Is the squeezing of relic gravitational waves produced by inflation detectable?

Bruce Allen (U. of Wisconsin - Milwaukee); Eanna Flanagan (Cornell University); Frascati); Maria Alessandra Papa (INFN

RECORD

Is the squeezing of relic gravitational waves produced by inflation detectable?

Bruce Allen (U. of Wisconsin - Milwaukee), Eanna Flanagan (Cornell University), Maria Alessandra Papa (INFN, Frascati)

General Relativity and Quantum Cosmology · Submitted 15 Jun 1999

abstract compiled · 2026-09-23 · no language-model review

The authors' main claim Sadly, the answer appears to be "no": an experiment which could distinguish the non-stationary behavior would have to last approximately the age of the Universe at the time of measurement.

how it is stated · asserted 0.59 read the record →

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arXiv IDgr-qc/9906054 (version 2)

Pith IDFWMSW4MX, Pith's permanent record of this paper and its review

CitationBruce Allen (U. of Wisconsin - Milwaukee), Eanna Flanagan (Cornell University), Frascati), Maria Alessandra Papa (INFN. "Is the squeezing of relic gravitational waves produced by inflation detectable?." arXiv:gr-qc/9906054 (1999). https://pith.science/paper/FWMSW4MX

Claim paper

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.

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Compiled by classifier-1.13-20260917 via OpenRouter, question bank abstract-p1-20260923, 2026-09-23: 1 request, 5,525 input tokens, $0.0002 reported.

What the abstract itself states, as probabilities: claims first 0.05 · states limitation 0.82 · human participants 0.02 · controlled comparison 0.11 · randomized assignment 0.01 · states quantitative result 0.27 · compares with prior results 0.56 · mentions code or data availability 0.02.

The abstract, sentence by sentence

arXiv listing abstract v2. Results and the main claim are underlined; show every role.

Grishchuk has shown that the stochastic background of gravitational waves produced by an inflationary phase in the early Universe has an unusual property: it is not a stationary Gaussian random process. Due to squeezing, the phases of the different waves are correlated in a deterministic way, arising from the process of parametric amplification that created them. The resulting random process is Gaussian but non-stationary. This provides a unique signature that could in principle distinguish a background created by inflation from stationary stochastic backgrounds created by other types of processes. We address the question: could this signature be observed with a gravitational wave detector? Sadly, the answer appears to be "no": an experiment which could distinguish the non-stationary behavior would have to last approximately the age of the Universe at the time of measurement. This rules out direct detection by ground and space based gravitational wave detectors, but not indirect detections via the electromagnetic Cosmic Microwave Background Radiation (CMBR).

background contribution method result interpretation main claim

What the classifier reports for each sentence. The number is the probability it gave the label.
#	sentence	role	the authors' own work	states the main conclusion	strength
s0	Grishchuk has shown that the stochastic background of gravitational waves produced by an inflationary phase in the early Universe has an unusual property: it is not a stationary Gaussian random process.	background 1.00	0.03	0.03	asserted 1.00
s1	Due to squeezing, the phases of the different waves are correlated in a deterministic way, arising from the process of parametric amplification that created them.	background 0.88	0.07	0.03	asserted 1.00
s2	The resulting random process is Gaussian but non-stationary.	background 0.54	0.10	0.04	asserted 1.00
s3	This provides a unique signature that could in principle distinguish a background created by inflation from stationary stochastic backgrounds created by other types of processes.	interpretation 0.63	0.10	0.07	hedged possibility 0.99
s4	We address the question: could this signature be observed with a gravitational wave detector?	contribution 0.53	0.23	0.03	hedged possibility 0.69
s5	Sadly, the answer appears to be "no": an experiment which could distinguish the non-stationary behavior would have to last approximately the age of the Universe at the time of measurement.	result 0.95	0.66	0.83	asserted 0.59
s6	This rules out direct detection by ground and space based gravitational wave detectors, but not indirect detections via the electromagnetic Cosmic Microwave Background Radiation (CMBR).	interpretation 0.78	0.51	0.27	asserted 0.98

What kind of paper the classifier reports this is: theoretical result 0.90 · evidence from argument 0.52.

What was examined, and what was not

sources read

arXiv listing abstract v2

not examined

full text
figures and tables
references and citing sentences
relations to other papers

levels run

P abstract

not run

S sections
T body sentences
C citations
R cross-paper relations

Every quoted sentence on this record is the authors'. Every label is from Pith's closed vocabulary, with the probability shown beside it. Every number in the measurements table is the authors', checked by code. Record as JSON

The paper

Original abstract

Grishchuk has shown that the stochastic background of gravitational waves produced by an inflationary phase in the early Universe has an unusual property: it is not a stationary Gaussian random process. Due to squeezing, the phases of the different waves are correlated in a deterministic way, arising from the process of parametric amplification that created them. The resulting random process is Gaussian but non-stationary. This provides a unique signature that could in principle distinguish a background created by inflation from stationary stochastic backgrounds created by other types of processes. We address the question: could this signature be observed with a gravitational wave detector? Sadly, the answer appears to be "no": an experiment which could distinguish the non-stationary behavior would have to last approximately the age of the Universe at the time of measurement. This rules out direct detection by ground and space based gravitational wave detectors, but not indirect detections via the electromagnetic Cosmic Microwave Background Radiation (CMBR).

Human review

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References

Forward citations

Cited by 4 Pith papers

Reviewed papers in the Pith corpus that reference this work. Sorted by Pith novelty score. Full citation record

Graviton-induced which-path decoherence in matter-wave interferometry
gr-qc 2026-07 conditional novelty 6.0 of 10

Radiative graviton decoherence in matter-wave interferometers is shown to be far below detection, even with strongly squeezed inflationary graviton states.
Probing the early universe with inflationary gravitational waves
astro-ph 2005-12 conditional novelty 6.0 of 10

A three-factor gravitational-wave transfer function separates inflationary information from post-inflationary effects, including dark energy, the horizon-crossing equation of state, and damping by free-streaming particles.
The Challenge of Detecting Quantum Nature of Gravitational Waves
hep-ph 2026-08 accept novelty 5.0 of 10

Squeezing of gravitational waves at the source is not an observable resource after projection onto a detector mode; squeezing the detector can in principle witness quantum gravity, but the tiny coupling makes the sign...
Relating gravitational wave constraints from primordial nucleosynthesis, pulsar timing, laser interferometers, and the CMB: implications for the early universe
astro-ph 2007-08 accept novelty 5.0 of 10

A master equation connects the CMB tensor-to-scalar ratio to the high-frequency gravitational-wave spectrum, turning future detections into constraints on the early universe's equation of state.

How the literature uses it

13 arXiv papers cite this in 23 sentences

Each citing sentence is taken from the citing paper's LaTeX source and typed by Pith's classifier. A label appears at probability 0.8 or more (0.95 for support), a contest at 0.7 or more; the quoted words are the citing authors'. How each label was checked · JSON

Papers whose main result relates to this one's

Found among the papers closest to this one by title and main claim. Pith's classifier compared each pair's main results and a second model family confirmed the relation; checked against two further families, shown conflicts agreed 118 times in 120 and shown same results 218 times in 239. The quoted sentence is the other paper's main claim.

States a conflicting result 1 paper

It is shown that the expected amplitudes and specific correlation properties of the relic (squeezed) gravitational wave background may allow the registration of the relic gravitational waves by the first generation of sensitive gravity-wave detectors.

The Detectability of Relic (Squeezed) Gravitational Waves by Laser Interferometers · 0.88

Papers citing it · 20 sentences without a confident label

Compares with it 1 paper

The claim given in this subsection is very close to what was discussed in Ref. [ref] .

The Challenge of Detecting Quantum Nature of Gravitational Waves · Two-Mode Squeezed State of Inflationary Gravitational Waves · 0.93

Cites it as support 1 paper

This means that the inflationary GWs have a standing-wave nature [ref] .

Antipodal Angular Correlations of Inflationary Stochastic Gravitational Wave Background · Traveling/Standing-wave nature of stochastic gravitational wave background · 0.96

Cites it as background 1 paper

The classicalization of a quantum perturbation has been a subject of active research (see for example [ref] ).

Anharmonic Effects on the Squeezing of Axion Perturbations · Introduction · 1.00

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