González-Santander de la Cruz, ClaraDomínguez-Adame Acosta, Francisco2023-06-202023-06-202011-01-170375-960110.1016/j.physleta.2010.12.013https://hdl.handle.net/20.500.14352/44664©2010 Elsevier B.V. All rights reserved. The authors thank J. M. R. Parrondo for discussions. This work was supported by MICINN (projects Mosaico and MAT2010-17180). C. G.-S. acknowledges financial support from Comunidad de Madrid and European Social Foundation.We calculate the energy levels of two particles trapped in a harmonic potential. The actual two-body potential, assumed to be spherically symmetric, is replaced by a projective operator (non-local separable potential) to determine the energy levels in a closed form. This approach overcomes the limitations of the regularized Fermi pseudopotential when the characteristic length of the two-body interaction potential is of the order of the size of the harmonic trap. In addition, we recover the results obtained with the Fermi pseudopotential when the length of the interaction is much smaller than the size of the trap.engjournal articlehttp://dx.doi.org/10.1016/j.physleta.2010.12.013http://www.sciencedirect.comopen access538.9ModelsLatticeStateFísica de materialesFísica del estado sólido2211 Física del Estado Sólido