RECORD
Gravitons and Lightcone Fluctuations
General Relativity and Quantum Cosmology · Submitted 31 Oct 1994
abstract compiled · 2026-09-23 · no language-model review
The authors' main claim It is shown that when the various two-point functions of a quantized field are averaged over the metric fluctuations, the lightcone singularity disappears for distinct points.
The compiled record
The paper's own sentences, arranged. Each label is drawn from a closed vocabulary; the number beside it is the probability the classifier gave that label. Numbers in the tables are the authors', checked by code. No sentence in this record was written by a model.
Open the compiled record
The abstract, sentence by sentence
Gravitons in a squeezed vacuum state, the natural result of quantum creation in the early universe or by black holes, will introduce metric fluctuations. These metric fluctuations will introduce fluctuations of the lightcone. It is shown that when the various two-point functions of a quantized field are averaged over the metric fluctuations, the lightcone singularity disappears for distinct points. The metric averaged functions remain singular in the limit of coincident points. The metric averaged retarded Green's function for a massless field becomes a Gaussian which is nonzero both inside and outside of the classical lightcone. This implies some photons propagate faster than the classical light speed, whereas others propagate slower. The possible effects of metric fluctuations upon one-loop quantum processes are discussed and illustrated by the calculation of the one-loop electron self-energy.
background contribution method result interpretation main claim
| # | sentence | role | the authors' own work | states the main conclusion | strength |
|---|---|---|---|---|---|
| s0 | Gravitons in a squeezed vacuum state, the natural result of quantum creation in the early universe or by black holes, will introduce metric fluctuations. | background 0.92 | 0.15 | 0.06 | asserted 0.97 |
| s1 | These metric fluctuations will introduce fluctuations of the lightcone. | result 0.52 | 0.31 | 0.08 | asserted 0.99 |
| s2 | It is shown that when the various two-point functions of a quantized field are averaged over the metric fluctuations, the lightcone singularity disappears for distinct points. | result 0.96 | 0.88 | 0.51 | asserted 1.00 |
| s3 | The metric averaged functions remain singular in the limit of coincident points. | result 0.99 | 0.83 | 0.10 | asserted 1.00 |
| s4 | The metric averaged retarded Green's function for a massless field becomes a Gaussian which is nonzero both inside and outside of the classical lightcone. | result 1.00 | 0.85 | 0.34 | asserted 1.00 |
| s5 | This implies some photons propagate faster than the classical light speed, whereas others propagate slower. | interpretation 1.00 | 0.67 | 0.24 | asserted 0.62 |
| s6 | The possible effects of metric fluctuations upon one-loop quantum processes are discussed and illustrated by the calculation of the one-loop electron self-energy. | contribution 0.95 | 0.82 | 0.06 | hedged possibility 0.49 |
What was examined, and what was not
- arXiv listing abstract v1
- full text
- figures and tables
- references and citing sentences
- relations to other papers
- P abstract
- S sections
- T body sentences
- C citations
- R cross-paper relations
The paper
Original abstract
Gravitons in a squeezed vacuum state, the natural result of quantum creation in the early universe or by black holes, will introduce metric fluctuations. These metric fluctuations will introduce fluctuations of the lightcone. It is shown that when the various two-point functions of a quantized field are averaged over the metric fluctuations, the lightcone singularity disappears for distinct points. The metric averaged functions remain singular in the limit of coincident points. The metric averaged retarded Green's function for a massless field becomes a Gaussian which is nonzero both inside and outside of the classical lightcone. This implies some photons propagate faster than the classical light speed, whereas others propagate slower. The possible effects of metric fluctuations upon one-loop quantum processes are discussed and illustrated by the calculation of the one-loop electron self-energy.
Human review
References
How the literature uses it
24 arXiv papers cite this in 45 sentences
Papers citing it · 35 sentences without a confident label
Contests it 1 paper
-
If we include the second order term, $σ_2$, then Eq. ([ref]) is modified to become [equation] We notice that these two last equations appear misprinted in Ref. [ref] .
An Analog Model for Quantum Lightcone Fluctuations in Nonlinear Optics · Lightcone Fluctuations in Linearized Quantum Gravity · contest 0.77
Compares with it 3 papers
-
In particular, in [ref] without explicitly calculating the commutator in perturbation theory, Ford correctly assumes that the retarded propagator is delta-like supported on the modified lightcone $x⃗^ 2 = t^2 + κt O(x)$ (in his notation, $κt O(x) = σ_1$ and, in his units, $κ=1/2$).
Probabilistic Causality from Graviton Fluctuations · Comparison with the results of L. H. Ford · 0.80
-
A similar light-cone smearing was discussed for quantized gravitons [ref] , while here it is induced by the quantum matter source.
Quantum Matter Makes Lightcones Quantum · Light-cone Smearing and UV cutoff · 0.84
-
For causality, it implies that we lose our standard definitions of causal behavior, even if the asymptotic observers are in regions which are flat enough to apply Minkowski definitions locally [We remark that the discussion of lightcone fluctuations here differ from those developed by Ford and collaborators, see for instance Refs. [ref] .
Causality and gravity · The lightcone is not a quantum gravity concept · 0.85
Cites it as support 1 paper
-
This feature and the fact that lightcones are ill-defined in quantum gravity, as demonstrated in some low-energy calculations [ref] , have been employed to argue that uncertainty in the causal structure of field theory is inevitable when taking into account quantum-gravity effects [ref] .
Quantum gravity phenomenology from the perspective of quantum general relativity and quadratic gravity · Causality violation in quadratic gravity · 0.96
Cites it as background 4 papers
-
Such stochastic models of gravity lead to observable consequences in principle, ranging from light cone fluctuations [ref] to induced decoherence for matter propagating in such fluctuating space times [ref] .
Neutrino oscillations in a stochastic model for space-time foam · Introduction · 0.91
-
Related models were presented in Ref. [ref] , as an analog model for semiclassical gravity, and in Ref. [ref] , as a model for the lightcone fluctuations expected in quantum gravity [ref] .
Vacuum Lightcone Fluctuations in a Dielectric · Introduction · 0.85
-
Other interesting prior work includes Refs. [ref] .
Bound on Quantum Fluctuations in Gravitational Waves from LIGO-Virgo · Introduction · 0.97
Discussion
Know something about this paper? Leave a comment, or highlight any passage above to comment on it.