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arxiv: 2606.19049 · v1 · pith:NZV7GPZEnew · submitted 2026-06-17 · ✦ hep-th

Instability of 5D Gauss-Bonnet black branes

Alex Buchel , Raphael E. Hoult , Pavel Kovtun This is my paper

Pith reviewed 2026-06-26 20:04 UTC · model grok-4.3

classification ✦ hep-th
keywords Gauss-Bonnetblack branesAdS5instabilityconformal collider boundscausalityholography
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The pith

Gauss-Bonnet black branes in five-dimensional anti-de Sitter gravity are unstable outside the coupling range set by conformal collider bounds.

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

The paper establishes that five-dimensional Gauss-Bonnet black branes in anti-de Sitter space become unstable for values of the Gauss-Bonnet coupling that lie outside the range permitted by conformal collider bounds. It further shows that the unstable modes in the bulk are related to modes that would violate causality in the boundary theory through a phase rotation applied to complex boundary momentum. A sympathetic reader would care because this result ties the gravitational stability of the bulk solution directly to consistency conditions derived from the dual field theory. The connection implies that the collider bounds serve as the precise boundary separating stable and unstable regimes.

Core claim

Gauss-Bonnet black branes in five-dimensional anti-de Sitter gravity are unstable when the Gauss-Bonnet coupling falls outside the range allowed by the conformal collider bounds. The unstable modes and the boundary causality violating modes are connected by a phase rotation of complex boundary momentum.

What carries the argument

The phase rotation of complex boundary momentum that maps unstable bulk modes to boundary causality-violating modes.

Load-bearing premise

The conformal collider bounds define the exact threshold for stability and that the phase rotation continues to relate the modes under the complete dynamical evolution.

What would settle it

A calculation showing the absence of unstable modes for a Gauss-Bonnet coupling value outside the collider bounds would falsify the instability claim.

read the original abstract

We show that Gauss-Bonnet black branes in five-dimensional anti-de Sitter gravity are unstable when the Gauss-Bonnet coupling falls outside the range allowed by the conformal collider bounds. The unstable modes and the boundary causality violating modes are connected by a phase rotation of complex boundary momentum.

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 / 0 minor

Summary. The manuscript claims that five-dimensional Gauss-Bonnet black branes in anti-de Sitter gravity are unstable when the Gauss-Bonnet coupling lies outside the range allowed by conformal collider bounds. It further states that the unstable modes are connected to the boundary causality-violating modes by a phase rotation of complex boundary momentum.

Significance. If the central claim holds, the result would link gravitational stability thresholds directly to causality bounds in higher-curvature AdS gravity, offering a concrete test of consistency conditions for effective theories dual to conformal field theories. The phase-rotation technique for relating quasinormal spectra would be a useful technical tool if shown to preserve the relevant boundary conditions without introducing extraneous modes.

major comments (1)
  1. The equivalence between the conformal collider bound range and the stability threshold, together with the phase-rotation mapping between unstable and causality-violating modes, is the load-bearing claim. The abstract asserts that this mapping holds under the full dynamical analysis, yet no derivation is visible showing that the analytic continuation preserves the quasinormal spectrum, boundary conditions, or absence of singularities for generic wave numbers.

Simulated Author's Rebuttal

1 responses · 0 unresolved

We thank the referee for their careful reading of the manuscript and for highlighting the need for greater clarity on the phase-rotation mapping. We address the major comment below and will revise the manuscript to include an explicit derivation.

read point-by-point responses

  1. Referee: The equivalence between the conformal collider bound range and the stability threshold, together with the phase-rotation mapping between unstable and causality-violating modes, is the load-bearing claim. The abstract asserts that this mapping holds under the full dynamical analysis, yet no derivation is visible showing that the analytic continuation preserves the quasinormal spectrum, boundary conditions, or absence of singularities for generic wave numbers.

    Authors: We agree that the manuscript would benefit from an explicit derivation showing that the phase rotation of complex boundary momentum preserves the quasinormal spectrum, boundary conditions, and absence of singularities. The linearized perturbation equations in five-dimensional Gauss-Bonnet gravity are analytic in the momentum components, so rotating the complex wave-vector parameter maps solutions while preserving the ingoing horizon condition and the normalizable AdS boundary condition. In the revised version we will add a dedicated subsection (or appendix) that derives this mapping explicitly for generic wave numbers and confirms that no extraneous singularities are introduced inside the relevant parameter domain. revision: yes

Circularity Check

0 steps flagged

No significant circularity detected from available text

full rationale

The provided abstract states the main results without any equations, derivations, or explicit citations visible. The claim that black branes are unstable outside the conformal collider bound range, with unstable modes connected to causality-violating modes by phase rotation of complex momentum, is presented as a finding rather than a self-definition or fitted input renamed as prediction. No load-bearing self-citation chains, ansatz smuggling, or uniqueness theorems imported from the authors' prior work are evident in the text. The derivation chain cannot be walked for reductions to inputs because no specific steps, equations, or references appear; the result is therefore treated as self-contained against external benchmarks with no circularity.

Axiom & Free-Parameter Ledger

0 free parameters · 0 axioms · 0 invented entities

No information on free parameters, axioms, or invented entities is available from the abstract.

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discussion (0)

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