## Some invariant biorthogonal sets with an application to coherent states

F. Bagarello, S. Triolo

We show how to construct, out of a certain basis invariant under the action of one or more unitary operators, a second biorthogonal set with similar properties. In particular, we discuss conditions for this new set to be also a basis of the Hilbert space, and we apply the procedure to coherent states. We conclude the paper considering a simple application of our construction to pseudo-hermitian quantum mechanics.

http://arxiv.org/abs/1402.0425
Mathematical Physics (math-ph)