In this work we give a mechanical (Hamiltonian) interpretation of the so called spectrality property introduced by Sklyanin and Kuznetsov in the context of Backlund transformations (BTs) for finite dimensional integrable systems. The property turns o
ut to be deeply connected with the Hamilton-Jacobi separation of variables and can lead to the explicit integration of the underlying model through the expression of the BTs. Once such construction is given, it is shown, in a simple example, that it is possible to interpret the Baxter Q operator defining the quantum BTs us the Greens function, or propagator, of the time dependent Schrodinger equation for the interpolating Hamiltonian.
