quantum mechanics - How will a particle with energy less than $V_{rm min}$ behave?

Consider e.g. the finite square well: $V = -V_o$ between $x=-a$ and $x=a$, $V=0$ elsewhere

Now for scattering states, $E$ must be $> 0$. For normalizable bound states, $E$ must be $< 0$ and $> V_{\rm min}$ (=$-V_o$ in example).

But if a particle in a lab has Energy which $< 0$ and $

And I don't know why I haven't thought about this before but what does it mean for a photon to have negative energy?

Answer

This particle with have an unphysical wave function which blows up (as can be quite easily derived). Therefore, in quantum mechanics, we do not have any particles with $E