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## А.С. Иоселевич, Комментарий к статье "Связанные состояния отталкивающихся адсорбированных атомов" (Письма в ЖЭТФ 113(8), 523 (2021)), Письма в ЖЭТФ, 113(12), 854-855 (2021)

In a recent paper [1] bound states of two point-like particles interacting via zero-radius potential characterized by the scattering length *a *was studied. The three-dimensional motion of particles is confined in one direction by an external potential. The Authors have demonstarted that under this condition the particles form bound state a for any sign of a, while in the absence of confinement it is formed only for a>0. This -- correct -- result was erroneously interpreted by the authors of [1] as ``formation of a bound state by two repulsing particles'' and was presented as a new, highly paradoxical, quantum effect. However, in reality this result can be readily explained in terms of elementary quantum mechanics if one bears in mind that the zero radius potentials always correspond to attracting interaction -- for either sign of a, so that the particles may never be repulsing under the considered conditions.