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Related papers: Achronal averaged null energy condition

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Recently, a de-Sitter epoch has been found in the new model of loop quantum cosmology which is governed by the scalar constraint with both of Euclidean and Lorentz terms. The singularity free bounce in the new LQC model and the emergent…

General Relativity and Quantum Cosmology · Physics 2021-08-30 Gaoping Long , Yunlong Liu , Xiangdong Zhang

We give a conjecture on the lower bound of the ADM mass $M$ by using the null energy condition. The conjecture includes a Penrose-like inequality $3M\geq\kappa\mathcal{A}/(4\pi)+\sqrt{\mathcal{A}/4\pi}$ and the Penrose inequality $…

General Relativity and Quantum Cosmology · Physics 2022-09-02 Run-Qiu Yang , Li Li , Rong-Gen Cai

In the context of Einstein gravity, if the null energy condition (NEC) is satisfied, the energy density in expanding space-times always decreases while in contracting space-times the energy density grows and the universe eventually…

General Relativity and Quantum Cosmology · Physics 2016-07-04 Anna Ijjas , Justin Ripley , Paul J. Steinhardt

We calculate renormalised vacuum expectation values of electromagnetic stress-energy tensor in the static spherically-symmetrical wormhole topology. We find that for metric tensor sufficiently slow varied with distance violation of the…

General Relativity and Quantum Cosmology · Physics 2010-11-19 V. Khatsymovsky

The null energy condition (NEC) is a cornerstone of general relativity, and its violation could leave observable imprints in the cosmic gravitational wave spectrum. Theoretical models suggest that NEC violations during inflation can amplify…

General Relativity and Quantum Cosmology · Physics 2025-03-28 Zu-Cheng Chen , Lang Liu

A fundamental property of Morris-Thorne wormholes is the so-called flare-out condition that automatically results in a violation of the null energy condition (NEC) in classical general relativity. By contrast, in $f(R)$ modified gravity,…

General Relativity and Quantum Cosmology · Physics 2020-08-20 Peter K. F. Kuhfittig

It has been suggested that the cosmological constant is a variable dynamical quantity. A class of solution has been presented for the spherically symmetric space time describing wormholes by assuming the erstwhile cosmological constant…

General Relativity and Quantum Cosmology · Physics 2008-11-26 F. Rahaman , M. Kalam , M. Sarker , A. Ghosh , B. Raychaudhuri

We study the Null Energy Condition (NEC) arising from the Virasoro constraint on the string worldsheet. We then analyze how the NEC in the external spacetime directions emerges under general time-dependent string compactifications. Finally,…

High Energy Physics - Theory · Physics 2026-03-13 Mir Mehedi Faruk

We use holography to prove the Quantum Null Energy Condition (QNEC) at leading order in large-$N$ for CFTs and relevant deformations of CFTs in Minkowski space which have Einstein gravity duals. Given any codimension-2 surface $\Sigma$…

High Energy Physics - Theory · Physics 2016-07-20 Jason Koeller , Stefan Leichenauer

We establish the relationship between the space-time structure of regular spherically-symmetrical black holes and the character of violation of the strong energy condition (SEC). It is shown that it is violated in any static region under…

General Relativity and Quantum Cosmology · Physics 2014-11-20 O. B. Zaslavskii

Although wormholes can be treated as topological objects in spacetime and from a global point-of-view, a precise definition of what a wormhole throat is and where it can be located can be developed and treated entirely in terms of local…

General Relativity and Quantum Cosmology · Physics 2007-05-23 David Hochberg , Matt Visser

For an arbitrary Tolman wormhole, unconstrained by symmetry, we shall define the bounce in terms of a three-dimensional edgeless achronal spacelike hypersurface of minimal volume. (Zero trace for the extrinsic curvature plus a "flare-out"…

General Relativity and Quantum Cosmology · Physics 2009-10-31 David Hochberg , Carmen Molina-Paris , Matt Visser

We prove a lower bound on the integrated null energy along achronal geodesic segments using induced gravity on a brane in AdS/CFT. The bound follows from the assumption that bulk causality respects brane causality, and matches a bound…

High Energy Physics - Theory · Physics 2019-02-20 Stefan Leichenauer , Adam Levine

We study violations of the Null Energy Condition (NEC) in Quantum Field Theory (QFT) and their implications. For the first part of the project, we examine these violations for classes of already known and novel (first discussed here) QFT…

High Energy Physics - Theory · Physics 2018-06-04 Dimitrios Krommydas

We use the formulation of asymptotically anti-de Sitter boundary conditions given by Ashtekar and Magnon to obtain a coordinate expression for the general asymptotically AdeS metric in a neighbourhood of infinity. From this, we are able to…

General Relativity and Quantum Cosmology · Physics 2010-04-06 E. Woolgar

The usual scenario of ``eternal inflation'' involves an approximately de Sitter spacetime undergoing upward fluctuations of the local expansion rate $H$. This spacetime requires frequent violations of the Null Energy Condition (NEC). We…

General Relativity and Quantum Cosmology · Physics 2020-07-27 Serge Winitzki

Building on a series of earlier papers [gr-qc/9604007, gr-qc/9604008, gr-qc/9604009], I investigate the various point-wise and averaged energy conditions in the Unruh vacuum. I consider the quantum stress-energy tensor corresponding to a…

General Relativity and Quantum Cosmology · Physics 2009-10-30 Matt Visser

We prove a conjectured lower bound on $\left< T_{--}(x) \right>_\psi$ in any state $\psi$ of a relativistic QFT dubbed the Quantum Null Energy Condition (QNEC). The bound is given by the second order shape deformation, in the null…

High Energy Physics - Theory · Physics 2020-03-04 Srivatsan Balakrishnan , Thomas Faulkner , Zuhair U. Khandker , Huajia Wang

Traversable wormholes in General Relativity (GR) require exotic matter sources that violate the null energy condition (NEC), and such behavior may be avoided in modified gravity. Moreover, the concept of non-commutative geometry as a…

General Relativity and Quantum Cosmology · Physics 2022-10-18 Anshuman Baruah , Parangam Goswami , Atri Deshamukhya

Inflation and dark energy (DE), both featuring accelerated expansion, are crucial components of modern cosmology. As indicated by singularity theorems, null energy condition (NEC) violation is essential for resolving the initial singularity…

General Relativity and Quantum Cosmology · Physics 2025-12-08 Gen Ye , Yong Cai
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