Physical states are characterised uniquely by their pole positions and the corresponding residues. Accordingly, in those parameters also the nature of the states should be encoded. For bound states (poles on the real s-axis below the lowest threshold on the physical sheet) there is an established criterion formulated originally by Weinberg in the 1960s, which allows one to estimate the amount of compact and molecular components in a given state. We demonstrate in this paper that this criterion can be straightforwardly extended to shallow virtual states (poles on the real s-axis below the lowest threshold on the unphysical sheet) which should be classified as molecular. We argue that predominantly non-molecular or compact states exist either as bound states or as resonances (poles on the unphysical sheet off the real energy axis) but not as virtual states. We also discuss the limitations of the mentioned classification scheme.

物理状态的唯一特征是其极点位置和相应的残基。因此，在那些参数中，状态的性质也应被编码。对于束缚态（实在的s轴上的极点低于物理图纸上的最低阈值），存在一个由Weinberg最初在1960年代制定的标准，该标准允许人们估算给定状态下的致密物和分子成分的数量。我们在本文中证明，该准则可以直接扩展到浅虚拟状态（实数极点上的极点）。-轴低于非物理层的最低阈值），应将其归类为分子。我们认为，主要是非分​​子状态或紧密状态以束缚状态或共振（非物理表面上远离真实能量轴的极点）形式存在，但不以虚拟状态形式存在。我们还将讨论上述分类方案的局限性。