On the Point Interaction for a Three-Particle System in Quantum Mechanics

G. Flamand

Chikhachev A.S.

Models of point interactions that approximate the real interactions of atomic particles in quantum mechanics are considered. In a one-point one-dimensional system, states are studied taking into account the eigenfield and a non-stationary problem is solved. The concept of a "point cluster" is introduced - a complex of charges that, at zero size, create the possibility of localization of a test particle in a region of finite size. An integral model of point interaction is proposed. States in three-dimensional two-point systems with "local isotropy" are studied.

Ş. Tunalı

Konstantin A. Makarov, V. V. Melezhik, Alexander Konstantinovich Motovilov

Alexander S. Chikhachev

Models of the pointed interactions approximately describing real interactions of nuclear particles in quantum mechanics are considered. The concept of “a dot cluster”—a complex of charges which at the zero size create possibility of localization of a trial particle in the field of the final size is entered. States in one-dimensional systems, and also in three-dimensional systems with “a local isotropy” are studied. The conditions of dot systems characterized by the nonzero, including fractional, orbital moment were studied.

Rodolfo Figari, Hamidreza Saberbaghi, Alessandro Teta

Abstract We re-investigate the entire family of many center point interaction Hamiltonians. Under the assumption of exchange symmetry with respect to the point positions, we show that a large sub-family of point interaction Hamiltonian operators does not become either singular or trivial when the positions of two or more scattering centers tend to coincide. In this sense, they appear to be renormalized by default as opposed to the point interaction Hamiltonians usually considered in the literature. Functions in their domains satisfy regularized boundary conditions which turn out to be very similar to the ones proposed recently in many-body quantum mechanics to define three-particle system Hamiltonians with contact interactions bounded from below. In the two-center case, we study the behavior of the negative eigenvalues as a function of the center distance. The result is used to analyze a formal Born–Oppenheimer approximation of a three-particle system with two heavy bosons and one light particle. We demonstrate that this simplified model describes a stable system (no ‘fall to the center’ problem is present). Furthermore, in the unitary limit, the energy spectrum is characterized by an infinite sequence of negative energy eigenvalues accumulating at zero according to the geometrical Efimov law.