Abstract:
In $L_2(\mathbb{R}^d)$, we
consider a self-adjoint operator
which is the sum of a convolution operator and a potential.
With minimal assumptions on the convolution kernel and the potential,
we describe
the location of its essential spectrum
and
give
sufficient conditions for the existence of
infinite series of discrete eigenvalues
accumulating at the edges of the essential spectrum.
We also discuss the case
where
a non-empty discrete spectrum appears in gaps of the essential spectrum.
Keywords:convolution operators with potentials, infinite series of eigenvalues,
gaps in the essential spectrum, eigenvalues in gaps.