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Generalized uncertainty principles are able to serve as useful descriptions of some of the phenomenology of quantum gravity effects, providing an intuitive grasp on non-trivial space-time structures such as a fundamental discreteness of…

High Energy Physics - Theory · Physics 2015-06-03 Martin Bojowald , Achim Kempf

This essay argues that when measurement processes involve energies of the order of the Planck scale, the fundamental assumption of locality may no longer be a good approximation. Idealized position measurements of two distinguishable…

General Relativity and Quantum Cosmology · Physics 2008-11-26 D. V. Ahluwalia

In previous work we discussed the quantization of paths in spacetime. Building on these ideas we have developed a mathematically coherent theory addressing a number of open questions concerning Loop Quantum Gravity. Our approach develops a…

General Relativity and Quantum Cosmology · Physics 2019-02-07 James Moffat , Charles H. -T. Wang

The conventional view, that Einstein was wrong to believe that quantum physics is local and deterministic, is challenged. A parametrised model, Q, for the state vector evolution of spin 1/2 particles during measurement is developed. Q draws…

Quantum Physics · Physics 2008-02-03 T. N. Palmer

In this paper a new formulation of quantum dynamics of totally constrained systems is developed, in which physical quantities representing time are included as observables. In this formulation the hamiltonian constraints are imposed on a…

General Relativity and Quantum Cosmology · Physics 2010-11-19 Hideo Kodama

We propose a new measure of relative incompatibility for a quantum system with respect to two non-commuting observables, and call it quantumness of relative incompatibility. In case of a classical state, order of observation is…

Quantum Physics · Physics 2019-09-30 Manish Kumar Shukla , Rounak Mundra , Arun K Pati , Indranil Chakrabarty , Junde Wu

We develop a general, non-probabilistic model of prediction which is suitable for assessing the (un)predictability of individual physical events. We use this model to provide, for the first time, a rigorous proof of the unpredictability of…

Quantum Physics · Physics 2015-10-06 Alastair A. Abbott , Cristian S. Calude , Karl Svozil

Local observables in (perturbative) quantum gravity are notoriously hard to define, since the gauge symmetry of gravity -- diffeomorphisms -- moves points on the manifold. In particular, this is a problem for backgrounds of high symmetry…

General Relativity and Quantum Cosmology · Physics 2023-11-14 Markus B. Fröb , Albert Much , Kyriakos Papadopoulos

We study how meaningful physical predictions can arise in nonperturbative quantum gravity in a closed Lorentzian universe. In such settings, recent developments suggest that the quantum gravitational Hilbert space is one-dimensional and…

High Energy Physics - Theory · Physics 2025-06-17 Yasunori Nomura , Tomonori Ugajin

The origin of non-classical correlations is difficult to identify since the uncertainty principle requires that information obtained about one observable invariably results in the disturbance of any other non-commuting observable. Here,…

Quantum Physics · Physics 2014-07-01 Holger F. Hofmann

A possible model for quantum kinematics of a test particle in a curved space-time is proposed. Every reasonable neighbourhood V_e of a curved space-time can be equipped with a nonassociative binary operation called the geodesic…

High Energy Physics - Theory · Physics 2011-04-15 P. Kuusk , J. Ord

We define quantum observables associated with Einstein localisation in space-time. These observables are built on Poincare' and dilatation generators. Their commutators are given by spin observables defined from the same symmetry…

Quantum Physics · Physics 2009-10-31 Marc-Thierry Jaekel , Serge Reynaud

In the literature on quantum reference frames, the internal (relative) properties of a system are defined as those which are preserved under an arbitrary change of reference frame. For a system of quantum spins, these are all properties…

Quantum Physics · Physics 2016-10-10 Jacques Pienaar

Macroscopic observables in a quantum spin system are given by sequences of spatial means of local elements $\frac{1}{2n+1}\sum_{j=-n}^n\gamma_j(A_{i}), \; n\in{\mathbb N},\; i=1,...,m$ in a UHF algebra. One of their properties is that they…

Operator Algebras · Mathematics 2013-04-03 Yoshiko Ogata

The notion of "closed systems" in Quantum Mechanics is discussed. For this purpose, we study two models of a quantum-mechanical system $P$ spatially far separated from the "rest of the universe" $Q$. Under reasonable assumptions on the…

Mathematical Physics · Physics 2015-05-06 Jérémy Faupin , Jürg Fröhlich , Baptiste Schubnel

The need for a time-shift invariant formulation of quantum theory arises from fundamental symmetry principles as well as heuristic cosmological considerations. Such a description then leaves open the question of how to reconcile global…

Quantum Physics · Physics 2019-06-26 Leon Loveridge , Takayuki Miyadera

Maximum likelihood estimation is applied to the determination of an unknown quantum measurement. The measuring apparatus performs measurements on many different quantum states and the positive operator-valued measures governing the…

Quantum Physics · Physics 2009-11-07 Jaromir Fiurasek

This paper is a continuation of the paper [V.S.Mashkevich, gr-qc/9409010]. Indeterministic quantum gravity is a theory that unifies general relativity and quantum theory involving indeterministic conception, i.e., quantum jumps. By the same…

General Relativity and Quantum Cosmology · Physics 2016-08-31 Vladimir S. Mashkevich

The generalized uncertainty connection between the fluctuations of a quantum observable and its temporal derivative is derived in this study, we demonstrate that the product of an observable's uncertainties and its time derivative is…

Quantum Physics · Physics 2025-08-26 Tarek Yehia

A gauge invariant mathematical formalism based on deformation quantization is outlined to model an $\mathcal{N}=2$ supersymmetric system of a spin $1/2$ charged particle placed in a nocommutative plane under the influence of a vertical…

Mathematical Physics · Physics 2024-07-02 Md. Rafsanjany Jim , S. Hasibul Hassan Chowdhury