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Motivated by a general dilation theory for operator-valued measures, framings and bounded linear maps on operator algebras, we consider the dilation theory of the above objects with special structures. We show that every operator-valued…

Functional Analysis · Mathematics 2014-11-18 Deguang Han , David R. Larson , Bei Liu , Rui Liu

We give new necessary and sufficient conditions for the numerical range $W(T)$ of an operator $T \in \mathcal{B}(\mathcal{H})$ to be a subset of the closed elliptical set $K_\delta \subseteq \mathbb{C}$ given by \[ K_\delta {\stackrel{\rm…

Functional Analysis · Mathematics 2024-06-10 Jim Agler , Zinaida A. Lykova , N. J. Young

Density operators are one of the key ingredients of quantum theory. They can be constructed in two ways: via a convex sum of `doubled kets' (i.e. mixing), and by tracing out part of a `doubled' two-system ket (i.e. dilation). Both…

Quantum Physics · Physics 2017-04-10 Maaike Zwart , Bob Coecke

A new functional calculus, developed recently for a fully non-perturbative treatment of quantum gravity, is used to begin a systematic construction of a quantum theory of geometry. Regulated operators corresponding to areas of 2-surfaces…

General Relativity and Quantum Cosmology · Physics 2010-04-06 Abhay Ashtekar , Jerzy Lewandowski

We propose the construction of equations of motion based on symmetries in quantum-mechanical systems, using Heisenberg's uncertainty principle as a minimal foundation. From canonical operators, two spaces of conjugate operators are…

Quantum Physics · Physics 2025-08-15 Enrique Casanova , José Rojas , Melvin Arias

Quantum operations (QO) describe any state change allowed in quantum mechanics, such as the evolution of an open system or the state change due to a measurement. We address the problem of which unitary transformations and which observables…

Quantum Physics · Physics 2009-11-10 F. Buscemi , G. M. D'Ariano , M. F. Sacchi

The complex Hilbert space of standard quantum mechanics may be treated as a real Hilbert space. The pure states of the complex theory become mixed states in the real formulation. It is then possible to generalize standard quantum mechanics,…

Quantum Physics · Physics 2007-05-23 Jan Myrheim

We consider continuous structures which are obtained from finite dimensional Hilbert spaces over $\mathbb{C}$ by adding some unitary operators. Quantum automata and circuits are naturally interpretable in such structures. We consider…

Logic · Mathematics 2019-01-16 A. Ivanov

The universal enveloping algebra U(g) of a Lie algebra g acts on its representation ring R through D(R), the ring of differential operators on R. A quantised universal enveloping algebra (or "quantum group") is a deformation of a universal…

Quantum Algebra · Mathematics 2007-05-23 Uma N. Iyer , Timothy C. McCune

Given a row contraction of operators on Hilbert space and a family of projections on the space which stabilize the operators, we show there is a unique minimal joint dilation to a row contraction of partial isometries which satisfy natural…

Functional Analysis · Mathematics 2007-05-23 Michael T. Jury , David W. Kribs

We show that any bounded analytic semigroup on $L^p$ (with $1<p<\infty$) whose negative generator admits a bounded $H^{\infty}$ functional calculus with respect to some angle $< \pi/2$ can be dilated into a bounded analytic semigroup…

Functional Analysis · Mathematics 2015-12-17 Cédric Arhancet , Stephan Fackler , Christian Le Merdy

Density operators are one of the key ingredients of quantum theory. They can be constructed in two ways: via a convex sum of 'doubled kets' (i.e. mixing), and by tracing out part of a 'doubled' two-system ket (i.e. dilation). Both…

Quantum Physics · Physics 2018-03-05 Maaike Zwart , Bob Coecke

We investigate some particular completely positive maps which admit a stable commutative Von Neumann subalgebra. The restriction of such maps to the stable algebra is then a Markov operator. In the first part of this article, we propose a…

Mathematical Physics · Physics 2015-09-17 Ivan Bardet

Generalized virial theorem for quantum mechanical nonrelativistic and relativistic systems with translational and rotational symmetry is derived in the form of the commutator between the generator of dilations G and the Hamiltonian H. If…

Quantum Physics · Physics 2013-02-27 Domagoj Kuic

We investigate a one dimensional quantum mechanical model, which is invariant under translations and dilations but does not respect the conventional conformal invariance. We describe the possibility of modifying the conventional conformal…

High Energy Physics - Theory · Physics 2011-06-27 Shih-Hao Ho

This paper studies random operator-valued positive definite (p.d.) kernels and their connection to moment dilations. A class of random p.d. kernels is introduced in which the positivity requirement is imposed only in expectation, extending…

Functional Analysis · Mathematics 2025-08-15 James Tian

We consider characterisations of unitary dilations and approximations of irreversible classical dynamical systems on a Hilbert space. In the commutative case, building on the work in [9], one can express well known approximants (e.g. Hille-…

Functional Analysis · Mathematics 2023-07-24 Raj Dahya

There are several proofs of the classical commutant lifting and intertwining lifting theorems in the literature. In this article, we present analogous proofs to a few $Q$-commuting lifting and $Q$-intertwining lifting theorems. We provide…

Functional Analysis · Mathematics 2022-10-25 Sourav Pal , Prajakta Sahasrabuddhe

The isomorphism between the reduction algebra and the invariant differential operators on G/H is sketched.

Quantum Algebra · Mathematics 2011-03-24 Panagiotis Batakidis

A new analytic model for left-invertible operators, which extends both Shimorin's analytic model for left-invertible and analytic operators and Gellar's model for bilateral weighted shift is introduced and investigated. We show that a…

Functional Analysis · Mathematics 2025-05-13 Pawel Pietrzycki