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Uncertainty relations are often considered to be a measure of incompatibility of noncommuting observables. However, such a consideration is not valid in general, motivating the need for an alternate measure that applies to any set of…

Quantum Physics · Physics 2015-06-12 Somshubhro Bandyopadhyay , Prabha Mandayam

In this note, some inequalities involving operator means of sectorial matrices are proved which are generalizations and refinements of previous known results. Among them, let $A$ and $B$ be two accretive matrices with…

Functional Analysis · Mathematics 2023-05-09 M. Khosravi , A. Sheikhhosseini , S. Malekinejad

We consider in this paper two different types of the weighted geometric means of positive definite operators. We show the component-wise bijection of these geometric means and give a geometric property of the spectral geometric mean as a…

Functional Analysis · Mathematics 2020-09-23 Sejong Kim

Accretive and monotone operator theory are central branches of nonlinear functional analysis and constitute the abstract study of set-valued mappings between function spaces. This paper deals with the computational properties of certain…

Logic · Mathematics 2022-05-10 Nicholas Pischke

In a parametrized and constrained Hamiltonian system, an observable is an operator which commutes with all (first-class) constraints, including the super-Hamiltonian. The problem of the frozen formalism is to explain how dynamics is…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Arlen Anderson

On finite dimensional spaces, it is apparent that an operator is the product of two positive operators if and only if it is similar to a positive operator. Here, the class ${\mathcal L}^{+2}$ of bounded operators on separable infinite…

Functional Analysis · Mathematics 2021-01-27 Maximiliano Contino , Michael A. Dritschel , Alejandra Maestripieri , Stefania Marcantognini

We introduce certain linear positive operators and study some approximation properties of these operators in the space of functions, continuous on a compact set, of two variables. We also find the order of this approximation by using…

Classical Analysis and ODEs · Mathematics 2007-09-24 Fatma Tasdelen , Ali Olgun , Gulen Bascanbaz-Tunca

Loewner partial order plays a very important role in metric topology and operator inequality on the open convex cone of positive invertible operators. In this paper we consider a family G of the ordered means for positive invertible…

Functional Analysis · Mathematics 2020-09-23 Sejong Kim

In this article we present some new comparisons between the Heinz and Heron operator means, which improve some recent results known from the literature. We derive some refinements of these inequalities for unitarily invariant norms with the…

Functional Analysis · Mathematics 2021-05-11 A. G. Ghazanfari

We introduce and study the notion of orthogonality for two operators in the context of weighted backward shifts on $\ell_p(\mathbb{Z}_+)$, $1\leq p<\infty$. Two continuous linear operators $T_1$ and $T_2$ acting on a Polish topological…

Functional Analysis · Mathematics 2023-12-22 Sophie Grivaux , Etienne Matheron , Quentin Menet

It is shown that a positive (bounded linear) operator on a Hilbert space with trivial kernel is unitarily equivalent to a Hankel operator that satisfies double positivity condition if and only if it is non-invertible and has simple spectrum…

Functional Analysis · Mathematics 2020-09-07 Piotr Niemiec

In this paper we consider power means of positive Hilbert space operators both in the conventional and in the Kubo-Ando senses. We describe the corresponding isomorphisms (bijective transformations respecting those means as binary…

Functional Analysis · Mathematics 2019-09-26 Lajos Molnár

In this work, an operator superquadratic function (in operator sense) for positive Hilbert space operators is defined. Several examples with some important properties together with some observations which are related to the operator…

Functional Analysis · Mathematics 2019-12-17 M. W. Alomari

This paper concerns three classes of real-valued functions on intervals, operator monotone functions, operator convex functions, and strongly operator convex functions. Strongly operator convex functions were previously treated in [3] and…

Functional Analysis · Mathematics 2018-05-29 Lawrence G. Brown , Mitsuru Uchiyama

We look at Toeplitz operators $T_\nu$ on the Fock Space (also known as the Segal-Bargmann space) which have a positive Borel measure $\nu$ as a symbol. We characterize when $\left(T_\nu\right)^s$ for $0<s\leq 1$ is in the symmetrically…

Functional Analysis · Mathematics 2018-06-29 Adam Orenstein

We extend Hardy's inequality from sequences of non-negative numbers to sequences of positive semi-definite operators if the parameter p satisfies 1<p<=2, and to operators under a trace for arbitrary p>1. Applications to trace functions are…

Operator Algebras · Mathematics 2010-01-13 Frank Hansen

We characterize strong type and weak type inequalities with two weights for positive operators on filtered measure spaces. These estimates are probabilistic analogues of two-weight inequalities for positive operators associated to the…

Probability · Mathematics 2019-04-03 Wei Chen , Chunxiang Zhu , Yahui Zuo , Yong Jiao

We will consider about some inequalities on operator means for more than three operators, for instance, ALM and BMP geometric means will be considered. Moreover, log-Euclidean and logarithmic means for several operators will be treated.

Functional Analysis · Mathematics 2019-12-19 Shuhei Wada , Takeaki Yamazaki

In this paper we initiate the study of real operator monotonicity for functions of tuples of operators, which are multivariate structured maps with a functional calculus called free functions that preserve the order between real parts (or…

Functional Analysis · Mathematics 2019-12-19 Marcell Gaál , Miklós Pálfia

In the context of general Banach spaces characterizations for the maximal monotonicity of operators with non-empty domain interior as well as stronger continuity properties for such operators are provided.

Functional Analysis · Mathematics 2011-02-25 M. D. Voisei