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arxiv: 2606.11413 · v1 · pith:JZM37R4Mnew · submitted 2026-06-09 · 🌀 gr-qc · astro-ph.HE· hep-th

Linearized stability of T-duality quantum-inspired thin-shell wormholes

Francisco S.N. Lobo , Manuel E. Rodrigues This is my paper

Pith reviewed 2026-06-27 12:06 UTC · model grok-4.3

classification 🌀 gr-qc astro-ph.HEhep-th
keywords thin-shell wormholesT-dualitylinearized stabilityregular spacetimequantum correctionsexotic matterwormhole stability
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The pith

T-duality regularization yields a window of unconditional stability for thin-shell wormholes at intermediate radii

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The paper constructs thin-shell wormholes by gluing two copies of a T-duality regularized spacetime whose central singularity is replaced by a smooth core set by the fundamental length l0. Static configurations are examined through the Israel junction conditions to obtain the surface stresses, which satisfy the null and strong energy conditions when the throat radius is sufficiently large. A linearized stability analysis against radial perturbations then identifies three regimes: instability near the minimum allowed radius, a region of unconditional stability when the throat sits near l0 because the geometric stability threshold turns negative, and Schwarzschild-like behavior at large radii that again demands a stiff equation of state. The central insight is that the quantum length scale l0 is not only a regulator but the parameter that opens a stability window absent from the classical thin-shell case.

Core claim

In the T-duality quantum-corrected spacetime the thin-shell wormhole admits a region of unconditional stability for intermediate throat radii a approximately equal to the fundamental length l0, where the geometric stability threshold becomes negative so that any convex surface mass function yields stability, in contrast to the classical Schwarzschild thin-shell wormhole which requires a specific equation of state.

What carries the argument

The effective potential for small radial perturbations obtained from the second variation of the junction-condition energy equation, whose second derivative at equilibrium depends on the T-duality metric functions and surface stresses.

Load-bearing premise

The T-duality regularized metric with length scale l0 is taken as the exact background geometry and the thin-shell junction conditions are assumed to produce the stated surface stresses and stability equation.

What would settle it

A direct evaluation of the second derivative of the effective potential for the T-duality metric that shows the stability threshold remains positive for all radii near l0 would falsify the unconditional-stability window.

Figures

Figures reproduced from arXiv: 2606.11413 by Francisco S.N. Lobo, Manuel E. Rodrigues.

Figure 1
Figure 1. Figure 1: The solid contour surface depicts the geometric [PITH_FULL_IMAGE:figures/full_fig_p009_1.png] view at source ↗
read the original abstract

Wormholes that are traversable in principle offer fascinating insights into general relativity, yet they typically require exotic matter and suffer from stability issues. We construct a thin-shell wormhole by gluing two copies of a quantum-corrected, regular spacetime obtained from string T-duality. This regularisation replaces the classical curvature singularity with a smooth core and introduces a fundamental length scale $l_0$. For the static configuration, we derive the surface stresses and show that, unlike the Schwarzschild case, the null and strong energy conditions can be satisfied for sufficiently large throat radii. A linearised stability analysis reveals a rich landscape: close to the minimum allowed throat radius the configuration is unstable; at intermediate radii ($a \sim l_0$) the geometric stability threshold becomes negative, yielding a window of \emph{unconditional stability} where any convex surface mass function suffices; at large radii the wormhole recovers Schwarzschild-like behaviour and stability requires a stiff equation of state. The T-duality scale $l_0$ is thus not merely a regulariser but a key physical parameter that opens a novel region of unconditional stability absent in classical thin-shell wormholes. Our results suggest that quantum-gravity-motivated modifications can simultaneously cure singularities and make traversable wormholes dynamically viable, providing new targets for gravitational-wave astronomy and theoretical studies of exotic compact objects.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit. Tearing a paper down is the easy half of reading it; the pith above is the substance, this is the friction.

Referee Report

1 major / 2 minor

Summary. The paper constructs thin-shell wormholes by gluing two copies of a T-duality-regularized spacetime (with fundamental length l0 replacing the classical singularity). It derives the surface energy density and pressure via Israel junction conditions, shows that the null and strong energy conditions can be satisfied for sufficiently large throat radii (unlike the Schwarzschild case), and performs a linearized stability analysis around the static configuration. The analysis identifies three regimes: instability near the minimum allowed throat radius, a window of unconditional stability at intermediate radii a ∼ l0 (where the geometric stability threshold is negative, so any convex surface mass function suffices), and Schwarzschild-like behavior at large radii requiring a stiff equation of state. The T-duality scale l0 is presented as both a regularizer and the parameter enabling the novel stability window.

Significance. If the derivations hold, the result is significant: it shows that a quantum-gravity-motivated regularization can simultaneously eliminate the curvature singularity and open a regime of unconditional dynamical stability for thin-shell wormholes that is absent in the classical case. This provides concrete new targets for gravitational-wave astronomy and studies of exotic compact objects, with the stability threshold arising as a geometric quantity rather than a fitted parameter.

major comments (1)
  1. [Linearized stability analysis] Linearized stability analysis (the section deriving the effective potential and its second derivative): the central claim of an unconditional-stability window rests on the geometric stability threshold becoming negative for a ∼ l0. The explicit metric functions f(r) of the T-duality spacetime, the resulting extrinsic curvatures from the junction conditions, and the differentiated conservation/dynamical equation must be displayed (including all terms involving l0) so that the sign change can be verified independently; an algebraic sign error, omitted l0-derivative term, or incorrect identification of the background radius a0 would eliminate the negativity and collapse the window to the classical case.
minor comments (2)
  1. The abstract summarizes the outcome but the manuscript should include all intermediate expressions for the surface stresses σ(a), p(a) and the stability threshold to ensure reproducibility.
  2. Notation for the T-duality scale l0 and the throat radius a should be introduced with a clear statement of their relative scale in the static background.

Simulated Author's Rebuttal

1 responses · 0 unresolved

We thank the referee for the careful reading of our manuscript and for highlighting the importance of explicit verification of the stability threshold. We address the single major comment below and will incorporate the requested details in a revised version.

read point-by-point responses

  1. Referee: Linearized stability analysis (the section deriving the effective potential and its second derivative): the central claim of an unconditional-stability window rests on the geometric stability threshold becoming negative for a ∼ l0. The explicit metric functions f(r) of the T-duality spacetime, the resulting extrinsic curvatures from the junction conditions, and the differentiated conservation/dynamical equation must be displayed (including all terms involving l0) so that the sign change can be verified independently; an algebraic sign error, omitted l0-derivative term, or incorrect identification of the background radius a0 would eliminate the negativity and collapse the window to the classical case.

    Authors: We agree that the explicit expressions are required for independent verification. In the revised manuscript we will add: (i) the complete T-duality metric function f(r) with all l0 terms, (ii) the full Israel-junction expressions for the extrinsic curvature components K^θ_θ and K^τ_τ evaluated at the throat (including every derivative with respect to l0), and (iii) the differentiated conservation equation that yields the effective potential V(a) together with its second derivative at the static radius a0. These additions will make the sign change of the geometric stability threshold at a ∼ l0 directly verifiable and will confirm that the negativity arises from the quantum-correction terms rather than from an algebraic error or omitted derivative. The background radius a0 is identified unambiguously as the static solution of the junction conditions. revision: yes

Circularity Check

0 steps flagged

No circularity: stability threshold derived from junction conditions on given metric

full rationale

The derivation proceeds from the T-duality-regularized metric (taken as input) through explicit Israel junction conditions to surface stresses σ(a), p(a), then to the linearized equation of motion whose coefficient (the geometric stability threshold) is computed by differentiation. No step equates a fitted parameter to a prediction, renames a known result, or reduces the central claim to a self-citation chain. The sign change at a ∼ l0 is an algebraic outcome of the explicit functions, not imposed by definition. This is the normal case of a self-contained calculation against external benchmarks.

Axiom & Free-Parameter Ledger

0 free parameters · 2 axioms · 0 invented entities

The construction rests on the T-duality-regularized metric (standard in the cited string-theory literature) and the thin-shell junction formalism of general relativity; l0 is introduced as an external fundamental scale rather than fitted; no new entities are postulated beyond the regularized geometry already present in prior T-duality papers.

axioms (2)
  • domain assumption The T-duality-regularized spacetime is a valid solution of the effective string equations and can be glued across a thin shell using the standard Israel junction conditions.
    Invoked implicitly when the authors state they glue two copies and derive surface stresses.
  • domain assumption Linearized perturbations around the static throat capture the dynamical stability of the configuration.
    Standard assumption in thin-shell wormhole stability analyses; stated in the abstract as the method used.

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Forward citations

Cited by 1 Pith paper

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

  1. Thermodynamics of thin-shell wormholes

    gr-qc 2026-06 unverdicted novelty 5.0

    The paper derives a generalized first law for thin-shell wormholes showing entropy conservation for isolated transparent shells and flux-dependent entropy change when bulk matter crosses the throat.

Reference graph

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