Proves equivalence of redundant Goldstone and adjoint-matter formulations of SK EFTs for non-Abelian symmetries and extends both to all orders in ħω/T while classifying invariant kernels under DKMS and unitarity.
Null energy condition and superluminal propagation
5 Pith papers cite this work. Polarity classification is still indexing.
5
Pith papers citing it
abstract
We study whether a violation of the null energy condition necessarily implies the presence of instabilities. We prove that this is the case in a large class of situations, including isotropic solids and fluids relevant for cosmology. On the other hand we present several counter-examples of consistent effective field theories possessing a stable background where the null energy condition is violated. Two necessary features of these counter-examples are the lack of isotropy of the background and the presence of superluminal modes. We argue that many of the properties of massive gravity can be understood by associating it to a solid at the edge of violating the null energy condition. We briefly analyze the difficulties of mimicking $\dot H>0$ in scalar tensor theories of gravity.
verdicts
UNVERDICTED 5representative citing papers
Affine ANEC obstructs non-static flat and open FRW from being null geodesically complete while ANEC-satisfying, but allows explicit scalar-field realizations for closed FRW with NEC-respecting matter.
Phantom Chaplygin gas forces the Einstein-frame lapse to change sign smoothly while the causal-frame lapse stays positive, yielding a robust non-singular bounce even with extra matter.
A covariant model of Dirac fermions with an extra Planck-derived term yields the same Einstein-equation collapse as ordinary GR yet permits numerical trajectories that escape the black hole.
Bouncing solutions in quadratic curvature gravity with a scalar field satisfy null, weak, and dominant energy conditions but violate the strong one when using the scalar-field energy-momentum tensor, while all four conditions are violated near the bounce in the effective tensor formulation.
citing papers explorer
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Schwinger-Keldysh effective theory of charge transport: redundancies and systematic $\omega/T$ expansion
Proves equivalence of redundant Goldstone and adjoint-matter formulations of SK EFTs for non-Abelian symmetries and extends both to all orders in ħω/T while classifying invariant kernels under DKMS and unitarity.
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Affine ANEC selects the closed FRW branch for geodesically complete cosmology
Affine ANEC obstructs non-static flat and open FRW from being null geodesically complete while ANEC-satisfying, but allows explicit scalar-field realizations for closed FRW with NEC-respecting matter.
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Geodesic completion of big bangs from emergent geometry
Phantom Chaplygin gas forces the Einstein-frame lapse to change sign smoothly while the causal-frame lapse stays positive, yielding a robust non-singular bounce even with extra matter.
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Classical limit for Dirac fermions with modified action in the presence of the black hole
A covariant model of Dirac fermions with an extra Planck-derived term yields the same Einstein-equation collapse as ordinary GR yet permits numerical trajectories that escape the black hole.
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Energy conditions of bouncing solutions in quadratic curvature gravity coupled with a scalar field
Bouncing solutions in quadratic curvature gravity with a scalar field satisfy null, weak, and dominant energy conditions but violate the strong one when using the scalar-field energy-momentum tensor, while all four conditions are violated near the bounce in the effective tensor formulation.