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The random matrix ensembles are applied to the quantum chaotic systems. The quantum systems are studied using the finite dimensional real, complex and quaternion Hilbert spaces of the eigenfunctions. The linear operators describing the…

Statistical Mechanics · Physics 2007-05-23 Maciej M. Duras

It has been discussed earlier that ( weak quasi-) quantum groups allow for conventional interpretation as internal symmetries in local quantum theory. From general arguments and explicit examples their consistency with (braid-) statistics…

High Energy Physics - Theory · Physics 2009-10-28 Volker Schomerus

We provide a generalization of the idea of unitary designs to cover finite averaging over much more general operations on quantum states. Namely, we construct finite averaging sets for averaging quantum states over arbitrary reductive Lie…

Quantum Physics · Physics 2025-03-24 Marcin Markiewicz , Konrad Schlichtholz

Accurately predicting response properties of molecules such as the dynamic polarizability and hyperpolarizability using quantum mechanics has been a long-standing challenge with widespread applications in material and drug design. Classical…

Chemical Physics · Physics 2020-09-01 Xiaoxia Cai , Wei-Hai Fang , Heng Fan , Zhendong Li

In this paper we generalize the usual model of quantum computer to a model in which the state is an operator of density matrix and the gates are general superoperators (quantum operations), not necessarily unitary. A mixed state (operator…

Quantum Physics · Physics 2007-05-23 Vasily E. Tarasov

Complex numbers appear in the Hilbert space formulation of quantum mechanics, but not in the formulation in phase space. Quantum symmetries are described by complex, unitary or antiunitary operators defining ray representations in Hilbert…

Quantum Physics · Physics 2009-11-11 A. J. Bracken

We describe the implications of permutation symmetry for the state space and dynamics of quantum mechanical systems of matrices of general size $N$. We solve the general 11- parameter permutation invariant quantum matrix harmonic oscillator…

High Energy Physics - Theory · Physics 2022-12-14 George Barnes , Adrian Padellaro , Sanjaye Ramgoolam

We construct quantum evolution operators on the space of states, that realize the metaplectic representation of the modular group SL(2,Z_2^n). This representation acts in a natural way on the coordinates of the non-commutative 2-torus and…

High Energy Physics - Theory · Physics 2007-05-23 E. G. Floratos , S. Nicolis

We study bipartite unitary operators which stay invariant under the local actions of diagonal unitary and orthogonal groups. We investigate structural properties of these operators, arguing that the diagonal symmetry makes them suitable for…

Quantum Physics · Physics 2022-06-08 Satvik Singh , Ion Nechita

Inspired by some problems in Quantum Information Theory, we present some results concerning decompositions of positive operators acting on finite dimensional Hilbert spaces. We focus on decompositions by families having geometrical symmetry…

Functional Analysis · Mathematics 2017-03-23 Maria Anastasia Jivulescu , Ion Nechita , Pasc Gavruta

A non-associative algebra of observables cannot be represented as operators on a Hilbert space, but it may appear in certain physical situations. This article employs algebraic methods in order to derive uncertainty relations and…

High Energy Physics - Theory · Physics 2015-03-31 Martin Bojowald , Suddhasattwa Brahma , Umut Buyukcam , Thomas Strobl

We show that sampling or interpolation formulas in reproducing kernel Hilbert spaces can be obtained by reproducing kernels whose dual systems form molecules, ensuring that the size profile of a function is fully reflected by the size…

Functional Analysis · Mathematics 2022-05-04 José Luis Romero , Jordy Timo van Velthoven , Felix Voigtlaender

This paper is a contribution to the theory of dynamical sampling. Our purpose is twofold. We first consider representations of sequences in a Hilbert space in terms of iterated actions of a bounded linear operator. This generalizes recent…

Functional Analysis · Mathematics 2020-09-11 Ole Christensen , Marzieh Hasannasab , Diana T. Stoeva

It is well known that an (in general, non-commutative) set of non-Hermitian operators $\Lambda_j$ with real eigenvalues need not necessarily represent observables. We describe a specific class of quantum models in which these operators plus…

Quantum Physics · Physics 2022-08-02 Miloslav Znojil

Metrics and pseudometrics are defined on the group of unitary operators in a Hilbert space. Several explicit formulas are derived. A special feature of the work is investigation of pseudometrics in unitary groups. The rich classes of…

Quantum Physics · Physics 2019-09-26 Manas K Patra

Operator learning is reshaping scientific computing by amortizing inference across infinite families of problems. While neural operators (NOs) are increasingly well understood for regression, far less is known for classification and its…

A finite dimensional operator that commutes with some symmetry group admits quotient operators, which are determined by the choice of associated representation. Taking the quotient isolates the part of the spectrum supporting the chosen…

Mathematical Physics · Physics 2023-11-30 Ram Band , Gregory Berkolaiko , Christopher H. Joyner , Wen Liu

We introduce new families of pure quantum states that are constructed on top of the well-known Gilmore-Perelomov group-theoretic coherent states. We do this by constructing unitaries as the exponential of operators quadratic in Cartan…

Quantum Physics · Physics 2021-05-12 Tommaso Guaita , Lucas Hackl , Tao Shi , Eugene Demler , J. Ignacio Cirac

To apply network coding for quantum computation, we study the distributed implementation of unitary operations over all separated input and output nodes of quantum networks. We consider a setting of networks where quantum communication…

Quantum Physics · Physics 2017-11-30 Seiseki Akibue , Mio Murao

Boundedness and compactness properties of multiplication operators on quantum (non-commutative) function spaces are investigated. For endomorphic multiplication operators these properties can be characterized in the setting of quantum…

Operator Algebras · Mathematics 2019-07-25 Pierre de Jager , Louis Labuschagne