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We introduce a symmetric operad whose algebras are the Operator Product Expansion (OPE) Algebras of quantum fields. There is a natural classical limit for the algebras over this operad and they are commutative associative algebras with…

High Energy Physics - Theory · Physics 2021-04-13 Nikolay M. Nikolov

Let $\mathbb{P}$ be the complete metric space consisting of positive invertible operators on an infinite-dimensional Hilbert space with the Thompson metric. We introduce the notion of operator means of probability measures on $\mathbb{P}$,…

Functional Analysis · Mathematics 2019-01-15 Fumio Hiai , Yongdo Lim

We argue that topological operators for continuous symmetries written in terms of currents need regularization, which effectively gives them a small but finite width. The regulated operator is a finite tension object which fluctuates. In…

High Energy Physics - Theory · Physics 2025-10-29 Ibrahima Bah , Patrick Jefferson , Konstantinos Roumpedakis , Thomas Waddleton

The spherically symmetric volume operator is discussed and all its eigenstates and eigenvalues are computed. Even though the operator is more complicated than its homogeneous analog, the spectra are related in the sense that the larger…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Martin Bojowald , Rafal Swiderski

To develop a unitary quantum theory with probabilistic description for pseudo- Hermitian systems one needs to consider the theories in a different Hilbert space endowed with a positive definite metric operator. There are different…

Quantum Physics · Physics 2013-05-10 Ananya Ghatak , Bhabani Prasad Mandal

In this paper, we study Hamiltonian operators which are sum of a first order operator and of a Poisson tensor, in two spatial independent variables. In particular, a complete classification of these operators is presented in two and three…

Mathematical Physics · Physics 2025-04-15 Alessandra Rizzo

A complex Hilbert space of dimension six supports at least three but not more than seven mutually unbiased bases. Two computer-aided analytical methods to tighten these bounds are reviewed, based on a discretization of parameter space and…

Quantum Physics · Physics 2011-02-10 Stephen Brierley , Stefan Weigert

The present paper is a sequel to our paper "Metric characterization of isometries and of unital operator spaces and systems". We characterize certain common objects in the theory of operator spaces (unitaries, unital operator spaces,…

Operator Algebras · Mathematics 2012-02-28 David P. Blecher , Matthew Neal

The aim of the present paper is to define compact operators on asymmetric normed spaces and to study some of their properties. The dual of a bounded linear operator is defined and a Schauder type theorem is proved within this framework. The…

Functional Analysis · Mathematics 2007-05-23 Stefan Cobzaş

A set of mutually unbiased bases (MUBs) is said to be unextendible if there does not exist another basis that is unbiased with respect to the given set. Here, we prove the existence of smaller sets of MUBs in prime-squared dimensions…

Quantum Physics · Physics 2015-08-25 Vishakh Hegde , Prabha Mandayam

In a quantum system having a finite number $N$ of orthogonal states, two orthonormal bases $\{a_i\}$ and $\{b_j\}$ are called mutually unbiased if all inner products $<a_i|b_j>$ have the same modulus $1/\sqrt{N}$. This concept appears in…

Quantum Physics · Physics 2007-05-23 Claude archer

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

Relative and center of mass cordinates are used to generalize mutually unbiased bases (MUB) and define mutually unbiased bases (MUCB). Maximal entangled states are given as product staes in the collective varibles

Quantum Physics · Physics 2015-05-14 M. Revzen

The fundamental principles of complementarity and uncertainty are shown to be related to the possibility of joint unsharp measurements of pairs of noncommuting quantum observables. A new joint measurement scheme for complementary…

Quantum Physics · Physics 2009-11-07 P. Busch , C. R. Shilladay

We present a correspondence between positive operator valued measures (POVMs) and sets of generalized coherent states. Positive operator valued measures describe quantum observables and, similarly to quantum states, also quantum observables…

Quantum Physics · Physics 2012-06-06 Teiko Heinosaari , Juha-Pekka Pellonpää

A symmetric function of $N$ variables can be given in terms of symmetric polynomials of these variables. We determine those symmetric polynomials in which the dual differential operators take the neatest form when expressed in terms of our…

Classical Analysis and ODEs · Mathematics 2023-02-02 Shaul Zemel

We describe sets of mutually unbiased bases (MUBs) for quantum states defined over the p-adic numbers Q_p, i.e. the states that can be described as elements of the (rigged) Hilbert space L2(Q_p). We find that for every prime p>2 there are…

Quantum Physics · Physics 2011-09-02 Wim van Dam , Alexander Russell

A quasi-Hermitian operator is an operator that is similar to its adjoint in some sense, via a metric operator, i.e., a strictly positive self-adjoint operator. Whereas those metric operators are in general assumed to be bounded, we analyze…

Mathematical Physics · Physics 2016-10-24 Jean-Pierre Antoine , Camillo Trapani

Maximal sets of mutually unbiased bases are useful throughout quantum physics, both in a foundational context and for applications. To date, it remains unknown if complete sets of mutually unbiased bases exist in Hilbert spaces of…

Quantum Physics · Physics 2026-04-09 Daniel McNulty , Stefan Weigert

The aim of the present paper is, firstly we study the concepts of (m, (q_1, ..., q_d))- partial isometries on a Hilbert space, secondly, we introduce the notion of m- invertibility of tuples of operators as a natural generalization of the…

Functional Analysis · Mathematics 2016-03-01 Ould Ahmed Mahmoud Sid Ahmed