How Much NEC Breaking Can the Universe Endure?

Abstract

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 early times. However, it is expected that there should still be a limit in semiclasssical gravity to how much `negative energy' can accumulate over time and in space as a result of quantum effects. In the course of formulating quantum-motivated energy conditions, the smeared null energy condition has emerged as a recent proposal. This condition conjectures the existence of a semilocal bound on negative energy along null geodesics, which is expected to hold in semiclassical gravity. In this work, we show how the smeared null energy condition translates into theoretical constraints on NEC-violating cosmologies. Specifically, we derive the implied bounds on dark energy equation-of-state parameters and an inequality between the duration of a bouncing phase and the growth rate of the Hubble parameter at the bounce. In the case of dark energy, we identify the parameter space over which the smeared null energy condition is consistent with the recent constraints from the Dark Energy Spectroscopic Instrument (DESI).

28 pages, 7 figures; v2: minor changes and references added, matches published version

References in corpus (201)

• Observational Evidence from Supernovae for an Accelerating Universe and a Cosmological Constant
• Measurements of Omega and Lambda from 42 High-Redshift Supernovae
• The Cosmological Constant and Dark Energy
• Type Ia Supernova Discoveries at z>1 From the Hubble Space Telescope: Evidence for Past Deceleration and Constraints on Dark Energy Evolution
• A Phantom Menace? Cosmological consequences of a dark energy component with super-negative equation of state
• Exploring the Expansion History of the Universe
• Accelerating Universes with Scaling Dark Matter
• Phantom Energy and Cosmic Doomsday
• Dark Energy and the Accelerating Universe
• New Constraints on ${\Omega }_M$, ${\Omega }_{\Lambda }$, and w from an Independent Set of Eleven High-Redshift Supernovae Observed with HST
• Formation and evaporation of non-singular black holes
• The Pantheon+ Analysis: Cosmological Constraints
• Dark Energy Constraints from the Cosmic Age and Supernova
• Can the dark energy equation-of-state parameter w be less than -1?
• Properties of singularities in (phantom) dark energy universe
• DESI 2024 VI: Cosmological Constraints from the Measurements of Baryon Acoustic Oscillations
• Late-time cosmology in (phantom) scalar-tensor theory: dark energy and the cosmic speed-up
• The phantom menaced: constraints on low-energy effective ghosts
• Can dark energy evolve to the Phantom?
• Inflationary spacetimes are not past-complete
• On the Cosmological Implications of the String Swampland
• Starting the Universe: Stable Violation of the Null Energy Condition and Non-standard Cosmologies
• Cosmological Dynamics of Phantom Field
• Towards a Nonsingular Bouncing Cosmology
• Construction of Regular Black Holes in General Relativity
• Bouncing Cosmologies: Progress and Problems
• Black-bounce to traversable wormhole
• Crossing the Phantom Divide: Theoretical Implications and Observational Status
• Does backreaction enforce the averaged null energy condition in semiclassical gravity?
• A Critical Review of Classical Bouncing Cosmologies
• Null energy condition and superluminal propagation
• A Quantum Focussing Conjecture
• Phantom cosmologies
• Crossing the Phantom Divide: Dark Energy Internal Degrees of Freedom
• Phantom scalar dark energy as modified gravity: understanding the origin of the Big Rip singularity
• Observational constraints on low redshift evolution of dark energy: How consistent are different observations?
• DESI 2024 III: Baryon Acoustic Oscillations from Galaxies and Quasars
• Phenomenological parameterization of quintessence
• A parametric model for dark energy
• Cuscuton: A Causal Field Theory with an Infinite Speed of Sound
• Planck stars
• The 1965 Penrose singularity theorem
• Averaged Null Energy Condition from Causality
• Modular Hamiltonians for Deformed Half-Spaces and the Averaged Null Energy Condition
• The Null Energy Condition and its violation
• Energy's and amplitudes' positivity
• Proof of the Quantum Null Energy Condition
• Scalar fields, energy conditions, and traversable wormholes
• Generalized energy conditions in Extended Theories of Gravity
• Novel black-bounce spacetimes: wormholes, regularity, energy conditions, and causal structure
• Energy conditions in general relativity and quantum field theory
• Energy conditions in modified gravity
• On the viability of regular black holes
• Geodesically complete black holes
• Generic instabilities of non-singular cosmologies in Horndeski theory: a no-go theorem
• DESI 2024: Reconstructing Dark Energy using Crossing Statistics with DESI DR1 BAO data
• Stochastic Gravity: Theory and Applications
• The Effective Field Theory of nonsingular cosmology
• Quantum inequalities in two dimensional Minkowski spacetime
• Regular black holes with asymptotically Minkowski cores
• Gravitational vacuum polarization II: Energy conditions in the Boulware vacuum
• Quantum Energy Inequalities in two-dimensional conformal field theory
• Dark Energy in the Swampland
• Assessing observational constraints on dark energy
• Generalized Galileons: instabilities of bouncing and Genesis cosmologies and modified Genesis
• Cuscuton Cosmology: Dark Energy meets Modified Gravity
• Interpreting DESI's evidence for evolving dark energy
• Cuscuton and low energy limit of Horava-Lifshitz gravity
• Scant evidence for thawing quintessence
• A General Proof of the Quantum Null Energy Condition
• Gradient instability for w < -1
• Quintessential interpretation of the evolving dark energy in light of DESI
• Matter creation in a nonsingular bouncing cosmology
• Regular black holes and energy conditions
• Achronal averaged null energy condition
• Using non-DESI data to confirm and strengthen the DESI 2024 spatially-flat $w_0{w}_a$CDM cosmological parameterization result
• Gravitational vacuum polarization I: Energy conditions in the Hartle--Hawking vacuum
• Gravitational vacuum polarization IV: Energy conditions in the Unruh vacuum
• Holographic Proof of the Quantum Null Energy Condition
• Stability of Geodesically Complete Cosmologies
• Phantom Field with O(N) Symmetry in Exponential Potential
• Underdetermination of dark energy
• Extended Cuscuton: Formulation
• Hints of Nonminimally Coupled Gravity in DESI 2024 Baryon Acoustic Oscillation Measurements
• Cosmological parameter constraints for Horndeski scalar-tensor gravity
• Matching current observational constraints with nonminimally coupled dark energy
• Null energy conditions in quantum field theory
• Quintom cosmology and modified gravity after DESI 2024
• The Effective Field Theory of nonsingular cosmology: II
• Black hole collapse and bounce in effective loop quantum gravity
• An overview of what current data can (and cannot yet) say about evolving dark energy
• A Class of Minimally Modified Gravity Theories
• The state of the dark energy equation of state circa 2023
• The null energy condition and instability
• Hidden Negative Energies in Strongly Accelerated Universes
• Instabilities and the null energy condition
• Robustness of dark energy phenomenology across different parameterizations
• Positivity in the sky
• Evolution of cosmological perturbations and the production of non-Gaussianities through a nonsingular bounce: Indications for a no-go theorem in single field matter bounce cosmologies
• Quest for realistic non-singular black-hole geometries: Regular-center type
• Unbraiding the Bounce: Superluminality around the Corner
• When Matter Matters
• Proving the Achronal Averaged Null Energy Condition from the Generalized Second Law
• A theory of type-II minimally modified gravity
• A holographic proof of the averaged null energy condition
• A classical bounce: constraints and consequences
• Towards a Non-singular Paradigm of Black Hole Physics
• Generalized multi-Galileons, covariantized new terms, and the no-go theorem for non-singular cosmologies
• Quantifying Scalar Field Dynamics with DESI 2024 Y1 BAO measurements
• Singularity theorems from weakened energy conditions
• Minimally Modified Gravity: a Hamiltonian Construction
• Non-singular black holes and the Limiting Curvature Mechanism: A Hamiltonian perspective
• On the Null Energy Condition and Cosmology
• On wormholes with arbitrarily small quantities of exotic matter
• Quantum Energy Inequalities for the Non-Minimally Coupled Scalar Field
• Cuscuton Bounce
• Positivity Bounds on Dark Energy: When Matter Matters
• From Satisfying to Violating the Null Energy Condition
• Hamiltonian analysis of the cuscuton
• Cosmological constraints on dark energy in light of gravitational wave bounds
• Gravitational vacuum polarization III: Energy conditions in the (1+1) Schwarzschild spacetime
• Averaged null energy condition in spacetimes with boundaries
• Bouncing alternatives to inflation
• Unitary null energy condition violation in $P(X)$ cosmologies
• Quantum inequalities in two dimensional curved spacetimes
• Classification of dark energy models in the (w_0,w_a) plane
• Proof of the averaged null energy condition in a classical curved spacetime using a null-projected quantum inequality
• Phenomenology in type-I minimally modified gravity
• Local Modular Hamiltonians from the Quantum Null Energy Condition
• Cuscuton gravity as a classically stable limiting curvature theory
• Hawking's singularity theorem for $C^{1,1}$-metrics
• Caustics for Spherical Waves
• Symmetric Superfluids
• Singularity theorems for $C^1$-Lorentzian metrics
• The Penrose singularity theorem in regularity $C^{1,1}$
• Towards the Raychaudhuri Equation Beyond General Relativity
• The averaged null energy condition for general quantum field theories in two dimensions
• Quantum Null Energy Condition and its (non)saturation in 2d CFTs
• Inextendibility of spacetimes and Lorentzian length spaces
• The Hawking-Penrose singularity theorem for $C^{1,1}$-Lorentzian metrics
• Revisiting the cuscuton as a Lorentz-violating gravity theory
• The Quantum Null Energy Condition, Entanglement Wedge Nesting, and Quantum Focusing
• The Smeared Null Energy Condition
• Maximal extensions and singularities in inflationary spacetimes
• Horndeski in the Swampland
• Cosmological singularities in Bakry-Émery spacetimes
• VCDM and Cuscuton
• Rapidly Descending Dark Energy and the End of Cosmic Expansion
• Living with ghosts in Lorentz invariant theories
• Non-Singular Bounces Catalysed by Dark Energy
• Theory of Cosmological Perturbations with Cuscuton
• Energy Conditions in Jordan Frame
• A geometrical approach to degenerate scalar-tensor theories
• A review of Lorentzian synthetic theory of timelike Ricci curvature bounds
• Testing an oscillatory behavior of dark energy
• Exploring new physics in the late Universe's expansion through non-parametric inference
• Energy and Information Near Black Hole Horizons
• Cosmological singularity theorems and splitting theorems for N-Bakry-Emery spacetimes
• Averaged null energy condition in a classical curved background
• Proof of the quantum null energy condition for free fermionic field theories
• On the initial singularity and extendibility of flat quasi-de Sitter spacetimes
• Key drivers of the preference for dynamic dark energy
• The singularity theorems of General Relativity and their low regularity extensions
• Symmetric Scalars
• A singularity theorem based on spatial averages
• Spectrum of Cuscuton Bounce
• The Hawking-Penrose singularity theorem for $C^1$-Lorentzian metrics
• The Quantum Null Energy Condition in Curved Space
• A singularity theorem for Einstein-Klein-Gordon theory
• Perturbative unitarity and NEC violation in genesis cosmology
• Probing Cosmology with 92 Localized Fast Radio Bursts and DESI BAO
• The Return of the Singularities: Applications of the Smeared Null Energy Condition
• A critical appraisal of the singularity theorems
• Non-uniqueness of massless transverse-traceless graviton
• Upper and Lower Bounds on the Integrated Null Energy in Gravity
• Scalar-tensor gravitation and the Bakry-Emery-Ricci tensor
• Violations of the null convergence condition in kinematical transitions between singular and regular black holes, horizonless compact objects, and bounces
• Evading the theoretical no-go theorem for nonsingular bounces in Horndeski/Galileon cosmology
• A new derivation of singularity theorems with weakened energy hypotheses
• Probability distributions for the stress tensor in conformal field theories
• Production of non-gaussianities in a bouncing phase
• Massive gravity and the suppression of anisotropies and gravitational waves in a matter-dominated contracting universe
• Radiative stability and observational constraints on dark energy and modified gravity
• Non-perturbative materialization of ghosts
• A Renyi Quantum Null Energy Condition: Proof for Free Field Theories
• Enhance Primordial Black Hole Abundance through the Non-linear Processes around Bounce Point
• Model Independent Analysis of Supernova Data, Dark Energy, Trans-Planckian Censorship and the Swampland
• Saturation of the Quantum Null Energy Condition in Far-From-Equilibrium Systems
• On Coupling NEC-Violating Matter to Gravity
• Kerr-NUT-de Sitter as an Inhomogeneous Non-Singular Bouncing Cosmology
• Theories with limited extrinsic curvature and a nonsingular anisotropic universe
• Averaged Energy Conditions and Bouncing Universes
• Boosted dark matter from a phantom fluid
• General background conditions for K-bounce and adiabaticity
• Singularity theorems in the effective field theory for quantum gravity at second order in curvature
• Cosmological singularity theorems for $f(R)$ gravity theories
• Cuscuton Bounce Beyond the Linear Regime: Bispectrum and Strong Coupling Constraints
• Can Baby Universe Absorption Explain Dark Energy?
• Hawking-type singularity theorems for worldvolume energy inequalities
• Wormhole restrictions from quantum energy inequalities
• Delicate curvature bounces in the no-boundary wave function and in the late universe

Cited by in corpus (4)

• Updated observational constraints on $\varphi$CDM dynamical dark energy cosmological models
• Phase space analysis of an exponential model in $f(Q)$ gravity including linear dark-sector interactions
• Time Dependent String Compactification: Towards Bouncing Cosmology
• Scale without Conformal Invariance in bottom-up Holography