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Related papers: Semi-local Bounds on Null Energy in QFT

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The null energy condition (NEC), an important assumption of the Penrose singularity theorem, is violated by quantum fields. The natural generalization of the NEC in quantum field theory, the renormalized null energy averaged over a finite…

High Energy Physics - Theory · Physics 2021-11-11 Jackson R. Fliss , Ben Freivogel , Eleni-Alexandra Kontou

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

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

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

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

The Quantum Null Energy Condition (QNEC) is a new local energy condition that a general Quantum Field Theory (QFT) is believed to satisfy, relating the classical null energy condition (NEC) to the second functional derivative of the…

High Energy Physics - Theory · Physics 2018-07-04 Christian Ecker , Daniel Grumiller , Wilke van der Schee , Philipp Stanzer

We investigate the quantum null energy condition (QNEC) in holographic CFTs, focusing on half-spaces and particular classes of states. We present direct, and in certain cases nonperturbative, calculations for both the diagonal and off-…

High Energy Physics - Theory · Physics 2018-09-26 Zuhair U. Khandker , Sandipan Kundu , Daliang Li

We prove the Quantum Null Energy Condition (QNEC), a lower bound on the stress tensor in terms of the second variation in a null direction of the entropy of a region. The QNEC arose previously as a consequence of the Quantum Focussing…

High Energy Physics - Theory · Physics 2016-01-20 Raphael Bousso , Zachary Fisher , Jason Koeller , Stefan Leichenauer , Aron C. Wall

The quantum null energy condition (QNEC) is a quantum generalization of the null energy condition which gives a lower bound on the null energy in terms of the second derivative of the von Neumann entropy or entanglement entropy of some…

High Energy Physics - Theory · Physics 2020-03-30 Taha A Malik , Rafael Lopez-Mobilia

The quantum null energy condition (QNEC) is a lower bound on the expectation value of the null-null component of the energy-momentum tensor in terms of null variations of the entanglement entropy. A stronger version of the QNEC (the primary…

High Energy Physics - Theory · Physics 2025-06-17 Tanay Kibe , Pratik Roy

The Quantum Null Energy Condition (QNEC) relates energy to the second variation of entropy in relativistic quantum field theory. We use the QNEC inequality to bound entanglement entropy in quenches. At early times the entanglement entropy…

High Energy Physics - Theory · Physics 2019-09-04 Márk Mezei , Julio Virrueta

The Quantum Null Energy Condition (QNEC) is a lower bound on the stress-energy tensor in quantum field theory that has been proved quite generally. It can equivalently be phrased as a positivity condition on the second null shape derivative…

High Energy Physics - Theory · Physics 2021-02-03 Mudassir Moosa , Pratik Rath , Vincent Paul Su

We derive new families of quantum null energy inequalities (QNEIs), i.e. bounds on integrated null energy, in quantum field theories in two and higher dimensions. These are universal, state-independent lower bounds on semi-local integrals…

High Energy Physics - Theory · Physics 2026-04-17 Jackson R. Fliss , Andrew Rolph

Energy conditions are crucial for understanding why exotic phenomena such as traversable wormholes and closed timelike curves remain elusive. In this paper, we prove the Double Smeared Null Energy Condition (DSNEC) for the fermionic free…

General Relativity and Quantum Cosmology · Physics 2025-07-03 Duarte Fragoso , Lihan Guo

We consider the Quantum Null Energy Condition (QNEC) for holographic conformal field theories in two spacetime dimensions (CFT$_2$). We show that QNEC saturates for all states dual to vacuum solutions of AdS$_3$ Einstein gravity, including…

High Energy Physics - Theory · Physics 2019-04-04 Christian Ecker , Daniel Grumiller , Wilke van der Schee , Shahin Sheikh-Jabbari , Philipp Stanzer

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

The violation of the null energy condition (NEC) is essential for constructing nonsingular cosmological scenarios, such as Genesis cosmology, which avoids the initial singularity by initiating cosmic evolution from an asymptotically…

General Relativity and Quantum Cosmology · Physics 2026-03-19 Dong-Hui Yu , Mian Zhu , Yong Cai

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 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

Quantum null energy condition (QNEC) is usually stated as a bound on the expectation value of null components of the stress energy tensor at a point in terms of second null shape variations of the entanglement entropy at the same point. It…

High Energy Physics - Theory · Physics 2023-10-17 Pratik Roy
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