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We discuss two different types of issues concerning the quantization of Einstein-Rosen waves. First of all we study in detail the possibility of using the coherent states corresponding to the dynamics of the auxiliary, free Hamiltonian…

General Relativity and Quantum Cosmology · Physics 2008-11-26 J. Fernando Barbero G. , Iñaki Garay , Eduardo J. S. Villaseñor

Operator systems connect operator algebra, free semialgebraic geometry and quantum information theory. In this work we generalize operator systems and many of their theorems. While positive semidefinite matrices form the underlying…

Operator Algebras · Mathematics 2025-12-12 Gemma De les Coves , Mirte van der Eyden , Tim Netzer

In earlier work, we introduced quantum blobs as minimum-uncertainty symplectic ellipsoids in phase space. These objects may be viewed as geometric monads in the Leibnizian sense, representing the elementary units of phase-space structure…

Quantum Physics · Physics 2025-11-11 Maurice de Gosson

We represent a two-qubit density matrix in the basis of Pauli matrix tensor products, with the coefficients constituting a Bloch matrix, analogous to the single qubit Bloch vector. We find the quantum state positivity requirements on the…

Quantum Physics · Physics 2016-11-27 Omar Gamel

In quantum mechanics, predictions are made by way of calculating expectation values of observables, which take the form of Hermitian operators. It is far less common to exploit non-Hermitian operators to perform measurements. Here, we show…

Quantum Physics · Physics 2015-11-04 Eliot Bolduc , Genevieve Gariepy , Jonathan Leach

For one qubit systems, we present a short, elementary argument characterizing unital quantum operators in terms of their action on Bloch vectors. We then show how our approach generalizes to multi-qubit systems, obtaining inequalities that…

Quantum Physics · Physics 2009-11-10 P. S. Bourdon , H. T. Williams

There are six different mathematical formulations of the symmetry group in quantum mechanics, among them the set of pure states $\mathbf{P}$ -- i.e., the set of one-dimensional projections on a complex Hilbert space $H$ -- and the…

Quantum Physics · Physics 2021-11-02 Yaakov Friedman , Antonio M. Peralta

To any action of a compact quantum group on a von Neumann algebra which is a direct sum of factors we associate an equivalence relation corresponding to the partition of a space into orbits of the action. We show that in case all factors…

Operator Algebras · Mathematics 2019-01-29 Kenny De Commer , Paweł Kasprzak , Adam Skalski , Piotr M. Sołtan

We characterize the quasianti-Hermitian quaternionic operators in QQM by means of their spectra; moreover, we state a necessary and sufficient condition for a set of quasianti-Hermitian quaternionic operators to be anti-Hermitian with…

Quantum Physics · Physics 2009-11-10 A. Blasi , G. Scolarici , L. Solombrino

We explore further the suggestion to describe a pre- and post-selected system by a two-state, which is determined by two conditions. Starting with a formal definition of a two-state Hilbert space and basic operations, we systematically…

Quantum Physics · Physics 2009-10-28 B. Reznik , Y. Aharonov

We submit a classical unification of the special and general relativities via the new isominkowskian geometry in which the two relativities are differentiated by the basic unit. We then show that the unification admits an operator image in…

General Physics · Physics 2008-02-03 R. M. Santilli

A simple connection between the universal $R$ matrix of $U_q(sl(2))$ (for spins $\demi$ and $J$) and the required form of the co-product action of the Hilbert space generators of the quantum group symmetry is put forward. This gives an…

High Energy Physics - Theory · Physics 2009-10-28 E. Cremmer , J. -L. Gervais , J. Schnittger

Just as any state of a single qubit or 2-level system can be obtained from any other state by a rotation operator parametrized by three real Euler angles, we show how any state of an n-qubit or 2^n-level system can be obtained from any…

Quantum Physics · Physics 2007-05-23 W. E. Baylis , R. Cabrera , C. Rangan

In this paper such Riemann metrics are established whose Laplace-Beltrami operators are identical to familiar Hamilton operators of elementary particle systems. Such metrics are the natural positive definite invariant metrics defined on…

Spectral Theory · Mathematics 2009-09-23 Zoltan Imre Szabo

Quantum reference frames are needed in quantum theory for much the same reasons that reference frames are in classical theories: to manifest invariance in line with fundamental relativity principles and to provide a basis for the definition…

Quantum Physics · Physics 2025-04-02 Titouan Carette , Jan Głowacki , Leon Loveridge

A Planck-scale minimal observable length appears in many approaches to quantum gravity. It is sometimes argued that this minimal length might conflict with Lorentz invariance, because a boosted observer could see the minimal length further…

General Relativity and Quantum Cosmology · Physics 2009-11-07 Carlo Rovelli , Simone Speziale

The recent developments of the ``connection'' and ``loop'' representations have given the possibility to show that the two representation are equivalent and that it is possible to transform any result from one representation into the other.…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Roberto De Pietri

We show that relativistic rotation transformations represent transfer maps between the laboratory system and a local observer on an observer manifold, rather than an event manifold, in the spirit of C-equivalence. Rotation is, therefore,…

General Mathematics · Mathematics 2024-04-10 Satyanad Kichenassamy

We analyze a class of quantum operations based on a geometrical representation of $d-$level quantum system (or qudit for short). A sufficient and necessary condition of complete positivity, expressed in terms of the quantum Fourier…

Quantum Physics · Physics 2009-11-10 Runyao Duan , Zhengfeng Ji , Yuan Feng , Mingsheng Ying

First, some superluminal phenomena and experiments are introduced briefly. Next, based on the basic principles of the special relativity, the Lorentz transformation (LT) with smaller velocity and the general Lorentz transformation (GLT)…

General Physics · Physics 2010-06-11 Yi-Fang Chang