In quantum mechanics, alpha particles are generally not considered to be in a "true" bound state. An alpha particle consists of two protons and two neutrons, which are held together by the strong nuclear force. However, the strong nuclear force is a short-range force that acts within the nucleus and binds protons and neutrons together to form stable atomic nuclei.
In a strict sense, a bound state refers to a system where the constituents are permanently confined together due to their mutual interactions. Examples of bound states include electrons bound to atomic nuclei in atoms or nucleons bound together in atomic nuclei. These bound states are characterized by discrete energy levels.
On the other hand, alpha particles are more appropriately described as composite particles or clusters rather than true bound states. Although the constituent nucleons (protons and neutrons) are bound within the alpha particle, the alpha particle itself is not stable outside the context of the atomic nucleus.
When alpha particles are emitted during certain types of radioactive decay, they can be detected as individual particles, but they eventually undergo interactions and disintegrate due to their inherent instability. Therefore, alpha particles are not considered to be in a "true" bound state in the same sense as electrons in atoms or nucleons in atomic nuclei.
It's important to note that the distinction between "true" bound states and other composite particles can sometimes be subtle, and the terminology may vary depending on the specific context or interpretation. However, in the conventional understanding of quantum mechanics and nuclear physics, alpha particles are not typically regarded as particles in a "true" bound state.