What is bound states (in math)? From picture below, seemly, bound states is the solutions of equation, is right ? But in wiki, bound states is a physical conception, and I can't understand it. > ![enter image description here](

It is the same as the physical conception. They are solutions where $|\psi|$ drops to zero as you leave the local minimum f the potential $V$, so the particle has little chance of being far away. It is said to be bound to that minimum.