ABSTRACT
This chapter deals with dimensionality reduction in the frequency domain. The advantage of quantum-mechanical signal processing is in a direct reliance upon the dynamics of the examined system whose time evolution is described by a first-order differential equation, which is the Schrödinger equation for the continuous or analog state vector. As is well-known, linearity of the Schrödinger ansatz implies that any sum of the states with constant coefficients also satisfies the same equation. Hence the flexibility of this class of methods operating with state vectors that permit changes, so that one can switch from one basis to another without altering the sought eigensolutions.
