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Thin-shell wormholes: Linearization stability

General Relativity and Quantum Cosmology · Submitted 30 Jun 1995 · 9 references

Pith's verdict: A clean, correct short note that turns thin-shell wormhole stability into a one-parameter criterion on the equation of state; the algebra holds and the caveats are stated, not hidden.

T0 · AI review

How this review was made: An AI referee (selfhosted/deepseek-v4.1-flash) read the paper on November 11, 2026 and answered a fixed list of questions about it. T0 is the starting level every paper gets. The levels describe how deeply Pith has checked the paper, never the authors.

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  4. T3 Formal statement The claims written out in a formal math language a computer can read.
  5. T4 Proof Those claims proved, and the proof checked by computer.

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arXiv IDgr-qc/9506083 (version 1)
Pith IDSTKG5QIK, Pith's permanent record of this paper and its review
CitationEric Poisson, Matt Visser (Washington University). "Thin-shell wormholes: Linearization stability." arXiv:gr-qc/9506083 (1995). https://pith.science/paper/STKG5QIK
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The paper

The paper claims

Spherically symmetric thin-shell wormholes are linearly stable only if the throat matter has an unusual equation of state: for throats larger than three times the mass, stability requires the squared sound-speed parameter to be negative.

The reading

A thin-shell wormhole is a toy model of a traversable wormhole built by cutting two copies of the Schwarzschild black-hole spacetime and gluing them together along a spherical surface. The seam is the wormhole throat, and it must carry exotic matter with negative energy density to hold the geometry open. Once you specify how that surface matter responds to compression, its equation of state, the Einstein equations determine how the throat radius moves. This paper asks a narrower question: if the wormhole sits at rest at some radius, is that rest state stable? The authors perturb the throat radius slightly, expand the effective potential to second order, and find that stability is controlled by a single number, beta-squared, defined as the derivative of surface pressure with respect to surface energy density. The answer is a clean inequality relating beta-squared to the throat radius in units of the wormhole mass. The result is counterintuitive. If beta is interpreted as a sound speed and restricted to the ordinary range between zero and the speed of light, the inequality can never be satisfied: every such wormhole is unstable. Stability is possible only in two pockets of parameter space, one requiring a large negative beta-squared at or below minus one half, and one requiring a very large positive beta-squared above about 3.23 with the throat radius pinned near twice the mass. The authors point out that known exotic sources such as the Casimir vacuum and false vacuum have beta-squared equal to minus one, so the negative pocket is not empty. They also caution that beta need not literally be a sound speed, since no microphysical model of the exotic matter exists.
Extended reading notes

Core claim

The paper's load-bearing assertion is Eq. (29): a spherically symmetric thin-shell wormhole is linearly stable against radial perturbations if and only if 2M/a0 + (M^2/a0^2)/(1-2M/a0) + (1+2*beta0^2)(1-3M/a0) < 0, where beta0^2 = dp/dsigma evaluated at the static solution. The consequence stated in Section IV is that for a0 > 3M stability requires beta0^2 < 0, so a wormhole whose surface matter has a conventional sound speed (0 < beta0 <= 1) is always unstable. If correct, this is a general no-go for stabilizing thin-shell wormholes with ordinary matter.

Load-bearing premise

The derivation assumes the perturbed shell still obeys a barotropic equation of state p = p(sigma) with a fixed beta^2 = dp/dsigma, so that sigma can be written as a function of the throat radius alone (Section III, Eq. 16 and the paragraph beginning 'If we choose a particular equation of state'). It also assumes spherical symmetry and that the throat radius is the only dynamical degree of freedom, with Schwarzschild geometry unchanged on either side. If the surface matter is not barotropic, or if non-spherical or radiative modes grow faster, the stability conclusion need not hold.

Original abstract

The class of spherically-symmetric thin-shell wormholes provides a particularly elegant collection of exemplars for the study of traversable Lorentzian wormholes. In the present paper we consider linearized (spherically symmetric) perturbations around some assumed static solution of the Einstein field equations. This permits us to relate stability issues to the (linearized) equation of state of the exotic matter which is located at the wormhole throat.

The compiled record

The paper's own sentences, arranged, kept beside the review and separate from it. 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.

Compiled by classifier-1.13-20260917 via OpenRouter, question bank abstract-p1-20260923, 2026-09-23: 1 request, 2,944 input tokens, $0.0001 reported.

What the abstract itself states, as probabilities: claims first 0.03 · states limitation 0.20 · human participants 0.01 · controlled comparison 0.05 · randomized assignment 0.01 · states quantitative result 0.03 · compares with prior results 0.05 · mentions code or data availability 0.01.

The abstract, sentence by sentence

arXiv listing abstract v1. Results and the main claim are underlined; .

The class of spherically-symmetric thin-shell wormholes provides a particularly elegant collection of exemplars for the study of traversable Lorentzian wormholes. In the present paper we consider linearized (spherically symmetric) perturbations around some assumed static solution of the Einstein field equations. This permits us to relate stability issues to the (linearized) equation of state of the exotic matter which is located at the wormhole throat.

background contribution method result interpretation main claim

What the classifier reports for each sentence. The number is the probability it gave the label.
#sentencerolethe authors' own workstates the main conclusionstrength
s0 The class of spherically-symmetric thin-shell wormholes provides a particularly elegant collection of exemplars for the study of traversable Lorentzian wormholes. background 1.00 0.06 0.03 asserted 1.00
s1 In the present paper we consider linearized (spherically symmetric) perturbations around some assumed static solution of the Einstein field equations. contribution 0.68 0.90 0.04 asserted 0.94
s2 This permits us to relate stability issues to the (linearized) equation of state of the exotic matter which is located at the wormhole throat. interpretation 0.31 0.77 0.16 asserted 0.92

What kind of paper the classifier reports this is: theoretical result 1.00 · evidence from proof or derivation 1.00.

What was examined, and what was not

sources read
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  • figures and tables
  • references and citing sentences
  • relations to other papers
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  • P abstract
not run
  • S sections
  • T body sentences
  • C citations
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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

Figures
Figure 1. FIG. 1. Regions of stability: Traversable wormholes in

Figures reproduced from arXiv:gr-qc/9506083 by the authors.

References
How later papers used it

69 later papers cite it

Evidence: substantial. 58 of the citing papers share no author with it, and 11 of those carry a confident label from Pith's citation classifier.

Pith read 21 of the 121 citing sentences, choosing only those whose citation markers point at this paper alone, and wrote the paraphrases from them. The summary, the counts, the evidence level, the links and the quotes come from code; the summary counts the papers listed below. A later paper is listed under a label when Pith's citation classifier gives one of its sentences that label at probability 0.8 or more (0.95 for support), Pith's reading finds that the citing paper itself did it, and a second check confirms the paraphrase against the sentence. This section lists uses only. It does not list criticism or disagreement, so their absence here says nothing about how the paper has been received. Papers that share an author with this one are listed apart, under "By the same authors". A quote is the citing authors' own sentence, shown when their paper's licence is CC BY, CC BY-SA or CC0. JSON

Builds on it 1 of 2 papers with this label · 1 by the same authors

By the same authors

Uses its method or tool 4 of 9 papers with this label
Compares with it 1 of 8 papers with this label
How the literature uses it

56 arXiv papers cite this in 104 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 citing it · 51 sentences without a confident label

Builds on it 2 papers
Uses its method or tool 7 papers
Compares with it 7 papers
Cites it as support 1 paper
Cites it as background 27 papers

Discussion

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