The essential norm of the generalized Hankel operators on the Bergman space of the unit ball in .
We compute the essential Taylor spectrum of a tuple of analytic Toeplitz operators on , where D is a strictly pseudoconvex domain. We also provide specific formulas for the index of provided that is a compact subset of D.
Let be a positive Borel measure on the complex plane and let with . We study the generalized Toeplitz operators on the Fock space . We prove that is bounded (or compact) on if and only if is a Fock-Carleson measure (or vanishing Fock-Carleson measure). Furthermore, we give a necessary and sufficient condition for to be in the Schatten -class for .
In this talk we explain a simple treatment of the quantum Birkhoff normal form for semiclassical pseudo-differential operators with smooth coefficients. The normal form is applied to describe the discrete spectrum in a generalised non-degenerate potential well, yielding uniform estimates in the energy . This permits a detailed study of the spectrum in various asymptotic regions of the parameters , and gives improvements and new proofs for many of the results in the field. In the completely resonant...
We consider the solution operator to the -operator restricted to forms with coefficients in . Here denotes -forms with coefficients in , is the corresponding -space and is a suitable rotation-invariant absolutely continuous finite measure. We will develop a general solution formula to . This solution operator will have the property . As an application of the solution formula we will be able to characterize compactness of the solution operator in terms of compactness of commutators...