Analysis of non-perturbative fluctuations in a triple-well potential

We consider the quantum tunneling phenomenon in a well-behaved triple-well potential. As required by the semiclassical approximation we take into account the quadratic fluctuations over the instanton which represents as usual the localised finite-action solution of the Euclidean equation of motion. The physical effects of the multi-instanton configurations are included in this approach. We obtain information about the energies of the ground state and the two first excited levels of the discrete spectrum at issue. (C) 2001 Elsevier Science B.V. All rights reserved.