Results 1 to 10 of about 14,182 (265)

On families of twisted power partial isometries

open access: yesKarpatsʹkì Matematičnì Publìkacìï, 2022
We consider families of power partial isometries satisfying twisted commutation relations with deformation parameters $\lambda_{ij}\in\mathbb C$, $|\lambda_{ij}|=1$.
V.L. Ostrovskyi   +2 more
doaj   +1 more source

Detecting mixed-unitary quantum channels is NP-hard [PDF]

open access: yesQuantum, 2020
A quantum channel is said to be a $\textit{mixed-unitary}$ channel if it can be expressed as a convex combination of unitary channels. We prove that, given the Choi representation of a quantum channel $\Phi$, it is NP-hard with respect to polynomial-time
Colin Do-Yan Lee, John Watrous
doaj   +1 more source

Transfer of Unitary Representations [PDF]

open access: yesAsian Journal of Mathematics, 2004
In the present paper, the authors explain and give applications of the notion of transfer between real forms of a semi-simple Lie group \(G^{\mathbb C}\) over \(\mathbb C\), which first appeared in [\textit{N. R. Wallach}, Contemp. Math. 177, 181--216 (1994; Zbl 0833.22021)]. The main idea is that some representation of a real form of \(G^{\mathbb C}\)
Wallach, Nolan R., Zhu, Chen-Bo
openaire   +2 more sources

Representation Matching For Remote Quantum Computing

open access: yesPRX Quantum, 2021
Many quantum computational tasks have inherent symmetries, suggesting a path to enhancing their efficiency and performance. Exploiting this observation, we propose representation matching, a generic probabilistic protocol for reducing the cost of quantum
Yuxiang Yang, Masahito Hayashi
doaj   +1 more source

Algebras Generated by Finite Subgroups of Unitary Groups

open access: yesJournal of Harbin University of Science and Technology, 2021
Group representation theory is one of the most powerful tools to study groups. The unitary group is an important research branch of group theories. We study a class of algebraic structures generated by unitary groups,and we prove that Alg( H) is a von ...
LUO Lai-zhen, LI Xing-hua, TAO Yuan-hong
doaj   +1 more source

On Constructing Informationally Complete Covariant Positive Operator-Valued Measures

open access: yesEntropy, 2023
We study a projective unitary representation of the product G=G˜×G, where G is a locally compact Abelian group and G^ is its dual consisting of characters on G.
Grigori Amosov
doaj   +1 more source

Topological Boundaries of Unitary Representations [PDF]

open access: yesInternational Mathematics Research Notices, 2020
AbstractWe introduce and study a generalization of the notion of the Furstenberg boundary of a discrete group $\Gamma $ to the setting of a general unitary representation $\pi : \Gamma \to B(\mathcal H_\pi )$. This space, which we call the “Furstenberg–Hamana boundary” (or "FH-boundary") of the pair $(\Gamma , \pi )$, is a $\Gamma $-invariant subspace ...
Bearden, Alex, Kalantar, Mehrdad
openaire   +2 more sources

A note on cocycles of unitary representations [PDF]

open access: yesProceedings of the American Mathematical Society, 1976
Given a unitary representation U U of a locally compact abelian group
Parry, W., Schmidt, K.
openaire   +1 more source

Tight Representations of 0-𝐸-Unitary Inverse Semigroups

open access: yesAbstract and Applied Analysis, 2011
We study the tight representation of a semilattice in {0,1} by some examples. Then we introduce the concept of the complex tight representation of an inverse semigroup 𝑆 by the concept of the tight representation of the semilattice of idempotents 𝐸 of 𝑆 ...
Bahman Tabatabaie Shourijeh   +1 more
doaj   +1 more source

The unitary representations of the Poincar\'e group in any spacetime dimension

open access: yesSciPost Physics Lecture Notes, 2021
An extensive group-theoretical treatment of linear relativistic field equations on Minkowski spacetime of arbitrary dimension $D\geqslant 3$ is presented.
Xavier Bekaert, Nicolas Boulanger
doaj   +1 more source

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