Abstract:
The properties of the $1/N$ expansion are investigated for the problem of an Ndimensional anharmonic oscillator with arbitrary power anharmonieity. The
first six terms in the expansion of the energies of the ground and first excited
levels are obtained in analytic form. The asymptotic behavior of the coefficients
in large orders of the $1/N$ expansion is investigated. The obtained formulas are
used to determine expressions for the first six coefficients of the standard
perturbation theory in powers of the coupling constant in the case of an $N$-dimensional potential with two degenerate minima. The asymptotic behavior of
these coefficients at high orders of perturbation theory is discussed.