Abstract:
Using supersymmetric intertwining relations of the second order in
derivatives, we construct a two-dimensional quantum model with a complex
potential for which all energy levels and the corresponding wave functions
are obtained analytically. This model does not admit separation of variables
and can be considered a complexified version of the generalized
two-dimensional Morse model with an additional $\sinh^{-2}$ term. We prove
that the energy spectrum of the model is purely real. To our knowledge, this
is a rather rare example of a nontrivial exactly solvable model in two
dimensions. We explicitly find the symmetry operator, describe the
biorthogonal basis, and demonstrate the pseudo-Hermiticity of the Hamiltonian
of the model. The obtained wave functions are simultaneously eigenfunctions
of the symmetry operator.