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The Averaged Null Energy Condition (ANEC) states that the integral along a complete null geodesic of the projection of the stress-energy tensor onto the tangent vector to the geodesic cannot be negative. Exotic spacetimes, such as those…

General Relativity and Quantum Cosmology · Physics 2013-03-14 Eleni-Alexandra Kontou , Ken D. Olum

The averaged null energy condition (ANEC) requires that the integral over a complete null geodesic of the stress-energy tensor projected onto the geodesic tangent vector is never negative. This condition is sufficient to prove many…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Noah Graham , Ken D. Olum

The averaged null energy condition has been recently shown to hold for linear quantum fields in a large class of spacetimes. Nevertheless, it is easy to show by using a simple scaling argument that ANEC as stated cannot hold generically in…

General Relativity and Quantum Cosmology · Physics 2009-12-30 Ulvi Yurtsever

The Averaged Null Energy Condition (ANEC) states that the integral along a complete null geodesic of the projection of the stress-energy tensor onto the tangent vector to the geodesic cannot be negative. ANEC can be used to rule out…

General Relativity and Quantum Cosmology · Physics 2015-07-23 Eleni-Alexandra Kontou

The present article lies at the interface between gravity, a highly nonlinear phenomenon, and quantum field theory. The nonlinear field equations of Einstein permit the theoretical existence of classical wormholes. One of the fundamental…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Kamal K. Nandi , Yuan-Zhong Zhang , Nail G. Migranov

The classic singularity theorems of General Relativity rely on energy conditions that can be violated in semiclassical gravity. Here, we provide motivation for an energy condition obeyed by semiclassical gravity: the smeared null energy…

General Relativity and Quantum Cosmology · Physics 2022-07-20 Ben Freivogel , Eleni-Alexandra Kontou , Dimitrios Krommydas

Considerable interest has recently been expressed regarding the issue of whether or not quantum field theory on a fixed but curved background spacetime satisfies the averaged null energy condition (ANEC). A comment by Wald and Yurtsever…

General Relativity and Quantum Cosmology · Physics 2009-10-22 Matt Visser

Quantum inequalities are constraints on how negative the weighted average of the renormalized stress-energy tensor of a quantum field can be. A null-projected quantum inequality can be used to prove the averaged null energy condition…

General Relativity and Quantum Cosmology · Physics 2015-12-16 Eleni-Alexandra Kontou , Ken D. Olum

The Averaged Null Energy Condition (ANEC) requires that the average along a complete null geodesic of the projection of the stress-energy tensor onto the geodesic tangent vector can never be negative. It is sufficient to rule out many…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Christopher J. Fewster , Ken D. Olum , Michael J. Pfenning

A null line is a complete achronal null geodesic. It is proven that for any quantum fields minimally coupled to semiclassical Einstein gravity, the averaged null energy condition (ANEC) on null lines is a consequence of the generalized…

General Relativity and Quantum Cosmology · Physics 2010-04-06 Aron C. Wall

We describe the different possibilities that a simple and apparently quite harmless classical scalar field theory provides to violate the energy conditions. We demonstrate that a non-minimally coupled scalar field with a positive curvature…

General Relativity and Quantum Cosmology · Physics 2009-10-31 Carlos Barcelo , Matt Visser

We consider averaged null energy conditions (ANEC) for strongly coupled quantum field theories in even (two and four) dimensional curved spacetimes by applying the no-bulk-shortcut principle in the context of the AdS/CFT duality. In the…

High Energy Physics - Theory · Physics 2020-12-02 Norihiro Iizuka , Akihiro Ishibashi , Kengo Maeda

Energy conditions are attempts to summarise the properties of realistic descriptions of matter via constraints on the energy-momentum tensor. This is, for example, useful when one wants to understand the types of spacetime geometry that can…

High Energy Physics - Theory · Physics 2024-11-19 Hidde Stoffels

Quantum fields can notoriously violate the null energy condition (NEC). In a cosmological context, NEC violation can lead to, e.g., dark energy at late times with an equation-of-state parameter smaller than $-1$ and nonsingular bounces at…

General Relativity and Quantum Cosmology · Physics 2025-07-01 Elly Moghtaderi , Brayden R. Hull , Jerome Quintin , Ghazal Geshnizjani

Recently, Larry Ford and Tom Roman have discovered that in a flat cylindrical space, although the stress-energy tensor itself fails to satisfy the averaged null energy condition (ANEC) along the (non-achronal) null geodesics, when the…

General Relativity and Quantum Cosmology · Physics 2009-10-22 Ulvi Yurtsever

The quantum null energy condition (QNEC) is a conjectured bound on components $(T_{kk} = T_{ab} k^a k^b$) of the stress tensor along a null vector $k^a$ at a point $p$ in terms of a second $k$-derivative of the von Neumann entropy $S$ on…

High Energy Physics - Theory · Physics 2017-12-29 Zicao Fu , Jason Koeller , Donald Marolf

Traversable wormhole solutions in General Relativity require exotic matter sources that violate the null energy condition (NEC), and such behavior maybe avoided in modified gravity. In this study, we analyze the energy conditions for…

General Relativity and Quantum Cosmology · Physics 2023-01-25 Anshuman Baruah , Parangam Goswami , Atri Deshamukhya

Wormhole and time machine are very interesting objects in general relativity. However, they need exotic matters which are impossible in classical level to support them. But if we introduce the quantum effects of gravity into the…

General Relativity and Quantum Cosmology · Physics 2010-04-30 Li-Fang Li , Jian-Yang Zhu

We examine the quantum null energy condition (QNEC) for a $2+1$-dimensional conformal field theory (CFT) at strong coupling in the background of a wormhole spacetime by employing the AdS/CFT correspondence. First, we numerically construct a…

High Energy Physics - Theory · Physics 2019-01-14 Akihiro Ishibashi , Kengo Maeda , Eric Mefford

We calculate the stress-energy tensor for a scalar field with general curvature coupling, outside a perfectly reflecting sphere with Dirichlet boundary conditions. For conformal coupling we find that the null energy condition is always…

High Energy Physics - Theory · Physics 2009-11-11 Delia Schwartz-Perlov , Ken D. Olum
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