Understand Quantum Resonance: What Is It?

[atomicpedals]

I'm finding that I don't really understand what a resonance, in the quantum mechanical use of the term, is. From what I get out of my texts it's related to an infinite square well potential. Is it when a particle is trapped but not bound? (I'm not even sure that last sentence makes sense in English or Physics)... So, for the sake of reading comprehension: what is a resonance?

 

[Dick]

'Trapped but not bound' is actually pretty close. A resonance is basically a temporary 'bound' state. It has a width in energy because it's not bound forever. It can decay. A broad resonance decays quickly, a sharp resonance more slowly. It's the delta(E)*delta(T)>Planck's constant thing. It's a finite well barrier that the particles can get stuck in for a while but eventually leak out.

 

[atomicpedals]

Thanks! Does this explain something like an unstable neutron capture reaction? Where a nucleus captures a neutron, becomes unstable, and then decays to a stable state.