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REVIEW

Modern tests of Lorentz invariance

General Relativity and Quantum Cosmology · Submitted 22 Feb 2005 · 281 references

Pith's verdict: The canonical 2005 survey of Lorentz-violation phenomenology; its real payload is a hedged naturalness argument in §4.3/§8, and the one soft spot is a 10σ table entry waved off on the authority of a preprint.

T0 · AI review

How this review was made: An AI referee (selfhosted/deepseek-v4.1-flash) read the paper on October 29, 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.

  1. T0 AI review An AI read the paper and answered a fixed list of questions.
  2. T1 Audit Automatic checks that the references and files the paper relies on exist and match.
  3. T2 Compute The paper's code or calculations re-run with the same results.
  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/0502097 (version 2)
Pith ID4NQWEA73, Pith's permanent record of this paper and its review
CitationDavid Mattingly. "Modern tests of Lorentz invariance." arXiv:gr-qc/0502097 (2005). https://pith.science/paper/4NQWEA73
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Referee report
The paper

The paper claims

The evidence now leaves no easy room for Planck-scale Lorentz violation at or below dimension six.

The reading

This review asks whether the last decade of Lorentz-invariance tests has closed the door on Planck-scale violations of relativity. It catalogues the theoretical frameworks—the Standard Model Extension, Robertson–Mansouri–Sexl, doubly special relativity, non-systematic dispersion, and dynamical aether—and maps each class of experiment onto the coefficients those frameworks define. Its central synthesis is that terrestrial clock, cavity, torsion-balance, and Penning-trap measurements now bound the lowest-dimension coefficients so tightly, and astrophysical birefringence and threshold observations reach so far into Planck-suppressed operators, that there is no easy way to embed dimension-six-or-lower Lorentz violation coming solely from Planck-scale physics. The sharpest consequence is that any such violation would need a custodial symmetry, such as supersymmetry combined with CPT, or an extra-dimensional hiding place, to explain why low-energy experiments have not already seen it.

What carries the argument

The load-bearing machinery is the Standard Model Extension (SME), especially its minimal version, which writes every Lorentz-violating coupling as a fixed tensor coefficient multiplying a Standard Model operator. The review uses the SME to translate disparate experiments into common parameters: a clock comparison constrains neutron $b_J$, a cavity resonance constrains photon $κ_{e-}$ and $κ_{o+}$, and a cosmic-ray threshold constrains a dispersion coefficient $f^{(n)}$. For astrophysics it adds the modified dispersion relation $E^2=m^2+p^2+f^{(n)}p^n/E_{Pl}^{n-2}$ and threshold theorems stating that at a reaction threshold the outgoing momenta are parallel and the incoming momenta anti-parallel. The concordant frame—the frame in which all Lorentz-violating coefficients are small—lets the review compare limits without committing to a preferred observer. Alternative frameworks, doubly special relativity and the dynamical aether, are carried along because they evade some of these constraints and predict different signatures.

Extended reading notes

Core claim

The paper's central claim is a synthesis rather than a single measurement: the existing web of constraints leaves no natural, unsuppressed route for Planck-scale Lorentz violation to appear as operators of dimension six or below. The review supports this by collecting terrestrial limits on the minimal Standard Model Extension—components of $c_{μν}$, $b_J$, $κ_{e-}$, and $κ_{o+}$ at levels from roughly $10^{-15}$ to $10^{-27}$ GeV—and astrophysical limits from photon time of flight, birefringence, photon decay, vacuum Cerenkov emission, the GZK cutoff, synchrotron emission, and neutrino oscillations. The astrophysical bounds reach coefficients of order $10^{-14}$ or better for dimension-five and dimension-six dispersion, even though the Planck scale is far above any observed particle energy. The conclusion is that a viable Lorentz-violating extension of known physics must either be protected by supersymmetry and CPT, hidden in an extra dimension, or fine-tuned; otherwise the same radiative corrections that generate low-dimension operators should already have produced a signal.

Load-bearing premise

The synthesis rests on the premise that, without a protective symmetry, radiative corrections will drag Planck-scale Lorentz violation down to dimension-four operators large enough for existing terrestrial experiments to see, so the absence of a low-energy signal is evidence against the whole programme.

Editorial extensions

If this is right

  • If the synthesis is right, quantum-gravity models that break Lorentz invariance at the Planck scale must come with a custodial symmetry or a screening mechanism, or they are already excluded by existing data.
  • The same bounds turn every improved clock, cavity, torsion-balance, and Penning-trap measurement into a sharper probe of Planck-scale physics, even though those experiments operate at laboratory energies.
  • Astrophysical thresholds and birefringence will remain the only practical route to dimension-five and dimension-six operators, but their interpretation depends on assuming reaction dynamics close to the Lorentz-invariant case.
  • Doubly special relativity stays viable precisely because it has no preferred frame and evades threshold constraints; an energy-dependent time of flight without birefringence would be its clean signature.
  • In the gravitational sector, dynamical Lorentz violation predicts extra gravitational-wave polarizations and preferred-frame post-Newtonian parameters, giving a separate channel for tests.

Reading between the lines

Editorial extensions of the paper, not claims the author makes directly.

  • The review's naturalness argument cuts both ways: if no Lorentz violation is found, it says more about which quantum-gravity models are natural than about whether relativity is exact; if a signal appears only astrophysically, the burden shifts to finding a low-energy screening mechanism.
  • The catalogue of bounds is not statistically combined; a joint likelihood over the SME coefficients could close parameter space more sharply than the individual limits quoted here.
  • The concordant-frame assumption may be weakest in the early universe or near compact objects, where a dynamical Lorentz-violating field could vary in space and time and evade terrestrial bounds.
  • A confirmed DSR time-of-flight signal would not just constrain a model; it would show that the effective-field-theory logic underlying most of the review's strongest bounds is the wrong description, making the absence of birefringence a decisive cross-check.
Original abstract

Motivated by ideas about quantum gravity, a tremendous amount of effort over the past decade has gone into testing Lorentz invariance in various regimes. This review summarizes both the theoretical frameworks for tests of Lorentz invariance and experimental advances that have made new high precision tests possible. The current constraints on Lorentz violating effects from both terrestrial experiments and astrophysical observations are presented.

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, 2,888 input tokens, $0.0001 reported.

What the abstract itself states, as probabilities: claims first 0.02 · states limitation 0.06 · human participants 0.04 · controlled comparison 0.03 · randomized assignment 0.01 · states quantitative result 0.05 · compares with prior results 0.13 · mentions code or data availability 0.02.

The abstract, sentence by sentence

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

Motivated by ideas about quantum gravity, a tremendous amount of effort over the past decade has gone into testing Lorentz invariance in various regimes. This review summarizes both the theoretical frameworks for tests of Lorentz invariance and experimental advances that have made new high precision tests possible. The current constraints on Lorentz violating effects from both terrestrial experiments and astrophysical observations are presented.

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 Motivated by ideas about quantum gravity, a tremendous amount of effort over the past decade has gone into testing Lorentz invariance in various regimes. background 1.00 0.04 0.04 asserted 0.99
s1 This review summarizes both the theoretical frameworks for tests of Lorentz invariance and experimental advances that have made new high precision tests possible. contribution 1.00 0.38 0.13 asserted 0.97
s2 The current constraints on Lorentz violating effects from both terrestrial experiments and astrophysical observations are presented. result 0.58 0.28 0.24 asserted 0.92

What kind of paper the classifier reports this is: review 1.00 · evidence from literature 0.97.

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

Figures
Figure 1. Elements involved in threshold constraints.
Figure 2. Total outgoing particle energy in symmetric and as
Figure 3. An example of an upper and lower threshold.
Figure 4. Constraints on LV in QED at n = 3 on a log-log plot. For negative parameters minus the logarithm of the absolute value is plotted, and region of width 10−10 is excised around each axis. The constraints in solid lines apply to ξ and both η±, and are symmetric about both the ξ and the η axis. At least one of the two pairs (η±, ξ) must lie within the union of the dashed bell-shaped region and its reflection about the ξ axis. Intersecting lines are truncated where they cross. 50

Figures reproduced from arXiv:gr-qc/0502097 by the authors.

References
How later papers used it

261 later papers cite it

Evidence: some. 257 of the citing papers share no author with it, and 4 of those carry a confident label from Pith's citation classifier.

Pith read 39 of the 362 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

Cites it as support 1 of 3 papers with this label
How the literature uses it

219 arXiv papers cite this in 315 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 · 172 sentences without a confident label

Compares with it 1 paper
Cites it as support 2 papers
Cites it as background 125 papers

Discussion

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