Large Order Behaviour of Perturbation Expansions

The following sections are included:

• Introductory Remarks

• Cosine Potential: Large Order Behaviour

• Cosine Potential: Complex Eigenvalues

  • The decaying ground state

  • Decaying excited states

  • Relating the level splitting to imaginary E

  • Recalculation of large order behaviour

• Cosine Potential: A Different Calculation

• Anharmonic Oscillators

  • The inverted double well

  • The double well

• General Remarks