We exhibit a way to associate a quantum walk (QW) on the non-negative
integers to any probability measure on the unit circle. This forces us to
consider one step transitions that are not traditionally allowed. We illustrate
this in the case of a very interesting measure, originally proposed by F. Riesz
for a different purpose.
This paper is devoted to the study of general (Laurent) polynomial
modifications of moment functionals on the unit circle, i.e., associated with
hermitian Toeplitz matrices. We present a new approach which allows us to study
polynomial modifications of arbitrary degree.