For the present, hermitian operators only play chief role in theoretical physics. Being long neglected, non-hermitian operators however are supposed to partake a certain role in physical theories. Annihilation or creation operators are clearly non-hermitian. Hitherto we are interested in eigenfunction expansions over some real interval. In the folllowing, we consider eigenfunction expansions over some closed curve in the complex plane.
No takes yet. Share an insight, caveat, or question.
Giiti Iwata (1951) studied this question.
Synapse has enriched 5 related papers. Consider them for comparative context: