Bound state

<aside> ⚠️ In quantum physics, a bound state is a quantum state of a particle subject to a potential such that the particle has a tendency to remain localized in one or more regions of space. In relativistic quantum field theory, a stable bound state of n particles with masses $\{m_k\}_{k=1}^n$ corresponds to a pole in the S-matrix with a center-of-mass energy less than$\sum_km_k$. An unstable bound state shows up as a pole with a complex center-of-mass energy.

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Example

• "quasi-bound states”

  • Rydberg atom

    Rydberg atom

property

• $\psi(x)|_{x\rightarrow\pm\infty}\rightarrow0$