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From the noncommutative nature of quantum mechanics, estimation of canonical observables $\hat{q}$ and $\hat{p}$ is essentially restricted in its performance by the Heisenberg uncertainty relation, $\mean{\Delta \hat{q}^2}\mean{\Delta…

Quantum Physics · Physics 2007-09-24 Naoki Yamamoto , Shinji Hara

Minimal and maximal uncertainties of position measurements are widely considered possible hallmarks of low-energy quantum as well as classical gravity. While General Relativity describes interactions in terms of spatial curvature, its…

General Relativity and Quantum Cosmology · Physics 2023-03-23 Fabian Wagner

The $f(R)$ gravity models formulated in Einstein conformal frame are equivalent to Einstein gravity together with a minimally coupled scalar field. The scalar field couples with the matter sector and the coupling term is given by the…

General Relativity and Quantum Cosmology · Physics 2012-07-24 Yousef Bisabr

The Robertson's formulation of the uncertainty relation is the most widely accepted form of the Heisenberg uncertainty relation (HUR). It gets modified when we consider it for entangled particles. But this formulation does not consider the…

Quantum Physics · Physics 2017-06-29 Harris Varghese , M. Ravendranadhan

We consider a possibility to construct a quantum-mechanical model of spacetime, where Planck size quantum black holes act as the fundamental constituents of space and time. Spacetime is assumed to be a graph, where black holes lie on the…

General Relativity and Quantum Cosmology · Physics 2007-06-20 Jarmo Makela

Despite its enormous empirical success, the formalism of quantum theory still raises fundamental questions: why is nature described in terms of complex Hilbert spaces, and what modifications of it could we reasonably expect to find in some…

Quantum Physics · Physics 2017-04-27 Marius Krumm , Howard Barnum , Jonathan Barrett , Markus P. Mueller

We propose that in time dependent backgrounds the holographic principle should be replaced by the generalized second law of thermodynamics. For isotropic open and flat universes with a fixed equation of state, the generalized second law…

High Energy Physics - Theory · Physics 2009-10-31 Richard Easther , David A. Lowe

Holographic entanglement entropy is a key concept linking quantum information theory and gravity. Since the original conjecture of Ryu and Takayanagi, holographic entanglement entropy has been generalized beyond Einstein--Hilbert gravity to…

High Energy Physics - Theory · Physics 2026-02-13 Dušan Đorđević , Dragoljub Gočanin

Now that the Bekenstein-Hawking entropy has been found within the traditional theory, its physical interpretation should hide in quantum field theory in curved spacetime (only its quantum corrections require a detailed knowledge of quantum…

General Relativity and Quantum Cosmology · Physics 2012-05-30 Zhi-Yong Wang

A universal formulation of uncertainty relations for quantum measurements is presented with additional focus on the representability of quantum observables by classical observables over a given state. Owing to the simplicity and operational…

Quantum Physics · Physics 2022-04-01 Jaeha Lee

We propose a novel framework for the quantum geometry of expectation values over arbitrary sets of operators and establish a link between this geometry and the eigenstates of Hamiltonian families generated by these operators. We show that…

Quantum Physics · Physics 2023-06-21 Chaoming Song

This paper explores stability of the Einstein universe against linear homogeneous perturbations in the background of $f(\mathcal{G},T)$ gravity. We construct static as well as perturbed field equations and investigate stability regions for…

General Relativity and Quantum Cosmology · Physics 2017-07-26 M. Sharif , Ayesha Ikram

Thermodynamic uncertainty relations (TURs) and kinetic uncertainty relations (KURs) provide tradeoff relations between measurement precision and thermodynamic cost such as entropy production and activity. Conventionally, these relations are…

Statistical Mechanics · Physics 2024-12-16 Euijoon Kwon , Jae Sung Lee

In this article we examine a Generalized Uncertainty Principle which differs from the Heisenberg Uncertainty Principle by terms linear and quadratic in particle momenta, as proposed by the authors in an earlier paper. We show that this…

High Energy Physics - Theory · Physics 2013-05-21 Ahmed Farag Ali , Saurya Das , Elias C. Vagenas

A general theory of preparational uncertainty relations for a quantum particle in one spatial dimension is developed. We derive conditions which determine whether a given smooth function of the particle's variances and its covariance is…

Quantum Physics · Physics 2016-10-18 Spiros Kechrimparis , Stefan Weigert

The paper deals with universal thermodynamics for FRW model of the universe bounded by apparent (or event) horizon. Assuming Hawking temperature on the horizon, the unified first law is examined on the horizon for different gravity…

General Relativity and Quantum Cosmology · Physics 2016-05-17 Saugata Mitra , Subhajit Saha , Subenoy Chakraborty

The ER=EPR conjecture states that quantum entanglement between boundary degrees of freedom leads to the emergence of bulk spacetime itself. Although this has been tested extensively in String Theory for asymptotically anti-de Sitter…

High Energy Physics - Theory · Physics 2025-05-21 Suddhasattwa Brahma , Lucas Hackl , Moatsem Hassan , Xiancong Luo

An approach to quantum gravity and cosmology is proposed based on a synthesis of four elements: 1) the Bekenstein bound and the related holographic hypothesis of 't Hooft and Susskind, 2) topological quantum field theory, 3) a new approach…

General Relativity and Quantum Cosmology · Physics 2008-02-03 Lee Smolin

An one-parameter regularization freedom of the Hamiltonian constraint for loop quantum gravity is analyzed. The corresponding spatially flat, homogenous and isotropic model includes the two well-known models of loop quantum cosmology as…

General Relativity and Quantum Cosmology · Physics 2021-11-12 Xiangdong Zhang , Gaoping Long , Yongge Ma

We show that ${\cal N}=1$ supergravity with a cosmological constant can be expressed as constrained topological field theory based on the supergroup $Osp(1|4)$. The theory is then extended to include timelike boundaries with finite spatial…

High Energy Physics - Theory · Physics 2009-10-31 Yi Ling , Lee Smolin
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