Coupled instantons are introduced by generalizing the double well potential
to multiple mutually coupled wells. Physically this corresponds to the
simultaneous tunneling of multiple degrees of freedom. A system with four equal
minima is examined in detail. It has three instanton types or flavors with
distinct actions. For weak coupling and subject to there being a single large
(or small) parameter, the interactive system can be handled perturbatively. The
zero mode problem arising from time translation symmetry is handled via the
Fadeev-Popov procedure. A diagrammatic procedure allows corrections to the
fluctuation determinant to be calculated systematically. Independent instanton
contributions are summed over by extending the dilute gas approximation to
three flavors and energy splittings of the lowest four states is calculated.
All tunneling amplitudes are concisely expressed in terms of elementary
functions. While the model is possibly useful for a variety of physical
systems, an application is made here to the tunneling of a composite particle
in one dimension.

Cet article explore les excursions dans le temps et leurs implications.

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