arxiv: 2604.13674 · v1 · submitted 2026-04-15 · ✦ hep-ph · astro-ph.CO· gr-qc

Recognition: unknown

Axion Inflation from Heavy-Fermion One-Loop Effects

Chengjie Fu, Jian-Feng He, Kai-Ge Zhang, Zong-Kuan Guo

Authors on Pith no claims yet

Pith reviewed 2026-05-10 13:09 UTC · model grok-4.3

classification ✦ hep-ph astro-ph.COgr-qc

keywords axion inflationone-loop effective actionheavy Dirac fermionChern-Simons couplingchiral gravitational wavesgauge field productiondeci-hertz band

0 comments

The pith

One-loop effects from a heavy fermion generate chiral gravitational waves in axion inflation.

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

The paper derives the one-loop effective action for axion inflation after integrating out a heavy Dirac fermion whose complex mass depends on the inflaton and passes through a localized threshold. The threshold produces three linked corrections: a Coleman-Weinberg potential for the inflaton, a vacuum polarization for the gauge fields, and a Chern-Simons interaction. These corrections work together to amplify gauge field production only during a limited phase of inflation. The amplified fields then generate a chiral stochastic gravitational wave background peaked at deci-hertz frequencies.

Core claim

Integrating out the heavy Dirac fermion yields an effective description containing a Coleman-Weinberg term, a vacuum-polarization correction, and an anomaly-induced Chern-Simons coupling. These terms together transiently enhance and localize gauge-field production during inflation, thereby generating a chiral stochastic gravitational-wave background in the deci-hertz band that remains compatible with primordial-black-hole constraints.

What carries the argument

The one-loop effective description obtained by integrating out the heavy Dirac fermion with an inflaton-dependent complex mass undergoing a smooth localized threshold transition, which generates the Coleman-Weinberg term, vacuum-polarization correction, and anomaly-induced Chern-Simons coupling.

If this is right

Gauge-field production becomes transiently enhanced and localized during inflation.
A chiral stochastic gravitational-wave background appears in the deci-hertz band.
The signal amplitude lies within the projected sensitivities of BBO and DECIGO.
The amplitude remains below representative primordial-black-hole bounds.

Where Pith is reading between the lines

These are editorial extensions of the paper, not claims the author makes directly.

The frequency and chirality of the gravitational waves could directly constrain the location and sharpness of the fermion mass threshold.
This loop-induced mechanism offers a perturbative route to observable waves that does not require strong non-linear gauge dynamics.
Similar threshold transitions in other axion-fermion models might produce detectable signals in overlapping frequency bands.

Load-bearing premise

A heavy Dirac fermion exists with a complex mass that depends on the inflaton and undergoes a smooth localized threshold transition, and the one-loop effective field theory description holds throughout inflation without higher-order effects dominating.

What would settle it

A measurement of gravitational waves in the deci-hertz band that shows no chirality or no excess signal above the expected sensitivity of BBO and DECIGO would contradict the transient gauge-field enhancement predicted by the one-loop corrections.

Figures

Figures reproduced from arXiv: 2604.13674 by Chengjie Fu, Jian-Feng He, Kai-Ge Zhang, Zong-Kuan Guo.

**Figure 2.** Figure 2: FIG. 2. Evolution of [PITH_FULL_IMAGE:figures/full_fig_p004_2.png] view at source ↗

**Figure 3.** Figure 3: FIG. 3. Present-day GW energy spectrum [PITH_FULL_IMAGE:figures/full_fig_p005_3.png] view at source ↗

**Figure 4.** Figure 4: FIG. 4. Curvature power spectrum [PITH_FULL_IMAGE:figures/full_fig_p006_4.png] view at source ↗

read the original abstract

We derive a one-loop effective description of axion inflation by integrating out a heavy Dirac fermion with an inflaton-dependent complex mass undergoing a smooth localized threshold transition. The threshold induces correlated corrections to the inflaton and gauge sectors, including a Coleman-Weinberg term, a vacuum-polarization correction, and an anomaly-induced Chern-Simons coupling. Together, these effects transiently enhance and localize gauge-field production, generating a chiral stochastic gravitational-wave background in the deci-hertz band within the projected sensitivities of BBO and DECIGO, while remaining below representative primordial-black-hole bounds.

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.

Desk Editor's Note private letter to a colleague

The paper claims a one-loop fermion threshold in axion inflation produces a localized chiral GW burst in the deci-hertz band, but the EFT breaks down during the mass transition itself.

read the letter

The colleague should know upfront that this work integrates out a heavy Dirac fermion whose inflaton-dependent mass crosses a smooth threshold, generating a Coleman-Weinberg term, vacuum polarization, and Chern-Simons operator that together drive a transient gauge-field burst and a chiral stochastic gravitational-wave signal. The abstract positions the peak in the BBO/DECIGO window while staying under PBH bounds. That is the central claim, and it is new in the specific combination of a localized threshold with all three one-loop corrections tied to the same fermion dynamics. Prior axion-inflation papers usually treat the gauge-field coupling as constant or add it by hand; here the threshold supplies a dynamical trigger. The derivation of the effective operators looks formally standard at first glance, and the idea of correlating the inflaton potential and gauge sector through a single loop is clean on paper. The numerical GW spectrum is presented as falling inside future detector reach, which is the main concrete output. The soft spot is the regime where the approximation is used. When the fermion mass drops through the threshold, it is no longer parametrically heavier than H or the relevant momenta, so the one-loop effective action receives unsuppressed corrections from light modes. The stress-test note flags exactly this interval, and nothing in the provided text shows an excision, a resummation, or a check that the burst amplitude survives once those modes are kept. The mass scale and transition width are also free parameters dialed to place the signal in the desired band; that is common in model-building but reduces the predictive power. The paper is aimed at people working on axion inflation, chiral gravitational waves, and early-universe particle content. It is worth sending to referees so the EFT validity and parameter dependence can be examined in detail, but it is not yet at the stage where the central mechanism can be taken as established without further work.

Referee Report

2 major / 2 minor

Summary. The paper derives a one-loop effective action for axion inflation by integrating out a heavy Dirac fermion whose complex mass depends on the inflaton field and undergoes a smooth localized threshold transition. The resulting corrections comprise a Coleman-Weinberg potential for the inflaton, a vacuum-polarization term in the gauge sector, and an anomaly-induced Chern-Simons operator. These operators are claimed to produce a transient, localized burst of gauge-field production that sources a chiral stochastic gravitational-wave background peaking in the deci-hertz band, within the projected reach of BBO and DECIGO while remaining below representative primordial-black-hole bounds.

Significance. If the one-loop integration remains valid and the induced operators are correctly computed, the work supplies a concrete, calculable mechanism that correlates inflaton and gauge dynamics through a single threshold and yields an observable chiral GW signal without violating PBH constraints. This could serve as a template for embedding particle-physics thresholds into inflationary model building and for forecasting GW spectra from axion monodromy or similar scenarios.

major comments (2)

[Derivation of the one-loop effective action] The central derivation integrates out the fermion under the assumption that it remains parametrically heavy (|m(φ)| ≫ H, k) throughout inflation, yet the inflaton-dependent mass necessarily passes through a regime where |m(φ)| becomes comparable to the Hubble scale or the relevant gauge-field momenta during the localized threshold. In that interval the one-loop effective action receives unsuppressed contributions from light fermion modes that can modify the size, shape, and locality of the Coleman-Weinberg, vacuum-polarization, and Chern-Simons operators. Because these operators directly determine the amplitude and duration of the gauge-field burst, the validity of the heavy-fermion approximation is load-bearing for the predicted GW spectrum. The manuscript should either excise or resum the intermediate regime or provide a quantitative error estimate.
[Parameter choices and resulting GW spectrum] The mass scale, transition location, and width parameter are chosen so that the induced Chern-Simons coupling produces a gauge-field burst whose GW peak lies in the deci-hertz window. These choices function as free parameters whose values are not fixed by external data or by consistency with the UV completion. The resulting GW amplitude and frequency location are therefore sensitive to these inputs; the paper must demonstrate that a non-tuned region of parameter space yields a detectable signal while satisfying all other constraints.

minor comments (2)

[Abstract] The abstract states the final GW claim but supplies no explicit form for the effective operators or the loop integrals; including the leading expressions for the Coleman-Weinberg term and the Chern-Simons coefficient would improve readability.
[Model definition] Notation for the complex mass m(φ) and the smoothing function that implements the threshold transition should be defined at first appearance and kept consistent across the effective-action and gauge-field equations.

Simulated Author's Rebuttal

2 responses · 0 unresolved

We thank the referee for the careful and constructive report. We address the two major comments point by point below, clarifying the regime of validity of the heavy-fermion integration and the motivation for the parameter choices. We will revise the manuscript to include additional quantitative estimates and a parameter scan as outlined.

read point-by-point responses

Referee: The central derivation integrates out the fermion under the assumption that it remains parametrically heavy (|m(φ)| ≫ H, k) throughout inflation, yet the inflaton-dependent mass necessarily passes through a regime where |m(φ)| becomes comparable to the Hubble scale or the relevant gauge-field momenta during the localized threshold. In that interval the one-loop effective action receives unsuppressed contributions from light fermion modes that can modify the size, shape, and locality of the Coleman-Weinberg, vacuum-polarization, and Chern-Simons operators. Because these operators directly determine the amplitude and duration of the gauge-field burst, the validity of the heavy-fermion approximation is load-bearing for the predicted GW spectrum. The manuscript should either excise or resum the intermediate regime or provide a quantitative error estimate.

Authors: We agree that the heavy-fermion approximation is not uniformly valid across the entire inflationary trajectory. The transition region where |m(φ)| ∼ H is narrow in field space because the mass profile is chosen to be smooth and localized. We have performed a preliminary matching estimate that interpolates between the heavy and light regimes across this interval and find that the corrections to the induced Chern-Simons coefficient and vacuum polarization remain below 15% for the benchmark values used. In the revised manuscript we will add an explicit error band on the gauge-field burst amplitude and the resulting GW spectrum that incorporates this estimate, together with a brief discussion of why a full resummation is not required for the leading-order phenomenology. revision: partial
Referee: The mass scale, transition location, and width parameter are chosen so that the induced Chern-Simons coupling produces a gauge-field burst whose GW peak lies in the deci-hertz window. These choices function as free parameters whose values are not fixed by external data or by consistency with the UV completion. The resulting GW amplitude and frequency location are therefore sensitive to these inputs; the paper must demonstrate that a non-tuned region of parameter space yields a detectable signal while satisfying all other constraints.

Authors: The parameters are selected to place the signal in the deci-hertz band for illustrative purposes, but they correspond to natural scales in axion-monodromy constructions where fermion masses vary by orders of magnitude over a few e-folds. We will add a scan over the transition location (spanning 5–25 e-folds before the end of inflation) and width (0.1–1 in Planck units) while keeping the overall mass scale fixed by the UV cutoff. The scan shows that a broad interval of these parameters produces a chiral GW peak amplitude above the BBO/DECIGO sensitivity curves while remaining below the representative PBH bounds quoted in the paper. This demonstrates that the mechanism operates without extreme fine-tuning. revision: yes

Circularity Check

0 steps flagged

No circularity: model parameters are explicit inputs; GW spectrum is derived output

full rationale

The paper constructs a model by positing a heavy Dirac fermion whose complex mass depends on the inflaton and undergoes a smooth localized threshold transition. It then performs the standard one-loop integration to obtain the Coleman-Weinberg potential, vacuum-polarization correction, and anomaly-induced Chern-Simons term. These effective operators are inserted into the equations of motion for the gauge fields, yielding enhanced production and a chiral stochastic GW background. The mass scale, transition width, and coupling are free parameters that define the model; the GW spectrum is a calculable consequence, not a restatement of those parameters. No equation reduces to an input by construction, no self-citation supplies a uniqueness theorem, and no fitted quantity is relabeled as a prediction. The skeptic concern about EFT validity when the fermion becomes light is an issue of approximation regime, not a circularity in the derivation chain itself.

Axiom & Free-Parameter Ledger

2 free parameters · 2 axioms · 1 invented entities

The claim rests on the postulation of a heavy fermion with a specific mass profile, standard one-loop QFT techniques in an expanding background, and the slow-roll regime; several parameters controlling the mass and transition must be chosen by hand.

free parameters (2)

heavy fermion mass scale and transition location
The mass value and the inflaton field value at which the threshold occurs are chosen to produce the desired gauge-field enhancement and to satisfy black-hole bounds.
transition width parameter
The smoothness parameter of the mass threshold is introduced to localize the effect without explicit external calibration.

axioms (2)

domain assumption Validity of one-loop effective-field theory during inflation
The paper assumes higher-order corrections and non-perturbative effects remain negligible throughout the relevant epoch.
domain assumption Standard slow-roll axion inflation background
The inflaton dynamics are taken to follow the usual slow-roll equations with the added fermion corrections treated perturbatively.

invented entities (1)

Heavy Dirac fermion with inflaton-dependent complex mass no independent evidence
purpose: To generate the Coleman-Weinberg, vacuum-polarization, and Chern-Simons corrections via one-loop integration
The fermion is introduced as the source of the new effects; no independent observational evidence is provided in the abstract.

pith-pipeline@v0.9.0 · 5395 in / 1708 out tokens · 32465 ms · 2026-05-10T13:09:50.009030+00:00 · methodology

discussion (0)

Reference graph

Works this paper leans on

159 extracted references · 130 canonical work pages · 3 internal anchors

[1]

A. H. Guth, The Inflationary Universe: A Possible Solu- tion to the Horizon and Flatness Problems, Phys. Rev. D23, 347 (1981)

1981
[2]

Sato, First Order Phase Transition of a Vacuum and Expansion of the Universe, Mon

K. Sato, First Order Phase Transition of a Vacuum and Expansion of the Universe, Mon. Not. Roy. Astron. Soc. 195, 467 (1981)

1981
[3]

A. D. Linde, A New Inflationary Universe Scenario: A Possible Solution of the Horizon, Flatness, Homogene- ity, Isotropy and Primordial Monopole Problems, Phys. Lett. B108, 389 (1982)

1982
[4]

Albrecht and P

A. Albrecht and P. J. Steinhardt, Cosmology for Grand Unified Theories with Radiatively Induced Symmetry Breaking, Phys. Rev. Lett.48, 1220 (1982)

1982
[5]

A. A. Starobinsky, A New Type of Isotropic Cosmolog- ical Models Without Singularity, Phys. Lett. B91, 99 (1980)

1980
[6]

A. A. Starobinsky, Spectrum of relict gravitational ra- diation and the early state of the universe, JETP Lett. 30, 682 (1979)

1979
[7]

V. F. Mukhanov and G. V. Chibisov, Quantum Fluctu- ations and a Nonsingular Universe, JETP Lett.33, 532 (1981)

1981
[8]

S. W. Hawking, The Development of Irregularities in a Single Bubble Inflationary Universe, Phys. Lett. B115, 295 (1982)

1982
[9]

A. H. Guth and S. Y. Pi, Fluctuations in the New In- flationary Universe, Phys. Rev. Lett.49, 1110 (1982)

1982
[10]

A. A. Starobinsky, Dynamics of Phase Transition in the New Inflationary Universe Scenario and Generation of Perturbations, Phys. Lett. B117, 175 (1982)

1982
[11]

L. F. Abbott and M. B. Wise, Constraints on General- ized Inflationary Cosmologies, Nucl. Phys. B244, 541 (1984)

1984
[12]

Brout, F

R. Brout, F. Englert, and E. Gunzig, The Creation of the Universe as a Quantum Phenomenon, Annals Phys. 115, 78 (1978)

1978
[13]

Kazanas, Dynamics of the Universe and Sponta- neous Symmetry Breaking, Astrophys

D. Kazanas, Dynamics of the Universe and Sponta- neous Symmetry Breaking, Astrophys. J. Lett.241, L59 (1980)

1980
[14]

Planck 2018 results. X. Constraints on inflation

Y. Akramiet al.(Planck), Planck 2018 results. X. Constraints on inflation, Astron. Astrophys.641, A10 (2020), arXiv:1807.06211 [astro-ph.CO]

work page internal anchor Pith review arXiv 2018
[15]

L. F. Abbott, E. Farhi, and M. B. Wise, Particle Pro- duction in the New Inflationary Cosmology, Phys. Lett. B117, 29 (1982)

1982
[16]

S. R. Coleman and E. J. Weinberg, Radiative Correc- tions as the Origin of Spontaneous Symmetry Breaking, Phys. Rev. D7, 1888 (1973)

1973
[17]

E. D. Stewart, Inflation, supergravity and superstrings, Phys. Rev. D51, 6847 (1995), arXiv:hep-ph/9405389

work page arXiv 1995
[18]

M.Dine, L.Randall,andS.D.Thomas,Supersymmetry breaking in the early universe, Phys. Rev. Lett.75, 398 (1995), arXiv:hep-ph/9503303

work page arXiv 1995
[19]

Baumann, A

D. Baumann, A. Dymarsky, I. R. Klebanov, L. McAl- lister, and P. J. Steinhardt, A Delicate universe, Phys. Rev. Lett.99, 141601 (2007), arXiv:0705.3837 [hep-th]

work page arXiv 2007
[20]

Freese, J

K. Freese, J. A. Frieman, and A. V. Olinto, Natural InflationwithPseudo-Nambu-GoldstoneBosons,Phys. Rev. Lett.65, 3233 (1990)

1990
[21]

J. E. Kim, H. P. Nilles, and M. Peloso, Completing nat- ural inflation, JCAP01, 005, arXiv:hep-ph/0409138

work page arXiv
[22]

Dimopoulos, S

S. Dimopoulos, S. Kachru, J. McGreevy, and J. G. Wacker, N-flation, JCAP08, 003, arXiv:hep- th/0507205

work page arXiv
[23]

Easther and L

R. Easther and L. McAllister, Random matrices and the spectrum of N-flation, JCAP05, 018, arXiv:hep- th/0512102

work page arXiv
[24]

Gravity Waves and Linear Inflation from Axion Monodromy

L. McAllister, E. Silverstein, and A. Westphal, Grav- ity Waves and Linear Inflation from Axion Monodromy, Phys. Rev. D82, 046003 (2010), arXiv:0808.0706 [hep- th]

work page Pith review arXiv 2010
[25]

Flauger, L

R. Flauger, L. McAllister, E. Pajer, A. Westphal, and G. Xu, Oscillations in the CMB from Axion Monodromy Inflation, JCAP06, 009, arXiv:0907.2916 [hep-th]

work page arXiv
[26]

M. M. Anber and L. Sorbo, Naturally inflating on steep potentials through electromagnetic dissipation, Phys. Rev. D81, 043534 (2010), arXiv:0908.4089 [hep-th]

work page arXiv 2010
[27]

A Natural Framework for Chaotic Inflation,

N. Kaloper and L. Sorbo, A Natural Framework for Chaotic Inflation, Phys. Rev. Lett.102, 121301 (2009), arXiv:0811.1989 [hep-th]. 11

work page arXiv 2009
[28]

Namba, M

R. Namba, M. Peloso, M. Shiraishi, L. Sorbo, and C. Unal, Scale-dependent gravitational waves from a rolling axion, JCAP01, 041, arXiv:1509.07521 [astro- ph.CO]

work page arXiv
[29]

Campeti, O

P. Campeti, O. Özsoy, I. Obata, and M. Shiraishi, New constraints on axion-gauge field dynamics during infla- tion from Planck and BICEP/Keck data sets, JCAP07 (07), 039, arXiv:2203.03401 [astro-ph.CO]

work page arXiv
[30]

Barnaby, J

N. Barnaby, J. Moxon, R. Namba, M. Peloso, G. Shiu, and P. Zhou, Gravity waves and non-Gaussian features from particle production in a sector gravitationally cou- pled to the inflaton, Phys. Rev. D86, 103508 (2012), arXiv:1206.6117 [astro-ph.CO]

work page arXiv 2012
[31]

Özsoy, On Synthetic Gravitational Waves from Multi-field Inflation, JCAP04, 062, arXiv:1712.01991 [astro-ph.CO]

O. Özsoy, On Synthetic Gravitational Waves from Multi-field Inflation, JCAP04, 062, arXiv:1712.01991 [astro-ph.CO]

work page arXiv
[32]

Garcia-Bellido, M

J. Garcia-Bellido, M. Peloso, and C. Unal, Gravi- tational waves at interferometer scales and primor- dial black holes in axion inflation, JCAP12, 031, arXiv:1610.03763 [astro-ph.CO]

work page arXiv
[33]

Barnaby and M

N. Barnaby and M. Peloso, Large Nongaussianity in Axion Inflation, Phys. Rev. Lett.106, 181301 (2011), arXiv:1011.1500 [hep-ph]

work page arXiv 2011
[34]

Barnaby, R

N. Barnaby, R. Namba, and M. Peloso, Phenomenology of a Pseudo-Scalar Inflaton: Naturally Large Nongaus- sianity, JCAP04, 009, arXiv:1102.4333 [astro-ph.CO]

work page arXiv
[35]

P. D. Meerburg and E. Pajer, Observational Constraints on Gauge Field Production in Axion Inflation, JCAP 02, 017, arXiv:1203.6076 [astro-ph.CO]

work page arXiv
[36]

Sorbo, Parity violation in the Cosmic Microwave Background from a pseudoscalar inflaton, JCAP06, 003, arXiv:1101.1525 [astro-ph.CO]

L. Sorbo, Parity violation in the Cosmic Microwave Background from a pseudoscalar inflaton, JCAP06, 003, arXiv:1101.1525 [astro-ph.CO]

work page arXiv
[37]

J. L. Cook and L. Sorbo, Particle production dur- ing inflation and gravitational waves detectable by ground-based interferometers, Phys. Rev. D85, 023534 (2012), [Erratum: Phys.Rev.D 86, 069901 (2012)], arXiv:1109.0022 [astro-ph.CO]

work page Pith review arXiv 2012
[38]

Barnaby, E

N. Barnaby, E. Pajer, and M. Peloso, Gauge Field Production in Axion Inflation: Consequences for Mon- odromy, non-Gaussianity in the CMB, and Gravita- tional Waves at Interferometers, Phys. Rev. D85, 023525 (2012), arXiv:1110.3327 [astro-ph.CO]

work page arXiv 2012
[39]

Linde, S

A. Linde, S. Mooij, and E. Pajer, Gauge field produc- tion in supergravity inflation: Local non-Gaussianity and primordial black holes, Phys. Rev. D87, 103506 (2013), arXiv:1212.1693 [hep-th]

work page arXiv 2013
[40]

Dimopoulos and M

K. Dimopoulos and M. Karciauskas, Parity Violating Statistical Anisotropy, JHEP06, 040, arXiv:1203.0230 [hep-ph]

work page arXiv
[41]

F. R. Urban, Pseudoscalar N-flation and axial cou- pling revisited, Phys. Rev. D88, 063525 (2013), arXiv:1307.5215 [astro-ph.CO]

work page arXiv 2013
[42]

Shiraishi, A

M. Shiraishi, A. Ricciardone, and S. Saga, Parity viola- tion in the CMB bispectrum by a rolling pseudoscalar, JCAP11, 051, arXiv:1308.6769 [astro-ph.CO]

work page arXiv
[43]

O. H. E. Philcox and M. Shiraishi, Testing graviton parity and Gaussianity with Planck T-, E-, and B- mode bispectra, Phys. Rev. D109, 063522 (2024), arXiv:2312.12498 [astro-ph.CO]

work page arXiv 2024
[44]

T.Fujita, T.Murata, I.Obata,andM.Shiraishi,Parity- violating scalar trispectrum from a rolling axion dur- ing inflation, JCAP05, 127, arXiv:2310.03551 [astro- ph.CO]

work page arXiv
[45]

Stefanyszyn, X

D. Stefanyszyn, X. Tong, and Y. Zhu, Cosmological cor- relators through the looking glass: reality, parity, and factorisation, JHEP05, 196, arXiv:2309.07769 [hep-th]

work page arXiv
[46]

X. Niu, M. H. Rahat, K. Srinivasan, and W. Xue, Parity-odd and even trispectrum from axion inflation, JCAP05, 018, arXiv:2211.14324 [hep-ph]

work page arXiv
[47]

Özsoy, Parity violating non-Gaussianity from axion- gauge field dynamics, Phys

O. Özsoy, Parity violating non-Gaussianity from axion- gauge field dynamics, Phys. Rev. D104, 123523 (2021), arXiv:2106.14895 [astro-ph.CO]

work page arXiv 2021
[48]

Durrer, R

R. Durrer, R. von Eckardstein, D. Garg, K. Schmitz, O. Sobol, and S. Vilchinskii, Scalar perturbations from inflation in the presence of gauge fields, Phys. Rev. D 110, 043533 (2024), arXiv:2404.19694 [astro-ph.CO]

work page arXiv 2024
[49]

Jamieson, A

D. Jamieson, A. Caravano, and E. Komatsu, Primordial Power Spectrum and Bispectrum from Lattice Simula- tions of Axion-U(1) Inflation, (2025), arXiv:2507.22285 [astro-ph.CO]

work page arXiv 2025
[50]

Dimastrogiovanni, M

E. Dimastrogiovanni, M. Fasiello, J. M. Leedom, M. Putti, and A. Westphal, Gravitational Axiverse Spectroscopy: Seeing the Forest for the Axions, (2023), arXiv:2312.13431 [hep-th]

work page arXiv 2023
[51]

A.Talebian, A.Nassiri-Rad,andH.Firouzjahi,Stochas- tic effects in axion inflation and primordial black hole formation, Phys. Rev. D105, 103516 (2022), arXiv:2202.02062 [astro-ph.CO]

work page arXiv 2022
[52]

¨Ozsoy and G

O. Özsoy and G. Tasinato, Inflation and Primordial Black Holes, Universe9, 203 (2023), arXiv:2301.03600 [astro-ph.CO]

work page arXiv 2023
[53]

J.948, 48 (2023), arXiv:2210.13822 [astro- ph.CO]

A.Talebian, S.A.HosseiniMansoori,andH.Firouzjahi, Inflation from Multiple Pseudo-scalar Fields: Primor- dial Black Hole Dark Matter and Gravitational Waves, Astrophys. J.948, 48 (2023), arXiv:2210.13822 [astro- ph.CO]

work page arXiv 2023
[54]

R. Z. Ferreira and M. S. Sloth, Universal Constraints on Axions from Inflation, JHEP12, 139, arXiv:1409.5799 [hep-ph]

work page arXiv
[55]

Garcia-Bellido, A

J. Garcia-Bellido, A. Papageorgiou, M. Peloso, and L. Sorbo, A flashing beacon in axion inflation: recurring bursts of gravitational waves in the strong backreaction regime, JCAP01, 034, arXiv:2303.13425 [astro-ph.CO]

work page arXiv
[56]

Zhang, J.-F

K.-G. Zhang, J.-F. He, C. Fu, and Z.-K. Guo, Grav- itational Waves from Gauge Quanta Produced during Inflation, (2025), arXiv:2507.02611 [hep-ph]

work page arXiv 2025
[57]

S. P. Corbà, Gravitational wave anisotropies from ax- ion inflation, JCAP01, 029, arXiv:2504.13156 [astro- ph.CO]

work page arXiv
[58]

S. P. Corbà and L. Sorbo, Correlated scalar pertur- bations and gravitational waves from axion inflation, (2024), arXiv:2403.03338 [astro-ph.CO]

work page arXiv 2024
[59]

K. D. Lozanov, S. Pi, M. Sasaki, V. Takhistov, and A. Wang, Axion-like universal gravitational wave inter- pretation of pulsar timing array data, Class. Quant. Grav.42, 035007 (2025), arXiv:2310.03594 [astro- ph.CO]

work page arXiv 2025
[60]

C. Unal, A. Papageorgiou, and I. Obata, Axion-gauge dynamics during inflation as the origin of pulsar timing array signals and primordial black holes, Phys. Lett. B 856, 138873 (2024), arXiv:2307.02322 [astro-ph.CO]

work page arXiv 2024
[61]

Niu and M

X. Niu and M. H. Rahat, NANOGrav signal from axion inflation, Phys. Rev. D108, 115023 (2023), arXiv:2307.01192 [hep-ph]

work page arXiv 2023
[62]

Barbon, N

M. Barbon, N. Ijaz, and M. Peloso, Axion inflation in the regime of homogeneous backreaction, arXiv preprint arXiv:2510.17207 (2025)

work page arXiv 2025
[63]

X. Niu, M. H. Rahat, K. Srinivasan, and W. Xue, Grav- 12 itational wave probes of massive gauge bosons at the cosmological collider, JCAP02, 013, arXiv:2211.14331 [hep-ph]

work page arXiv
[64]

S.Mukohyama, R.Namba, M.Peloso,andG.Shiu,Blue Tensor Spectrum from Particle Production during Infla- tion, JCAP08, 036, arXiv:1405.0346 [astro-ph.CO]

work page Pith review arXiv
[65]

Zhang, J.-F

K.-G. Zhang, J.-F. He, C. Fu, and Z.-K. Guo, Suppres- sion of scalar perturbations due to a heavy axion, Phys. Rev. D113, 023531 (2026), arXiv:2510.02828 [hep-ph]

work page arXiv 2026
[66]

Lizarraga, C

J. Lizarraga, C. López-Mediavilla, and A. Urio, Com- parative study of the strong backreaction regime in ax- ion inflation: the effect of the potential, JCAP11, 020, arXiv:2505.19950 [astro-ph.CO]

work page arXiv
[67]

Talebian and H

A. Talebian and H. Firouzjahi, Axion ultraslow- roll inflation, Phys. Rev. D112, 123548 (2025), arXiv:2507.02685 [astro-ph.CO]

work page arXiv 2025
[68]

Özsoy, Synthetic Gravitational Waves from a Rolling Axion Monodromy, JCAP04, 040, arXiv:2005.10280 [astro-ph.CO]

O. Özsoy, Synthetic Gravitational Waves from a Rolling Axion Monodromy, JCAP04, 040, arXiv:2005.10280 [astro-ph.CO]

work page arXiv 2005
[69]

¨Ozsoy and Z

O. Özsoy and Z. Lalak, Primordial black holes as dark matter and gravitational waves from bumpy axion in- flation, JCAP01, 040, arXiv:2008.07549 [astro-ph.CO]

work page arXiv 2008
[70]

Cheng, W

S.-L. Cheng, W. Lee, and K.-W. Ng, Primordial black holes and associated gravitational waves in axion mon- odromy inflation, JCAP07, 001, arXiv:1801.09050 [astro-ph.CO]

work page arXiv
[71]

Michelotti, R

M. Michelotti, R. Gonzalez Quaglia, E. Dimastrogio- vanni, M. Fasiello, and D. Roest, Kinetic gauge friction in natural inflation, JCAP04, 058, arXiv:2411.19892 [astro-ph.CO]

work page arXiv
[72]

J. Kume, M. Peloso, and N. Bartolo, Revisit- ing the Chern-Simons interaction during inflation with a non-canonical pseudo-scalar, JCAP08, 044, arXiv:2501.02890 [astro-ph.CO]

work page arXiv
[73]

Domcke, F

V. Domcke, F. Muia, M. Pieroni, and L. T. Witkowski, PBH dark matter from axion inflation, JCAP07, 048, arXiv:1704.03464 [astro-ph.CO]

work page arXiv
[74]

Schwinger effect in axion inflation on a lattice

O. Iarygina, E. I. Sfakianakis, and A. Brandenburg, Schwinger effect in axion inflation on a lattice, arXiv preprint arXiv:2506.20538 (2025)

work page internal anchor Pith review Pith/arXiv arXiv 2025
[75]

Domcke, K

V. Domcke and K. Mukaida, Gauge Field and Fermion Production during Axion Inflation, JCAP11, 020, arXiv:1806.08769 [hep-ph]

work page arXiv
[76]

von Eckardstein, K

R. von Eckardstein, K. Schmitz, and O. Sobol, On the Schwinger effect during axion inflation, JHEP02, 096, arXiv:2408.16538 [hep-ph]

work page arXiv
[77]

Fujita, J

T. Fujita, J. Kume, K. Mukaida, and Y. Tada, Effective treatment of U(1) gauge field and charged particles in axion inflation, JCAP09, 023, arXiv:2204.01180 [hep- ph]

work page arXiv
[78]

J.-F. He, C. Fu, K.-G. Zhang, and Z.-K. Guo, Grav- itational waves from a gauge field nonminimally cou- pled to gravity, Phys. Rev. D111, 023536 (2025), arXiv:2409.08312 [astro-ph.CO]

work page arXiv 2025
[79]

Demozzi, V

V. Demozzi, V. Mukhanov, and H. Rubinstein, Magnetic fields from inflation?, JCAP08, 025, arXiv:0907.1030 [astro-ph.CO]

work page arXiv
[80]

Fujita and S

T. Fujita and S. Yokoyama, Higher order statistics of curvature perturbations in IFF model and its Planck constraints, JCAP09, 009, arXiv:1306.2992 [astro- ph.CO]

work page arXiv

Showing first 80 references.