New upper bounds for the $q$-numerical radius of Hilbert space operators

Abstract

This article introduces several new upper bounds for the $q$-numerical radius of bounded linear operators on complex Hilbert spaces. Our results refine some of the existing upper bounds in this field. The $q$-numerical radius inequalities of products and commutators of operators follow as special cases. Finally, some new inequalities for the $q$-numerical radius of $2\times 2$ operator matrices are established.

20 pages