Main Question or Discussion Point
What is known about the eigenstates of the ##\phi^4## theory in QFT? Is there an informal understanding of how these states are organized in the nonperturbative regime? For example, are there known to be any bound states in any dimensions? How does the energy of a multiparticle eigenstate (if anything like this exists) depend on its constituent particle momenta? I realize that there are probably no rigorous answers to these questions, however I would like some kind of intuition as this issue has been bothering me for years, thank you.