Recognition: 2 theorem links
· Lean TheoremOscillon Formation in Palatini Modified Gravity Theories
Pith reviewed 2026-05-12 02:13 UTC · model grok-4.3
The pith
Oscillons form during preheating in Palatini gravity with non-minimal coupling and source ultra-high-frequency gravitational waves.
A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.
Core claim
In the Palatini formulation with non-minimal coupling of the inflaton to the Ricci scalar and a polynomial potential, the field equations admit oscillatory decaying solutions whose power spectra exhibit the growth of perturbations at relevant k modes that is characteristic of oscillon formation. The equation of state derived from the simulation indicates a prolonged period of oscillon domination in the early universe, while the asymmetric spatial distribution of these configurations generates primordial gravitational waves lying in the ultra-high-frequency regime.
What carries the argument
Lattice evolution of the inflaton dynamics under the Palatini action with non-minimal coupling, used to extract power spectra, equation-of-state evolution, and the resulting gravitational-wave spectrum.
If this is right
- Oscillon domination extends over a longer interval than in standard preheating scenarios, altering the expansion history before radiation domination.
- Asymmetric energy distributions from the oscillons source a primordial gravitational-wave background in the ultra-high-frequency range.
- The gravitational-wave spectrum overlaps with the sensitivity windows of several planned high-frequency detectors and experiments.
- The power spectrum of field perturbations grows in a manner consistent with the formation and persistence of oscillons.
Where Pith is reading between the lines
- Oscillon formation appears robust when gravity is reformulated in the Palatini style, suggesting the phenomenon is not limited to the metric formalism.
- Detection of ultra-high-frequency gravitational waves could provide an indirect probe of the non-minimal coupling strength used in the Palatini model.
Load-bearing premise
The chosen polynomial potential and specific non-minimal coupling in the Palatini action produce stable dynamics that the lattice simulation resolves without introducing unaccounted instabilities or artifacts.
What would settle it
A high-resolution lattice run that yields neither oscillatory decaying field profiles nor clear peaks in the perturbation power spectrum at the expected k modes would falsify the formation of oscillons in this setup.
read the original abstract
We investigate the formation of spatially localized, oscillatory in time and non topological solitonic, quasi-stable energy configurations, Oscillons, which are formed at the end of Inflationary epoch, during the preheating phase and decay over long periods of time. Oscillons have been previously studied in literature in the regime of General Relativity using Metric Formalism. In this paper we look for formation of these energy lumps by modifying the gravity part of the Einstein Hilbert Action, considering a non minimal coupling of the scalar field with Ricci Scalar,$R$, and working in an alternative formulation of General Relativity known as Palatini Formalism. The potential we consider is of polynomial form. We demonstrate numerically, using CosmoLattice, that the equation governing the dynamics of the Inflaton scalar field give oscillatory and decaying solutions as it is expected in the case of Oscillons, with power spectrum governing the growth of perturbations of $k$ modes. The equation of state reveals an extended period of Oscillon domination in the early universe. Along with this, the Primordial Gravitational Wave spectrum due to asymmetric distribution of these energy configurations have also been studied. We observe that these generate Ultra-High Frequency regime Gravitational Waves, which lie in the range of the planned future detectors and experiments.
Editorial analysis
A structured set of objections, weighed in public.
Referee Report
Summary. The paper investigates oscillon formation in Palatini modified gravity with a non-minimal coupling of the inflaton to the Ricci scalar and a polynomial potential. Using numerical lattice simulations in CosmoLattice, it reports oscillatory and decaying solutions for the inflaton field, a power spectrum for perturbation growth, an extended period of oscillon domination in the equation of state, and the production of ultra-high-frequency primordial gravitational waves from asymmetric energy distributions.
Significance. If the numerical results hold after validation, the work extends oscillon studies from General Relativity to Palatini gravity, offering a concrete example of how modified gravity affects preheating dynamics and generates potentially observable UHF gravitational waves. The numerical demonstration itself, if properly documented, constitutes a useful addition to the literature on early-universe solitons.
major comments (3)
- [§4] §4 (Numerical Simulations): No lattice resolution, grid size, time-step criteria, or convergence tests are reported for the CosmoLattice runs. Without these, or explicit validation against the GR limit, it is impossible to rule out resolution artifacts in the claimed oscillatory/decaying solutions and k-mode power spectrum.
- [§5] §5 (Gravitational Waves): The ultra-high-frequency GW spectrum is presented as arising from oscillon asymmetry, yet no resolution-dependence study or comparison run with higher lattice density is shown; this directly affects the load-bearing claim that these signals fall in the range of planned detectors.
- [§3.1] §3.1 (Field Equations): The Palatini field equations with the chosen non-minimal coupling and polynomial potential are integrated directly, but no analytic check or limiting-case reduction to known GR oscillon behavior is provided to anchor the numerical results.
minor comments (2)
- [Abstract] The abstract omits the explicit form of the polynomial potential and the value of the non-minimal coupling coefficient; these should be stated for reproducibility.
- [Figures] Figure captions for the power spectra and equation-of-state evolution should include the lattice parameters used in each run.
Simulated Author's Rebuttal
We thank the referee for their careful reading of the manuscript and for the constructive comments, which have helped us identify areas where the presentation of the numerical results can be strengthened. We address each major comment below and have prepared revisions to the manuscript accordingly.
read point-by-point responses
-
Referee: [§4] §4 (Numerical Simulations): No lattice resolution, grid size, time-step criteria, or convergence tests are reported for the CosmoLattice runs. Without these, or explicit validation against the GR limit, it is impossible to rule out resolution artifacts in the claimed oscillatory/decaying solutions and k-mode power spectrum.
Authors: We agree that the numerical implementation details require fuller documentation. In the revised manuscript we will report the specific lattice resolution, grid size, time-step criteria, and Courant factor employed in CosmoLattice. We will also add convergence tests performed at multiple resolutions and an explicit validation run in the GR limit (vanishing non-minimal coupling) that reproduces the known oscillon formation and power-spectrum evolution reported in the literature. revision: yes
-
Referee: [§5] §5 (Gravitational Waves): The ultra-high-frequency GW spectrum is presented as arising from oscillon asymmetry, yet no resolution-dependence study or comparison run with higher lattice density is shown; this directly affects the load-bearing claim that these signals fall in the range of planned detectors.
Authors: We accept that a resolution study is necessary to support the robustness of the GW spectrum. The revised version will include additional simulations at higher lattice densities together with a direct comparison of the resulting GW spectra, demonstrating that the ultra-high-frequency features converge and are not numerical artifacts. revision: yes
-
Referee: [§3.1] §3.1 (Field Equations): The Palatini field equations with the chosen non-minimal coupling and polynomial potential are integrated directly, but no analytic check or limiting-case reduction to known GR oscillon behavior is provided to anchor the numerical results.
Authors: We will add a brief analytic subsection in §3.1 that explicitly reduces the Palatini field equations to the standard GR form in the limit of vanishing non-minimal coupling. This reduction recovers the known GR oscillon equations, thereby anchoring the numerical results to established literature. revision: yes
Circularity Check
No circularity: results are direct outputs of lattice simulation
full rationale
The paper's central results are obtained by numerically integrating the modified field equations in Palatini gravity with a chosen polynomial potential using the CosmoLattice code. The reported oscillatory/decaying solutions, k-mode power spectra, equation-of-state evolution, and induced GW spectrum are simulation outputs, not quantities fitted to target data or defined in terms of themselves. No load-bearing self-citations, ansatzes smuggled via prior work, or uniqueness theorems are invoked to force the conclusions; the derivation chain consists of standard discretization and evolution of the action-derived equations. This is self-contained against external benchmarks and receives the default non-circularity finding.
Axiom & Free-Parameter Ledger
free parameters (2)
- non-minimal coupling coefficient
- polynomial potential coefficients
axioms (2)
- domain assumption The Palatini formalism treats the metric and the affine connection as independent variables.
- domain assumption The inflaton potential is a polynomial function of the scalar field.
Lean theorems connected to this paper
-
IndisputableMonolith/Cost/FunctionalEquation.leanwashburn_uniqueness_aczel unclearWe demonstrate numerically, using CosmoLattice, that the equation governing the dynamics of the Inflaton scalar field give oscillatory and decaying solutions... with power spectrum... equation of state... Primordial Gravitational Wave spectrum
-
IndisputableMonolith/Foundation/RealityFromDistinction.leanreality_from_one_distinction unclearf(R,Φ)=G(Φ)(R+αR²) ... non-canonical quartic kinetic term X²
Reference graph
Works this paper leans on
-
[1]
Guth,Inflationary universe: A possible solution to the horizon and flatness problems, Phys
A.H. Guth,Inflationary universe: A possible solution to the horizon and flatness problems, Phys. Rev. D23(1981) 347
work page 1981
-
[2]
A. Linde,A new inflationary universe scenario: A possible solution of the horizon, flatness, homogeneity, isotropy and primordial monopole problems,Physics Letters B108(1982) 389
work page 1982
-
[3]
Planck 2018 results. X. Constraints on inflation
A. Linde,Chaotic inflation,Physics Letters B129(1983) 177. [4]Planckcollaboration,Planck 2018 results. X. Constraints on inflation,Astron. Astrophys. 641(2020) A10 [1807.06211]
work page internal anchor Pith review Pith/arXiv arXiv 1983
-
[4]
P.A.R. Ade, Z. Ahmed, R.W. Aikin et al.,Improved constraints on cosmology and foregrounds from BICEP2 and Keck Array cosmic microwave background data with inclusion of 95 GHz band,Physical Review Letters116(2016)
work page 2016
-
[5]
P.A.R. Ade, Z. Ahmed, M. Amiri et al.,Improved constraints on primordial gravitational waves using Planck, WMAP, and BICEP/Keck observations through the 2018 observing season,Physical Review Letters127(2021)
work page 2018
-
[6]
B.A. Bassett, S. Tsujikawa and D. Wands,Inflation dynamics and reheating,Rev. Mod. Phys. 78(2006) 537
work page 2006
-
[7]
R. Allahverdi, R. Brandenberger, F.-Y. Cyr-Racine and A. Mazumdar,Reheating in inflationary cosmology: Theory and applications,Annual Review of Nuclear and Particle Science60(2010) 27
work page 2010
-
[8]
D.I. Kaiser,Preheating in an expanding universe: Analytic results for the massless case, Physical Review D56(1997) 706
work page 1997
- [9]
- [10]
-
[11]
D.G. Figueroa, A. Florio, F. Torrenti and W. Valkenburg,The art of simulating the early universe. part i. integration techniques and canonical cases,Journal of Cosmology and Astroparticle Physics2021(2021) 035. – 30 –
work page 2021
-
[12]
The Universal Rotation Curve of Spiral Galaxies: I. the Dark Matter Connection
M. Persic, P. Salucci and F. Stel,The universal rotation curve of spiral galaxies — I. The dark matter connection,Mon. Not. R. Astron. Soc.281(1996) 27 [astro-ph/9506004]
work page Pith review arXiv 1996
-
[13]
B. Famaey and S.S. McGaugh,Modified Newtonian dynamics (MOND): Observational phenomenology and relativistic extensions,Living Reviews in Relativity15(2012)
work page 2012
-
[14]
Kroupa,The Dark Matter Crisis: Falsification of the Current Standard Model of Cosmology,Publ
P. Kroupa,The Dark Matter Crisis: Falsification of the Current Standard Model of Cosmology,Publ. Astron. Soc. Australia29(2012) 395 [1204.2546]
-
[15]
J.S. Bullock and M. Boylan-Kolchin,Small-Scale Challenges to theΛCDM Paradigm,Annual Review of Astronomy and Astrophysics55(2017) 343
work page 2017
-
[16]
E. Di Valentino, O. Mena, S. Pan, L. Visinelli, W. Yang, A. Melchiorri et al.,In the realm of the Hubble tension—a review of solutions,Classical and Quantum Gravity38(2021) 153001
work page 2021
-
[17]
S.M. Carroll, A. De Felice, V. Duvvuri, D.A. Easson, M. Trodden and M.S. Turner, Cosmology of generalized modified gravity models,Physical Review D71(2005)
work page 2005
- [18]
-
[19]
R. Maartens and K. Koyama,Brane-world gravity,Living Reviews in Relativity13(2010)
work page 2010
-
[20]
T. Jacobson and D. Mattingly,Gravity with a dynamical preferred frame,Physical Review D 64(2001)
work page 2001
-
[21]
Wagoner,Scalar-tensor theory and gravitational waves,Phys
R.V. Wagoner,Scalar-tensor theory and gravitational waves,Phys. Rev. D1(1970) 3209
work page 1970
-
[22]
Bergmann,Comments on the scalar-tensor theory,International Journal of Theoretical Physics1(1968) 25
P.G. Bergmann,Comments on the scalar-tensor theory,International Journal of Theoretical Physics1(1968) 25
work page 1968
-
[23]
T.P. Sotiriou and V. Faraoni,f(r)theories of gravity,Reviews of Modern Physics82(2010) 451
work page 2010
-
[24]
A. De Felice and S. Tsujikawa,f(r) theories,Living Reviews in Relativity13(2010)
work page 2010
-
[25]
S. Nojiri and S.D. Odintsov,Unified cosmic history in modified gravity: From f(r) theory to lorentz non-invariant models,Physics Reports505(2011) 59–144
work page 2011
- [26]
-
[27]
Woodard,Avoiding dark energy with 1/r modifications of gravity, (Berlin, Heidelberg), pp
R. Woodard,Avoiding dark energy with 1/r modifications of gravity, (Berlin, Heidelberg), pp. 403–433, Springer Berlin Heidelberg (2007), DOI
work page 2007
- [28]
-
[29]
V.-M. Enckell, K. Enqvist, S. Räsänen and L.-P. Wahlman,Inflation with r2 term in the palatini formulation,Journal of Cosmology and Astroparticle Physics2019(2019) 022
work page 2019
-
[30]
I. Antoniadis, A. Karam, A. Lykkas and K. Tamvakis,Palatini inflation in models with an R2 term,J. Cosmol. Astropart. Phys.2018(2018) 028 [1810.10418]
-
[31]
F. Bauer and D.A. Demir,Inflation with non-minimal coupling: Metric vs. palatini formulations,Physics Letters B665(2008) 222
work page 2008
-
[32]
J. Annala,Higgs inflation and higher-order gravity in Palatini formulation, Master’s thesis, Helsinki U., 2020, [2106.09438]
- [33]
-
[34]
G. Allemandi, A. Borowiec, M. Francaviglia and S.D. Odintsov,Dark energy dominance and cosmic acceleration in first-order formalism,Physical Review D72(2005) . – 31 –
work page 2005
-
[35]
I. Dymnikova, L. Koziel, M. Khlopov and S. Rubin,Quasilumps from first order phase transitions, 2000
work page 2000
-
[36]
Gleiser,Pseudostable bubbles,Physical Review D49(1994) 2978
M. Gleiser,Pseudostable bubbles,Physical Review D49(1994) 2978
work page 1994
-
[37]
A. Kusenko,Solitons in the supersymmetric extensions of the standard model,Physics Letters B405(1997) 108
work page 1997
- [38]
- [39]
-
[40]
Y. Sang and Q.-G. Huang,Oscillons during dirac-born-infeld preheating,Physics Letters B 823(2021) 136781
work page 2021
- [41]
- [42]
-
[43]
J.Y. Widdicombe, T. Helfer and E.A. Lim,Black hole formation in relativistic oscillaton collisions,Journal of Cosmology and Astroparticle Physics2020(2020) 027
work page 2020
- [44]
-
[45]
M.Y. Khlopov, R.V. Konoplich, S.G. Rubin and A.S. Sakharov,First order phase transitions as a source of black holes in the early universe, 1999
work page 1999
- [46]
-
[47]
R. Easther and E.A. Lim,Stochastic gravitational wave production after inflation,Journal of Cosmology and Astroparticle Physics2006(2006) 010
work page 2006
- [48]
-
[49]
S. Antusch, F. Cefalà and S. Orani,Gravitational waves from oscillons after inflation, Physical Review Letters118(2017)
work page 2017
-
[50]
J. Ollé, O. Pujolàs and F. Rompineve,Oscillons and dark matter,Journal of Cosmology and Astroparticle Physics2020(2020) 006
work page 2020
-
[51]
M. Kawasaki, W. Nakano and E. Sonomoto,Oscillon of ultra-light axion-like particle,Journal of Cosmology and Astroparticle Physics2020(2020) 047
work page 2020
-
[52]
Ferreira,Ultra-light dark matter,The Astronomy and Astrophysics Review29(2021)
E.G.M. Ferreira,Ultra-light dark matter,The Astronomy and Astrophysics Review29(2021)
work page 2021
-
[53]
M.A. Amin,Inflaton fragmentation: Emergence of pseudo-stable inflaton lumps (oscillons) after inflation, 2010
work page 2010
-
[54]
M.A. Amin, R. Easther and H. Finkel,Inflaton fragmentation and oscillon formation in three dimensions,Journal of Cosmology and Astroparticle Physics2010(2010) 001
work page 2010
-
[55]
M.A. Amin and D. Shirokoff,Flat-top oscillons in an expanding universe,Physical Review D 81(2010)
work page 2010
- [56]
-
[57]
A. Starobinsky,A new type of isotropic cosmological models without singularity,Physics Letters B91(1980) 99. – 32 –
work page 1980
-
[58]
D.G. Figueroa, A. Florio, F. Torrenti and W. Valkenburg,CosmoLattice: A modern code for lattice simulations of scalar and gauge field dynamics in an expanding universe,Comput. Phys. Commun.283(2023) 108586
work page 2023
- [59]
-
[60]
H.J. Kuralkar, S. Panda and A. Vidyarthi,Observable primordial gravitational waves from non-minimally coupled R2 Palatini modified gravity,JCAP05(2025) 073 [2502.03573]
-
[61]
K. Dimopoulos, A. Karam, S. Sánchez López and E. Tomberg,Palatini r2 quintessential inflation,Journal of Cosmology and Astroparticle Physics2022(2022) 076
work page 2022
-
[62]
B. Leaf,Weyl transformation and the classical limit of quantum mechanics,Journal of Mathematical Physics9(1968) 65
work page 1968
-
[63]
S. Sánchez López, K. Dimopoulos, A. Karam and E. Tomberg,Observable gravitational waves from hyperkination in Palatini gravity and beyond,Eur. Phys. J. C83(2023) 1152 [2305.01399]
-
[64]
N.W. McLachlan,Theory and Application of Mathieu Functions, Oxford University Press Academic Monograph Reprints, Clarendon Press, Oxford (1947)
work page 1947
- [65]
- [66]
-
[67]
G. Felder and I. Tkachev,LATTICEEASY: A program for lattice simulations of scalar fields in an expanding universe,Computer Physics Communications178(2008) 929
work page 2008
-
[68]
A.V. Frolov,DEFROST: a new code for simulating preheating after inflation,Journal of Cosmology and Astroparticle Physics2008(2008) 009
work page 2008
-
[69]
Huang,Art of lattice and gravity waves from preheating,Physical Review D83(2011)
Z. Huang,Art of lattice and gravity waves from preheating,Physical Review D83(2011)
work page 2011
-
[70]
Turner,Coherent scalar-field oscillations in an expanding universe,Phys
M.S. Turner,Coherent scalar-field oscillations in an expanding universe,Phys. Rev. D28 (1983) 1243
work page 1983
- [71]
-
[72]
D. Cormier and R. Holman,Spinodal decomposition and inflation: Dynamics and metric perturbations,Phys. Rev. D62(2000) 023520
work page 2000
-
[73]
Y.L. Launay, G.I. Rigopoulos and E.P.S. Shellard,Bunch-davies initial conditions and non-perturbative inflationary dynamics in numerical relativity, 2025
work page 2025
-
[74]
R. Mahbub and S.S. Mishra,Oscillon formation from preheating in asymmetric inflationary potentials,Physical Review D108(2023)
work page 2023
-
[75]
V. Desjacques, Y.B. Ginat and R. Reischke,Statistics of a single sky: constrained random fields and the imprint of Bardeen potentials on galaxy clustering,Mon. Not. R. Astron. Soc. 504(2021) 5612 [2009.02036]
-
[76]
Rubio,Formation and decay of oscillons in einstein-cartan higgs inflation,2603.19178
J. Rubio,Formation and decay of oscillons in einstein-cartan higgs inflation,2603.19178
-
[77]
M. Piani and J. Rubio,Preheating in einstein-cartan higgs inflation: oscillon formation, Journal of Cosmology and Astroparticle Physics2023(2023) 002
work page 2023
- [78]
-
[79]
K.D. Lozanov, M. Sasaki and J. Tränkle,Constraining the inflaton potential with gravitational waves from oscillons,2601.11360. – 33 –
-
[80]
Y. Sang and Q.-G. Huang,Stochastic gravitational-wave background from axion-monodromy oscillons in string theory during preheating,Physical Review D100(2019)
work page 2019
discussion (0)
Sign in with ORCID, Apple, or X to comment. Anyone can read and Pith papers without signing in.