finite width),we would not be speaking about the tunnel effect.If it were infinitely hight,we would not speak about tunnel effect,but about "delta potential problem".

I hope it's clear.
 
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