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REVIEW 2 major objections 5 minor 45 references

The paper argues that oscillating vector bosons cannot supply dark matter because non-Gaussianity and isocurvature constraints exclude every value of the mixing parameter.

Reviewed by Pith at T0; open to challenge. T0 means a machine referee read the full paper against a public rubric. the ladder, T0–T4 →

T0 review · deepseek-v4-flash

2026-08-04 04:16 UTC pith:J4RLC3BI

load-bearing objection A plausible no-go for isotropized multi-vector DM misalignment, but the strong-mixing leg has a real arithmetic slip and relies on imported formulas that need independent checking before the conclusion is firm. the 2 major comments →

arxiv 2607.14267 v2 pith:J4RLC3BI submitted 2026-07-15 astro-ph.CO gr-qc

Misalignment production of isotropized vector dark matter?

classification astro-ph.CO gr-qc
keywords dark mattervector bosonsmisalignment mechanismkinetic couplinginflationnon-Gaussianityisocurvature fluctuationscosmological perturbations
verification ladder T0 review T1 audit T2 compute T3 formal T4 reserved

The pith

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

Dark matter might be made of vector bosons produced during inflation by the misalignment mechanism, with a kinetic coupling f²F²; to evade anisotropy bounds, the vector condensate is taken to be isotropic. The paper shows that a single mixing parameter h controls how strongly the vector fluctuations source the curvature and entropy perturbations. In the weak-mixing regime, the observed small non-Gaussianity forces h < 3×10⁻⁴, while the CMB bound on isocurvature forces h > 5.2×10⁻³. In the strong-mixing regime, local non-Gaussianity forces h < 9.2, while isocurvature forces h > 45. Because the two constraints cannot be satisfied simultaneously, the mechanism cannot produce all of the dark matter.

Core claim

The central claim is that the isotropized multi-vector misalignment mechanism with kinetic coupling is phenomenologically excluded: the same parameter h that regulates the curvature bispectrum also regulates the entropy power spectrum, and the bounds point in opposite directions. The author presents the incompatibility for h≪1 and h≫1 separately, along with the resulting dead parameter space for the vector-boson mass and the inflationary Hubble scale. The only loophole the author identifies is a vector curvaton, in which case only a fraction of the vector fields would be the dark matter.

What carries the argument

The mixing parameter h, defined as the square root of the ratio of vector-field kinetic energy to inflaton kinetic energy, is the central object. It determines the size of the coupling between inflaton and vector perturbations in the quadratic action. All observational quantities—the curvature power spectrum (e.g., P_R ∝ e^{2.37h} in the strong-mixing regime), the local bispectrum amplitude f_NL^{local}=512 h² N³, and the entropy power spectrum—are expressed in terms of h, which is why the two-sided constraints conflict.

Load-bearing premise

The no-go assumes the perturbation spectra imported from the author's earlier papers—especially the exponential strong-mixing power spectrum and the entropy spectrum—are correct; if those prior calculations are wrong, the contradiction may disappear.

What would settle it

Derive the strong-mixing entropy power spectrum directly from Eq. (48). If the correct scaling is P_S ~ const/h⁴ P_R rather than 2/h² P_R, the isocurvature bound becomes h ≳ 10 instead of h > 45, which would be compatible with the non-Gaussianity bound h < 9.2 and would overturn the no-go. More generally, a first-principles computation of the curvature and entropy spectra in the strong-mixing regime would settle the claim.

Watch this falsifier. Get emailed when new claim-graph text bears on it.

If this is right

  • If the paper is right, the isotropic kinetic-coupling misalignment channel for vector dark matter is closed, regardless of the choice of h.
  • The strong-mixing regime, which would have produced exponentially amplified curvature fluctuations and allowed extremely light vector dark matter, is also excluded.
  • The only open direction proposed is a vector curvaton, where the vector contribution to curvature perturbations is decoupled from the dark-matter abundance.
  • In the Γ_ϕ < m_A case (oscillation after reheating), the strong-mixing regime is additionally excluded by the required inflationary scale H_inf < 10⁻¹⁹ M_pl.

Where Pith is reading between the lines

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

  • The contradiction is structurally robust: any mechanism in which a single mixing parameter controls both curvature and entropy perturbations will face the same squeeze; the specific numbers may change but the no-go shape likely persists.
  • If the strong-mixing entropy spectrum is corrected from P_S ∝ h⁻² to h⁻⁴, the isocurvature bound weakens enough to become marginally compatible with the non-Gaussianity bound, which would reopen part of the parameter space; this is an inference based on the algebra in the paper, not a claim the author makes.
  • The paper's reliance on imported perturbation spectra means a full first-principles derivation of P_R, P_S, and f_NL in the strong-mixing regime would be the decisive check; until then the no-go should be treated as provisional.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit.

Referee Report

2 major / 5 minor

Summary. The paper considers an isotropized multi-vector field with kinetic coupling f^2 F^2 during inflation and asks whether misalignment production can explain dark matter. It derives the background attractor solution and the relic-abundance formulas for the two reheating hierarchies (Gamma_phi > m_A and Gamma_phi < m_A), then imports perturbation calculations from the author's earlier papers to impose constraints from the curvature power spectrum, non-Gaussianities, and isocurvature perturbations. The headline result is a no-go: in both the weak-mixing (h<<1) and strong-mixing (h>>1) regimes, non-Gaussianity and isocurvature bounds exclude the parameter space, so coherently oscillating vector bosons produced by this mechanism are claimed to be unlikely dark-matter candidates.

Significance. If the no-go is correct, it is an interesting and potentially influential negative result: the isotropized multi-vector configuration was a natural way to avoid the anisotropy constraints that kill single-vector misalignment models, and the paper gives explicit thresholds that could be checked or falsified. The background and relic-abundance part of the paper is clear, the parameter counting is transparent, and the distinction between weak and strong mixing is physically well motivated. However, the decisive quantitative inputs—the power spectra, bispectra, and entropy spectra in Eqs. (31), (36), (39)-(43), (46), and (48)—are all cited from prior work rather than derived or independently checked here, and the strong-mixing isocurvature section contains an internal algebraic inconsistency. The central claim is therefore not yet established at the level of certainty required for a no-go statement; it is a conditional result pending resolution of these issues.

major comments (2)
  1. [Sec. IV C 2, Eqs. (48)-(50)] Equation (49) does not follow from Eq. (48). For large h, m_s^2 ≈ -8H^2 h^2, so the coefficient in Eq. (48) gives S/R ≈ -2√2/(3+2h^2) ≈ -√2/h^2, and hence P_S/P_R ≈ 2/h^4, not 2/h^2. This changes the isocurvature bound materially. With Eq. (49) as written and the stated beta<10^-4, one needs h>(2×10^4)^(1/2)≈141, not h>45. With the corrected ratio, beta<10^-4 gives h>(2×10^4)^(1/4)≈11.9. If the intended CMB bound is instead beta<10^-3 (which is the reading that reproduces h>45 from Eq. (49)), then the corrected ratio gives h>~6.7, which is compatible with the non-Gaussianity bound h<9.2 and removes the claimed incompatibility in the strong-mixing regime. The manuscript must either correct Eq. (49) and recompute the bounds, or justify Eq. (49) independently and reconcile it with Eq. (50).
  2. [Eqs. (31), (36), (39)-(43), (46), (48)] The central no-go claim rests entirely on perturbation spectra imported from the author's prior papers [27-30,37], with no derivation or numerical cross-check in this manuscript. This would be acceptable if the quoted results were standard and unambiguous, but the algebraic inconsistency between Eqs. (48) and (49) shows that the imported formulas are not being handled reliably. In particular, the strong-mixing amplitude in Eq. (48) and the exponential enhancement e^{2.37h} in Eq. (36) are load-bearing and not justified here. The paper should include at least a sketch of the key derivations or an explicit verification that the coefficients used here are exactly those in the cited papers, especially because the claimed no-go depends on close margins between the bounds.
minor comments (5)
  1. [Sec. IV A 1, Eq. (32)] The spectral-index shift requires h < sqrt(epsilon_H/(64 N_k)), i.e. for N_k~60, h < sqrt(epsilon_H/3840), not h < sqrt(epsilon_H/60) as stated. This affects the shaded region in Fig. 2 and the mass estimates in Sec. IV A, though it is not the main cause of the claimed incompatibility.
  2. [Sec. III B] The text says 'the vector field begins oscillate after reheating' in the case Gamma_phi < m_A, but this is the case where oscillation begins before reheating completes. Please correct the wording.
  3. [Section V] Typo: 'non-Guassianities' should be 'non-Gaussianities'; similarly, 'So for we have found' should be 'So far we have found'.
  4. [Sec. IV C] Typo: 'This is a massless field, so t is also expected' should be 'so it is also expected'.
  5. [Figs. 3 and 4] The captions 'Oscillate after reh. end' and related labels are too terse; please expand them to specify the reheating hierarchy and the excluded regions.

Circularity Check

1 steps flagged

Strong-mixing no-go is a load-bearing self-citation chain with an internally inconsistent imported amplitude; no construction-level circularity in the weak-mixing argument.

specific steps
  1. self citation load bearing [Sec. IV.C.2, Eqs. (48)-(50)]
    "For large h, we have the power spectrum of the entropy fluctuation PS ≃ 2/h2 PR ... Hence, the constraint on the isocurvature fluctuation [43] β ≡ PI/(PR+PI) < 10^-4 (anti-correlated) implies h > 45."

    The decisive strong-mixing isocurvature bound is the algebraic output of Eq. (50) applied to Eq. (49), and Eq. (49) is not derived in this paper; it is attributed to the same author's Ref. [28]. Moreover, Eq. (49) does not follow from the displayed Eq. (48): squaring Eq. (48) at large h gives P_S/P_R ∝ h^-4, not h^-2. Thus the h>45 exclusion is a numerical consequence of a self-cited, unverified amplitude rather than a self-contained derivation. Because the non-Gaussianity side (h<9.2) is also imported from the author's Ref. [29], the incompatibility is a conjunction of self-cited inputs; an O(1) change in the imported coefficient can make it disappear.

full rationale

No equation in the paper imposes the target conclusion by construction, and no parameter is fitted to force the exclusion. The weak-mixing constraints (h<3e-4 from f_NL=512h^2N^3, h>5.2e-3 from P_S=1-(56/3)h^2N^2) come from separate perturbation spectra and are not equivalent to each other; that half of the no-go is not circular and is robust against O(1) coefficient changes. The strong-mixing half, however, rests on formulas imported from the author's Refs. [27-30] without independent re-derivation, and the paper's own step from Eq. (48) to Eq. (49) is arithmetically inconsistent. The quoted h>45 is therefore inherited from a self-cited amplitude rather than established by the derivation shown here. This is a load-bearing self-citation/reliability issue rather than a pure construction-level circularity, hence a score of 4 rather than 6+.

Axiom & Free-Parameter Ledger

5 free parameters · 8 axioms · 0 invented entities

No new particles, forces, or fields are introduced. The paper works with standard massive vector fields, an inflaton, and known kinetic-coupling models. The heavy load is carried by imported perturbation results and by the choice of isotropized multi-vector background.

free parameters (5)
  • h (vector/inflaton mixing ratio)
    Free parameter encoding the kinetic-energy ratio; the whole exclusion is a scan over h. Derived from c and initial conditions on the attractor.
  • c (kinetic coupling parameter)
    Positive model parameter controlling f(ϕ); h ≃ sqrt((c-1)/2). Not determined by the model.
  • H_inf (inflationary Hubble scale)
    Treated as free when deriving relic abundance and constraints, with an upper bound from the tensor-to-scalar ratio.
  • T_reh (reheating temperature) = 10^12 GeV
    Fixed by hand to 10^12 GeV in the mass and constraint estimates; the relic abundance formulas depend on it.
  • N (number of vector fields)
    Required to be large for the isotropized attractor, but no concrete value or convergence check is given.
axioms (8)
  • domain assumption Isotropized background configuration A_i^{(a)} = A(t) δ_{ai} with many vector fields
    Eq. (2) is the model setup; it assumes a large number of randomly oriented vectors yields the attractor stated in Refs [24,31,32].
  • domain assumption Kinetic coupling f(ϕ) = exp(2c/M_pl² ∫ dϕ V/V_ϕ)
    Eq. (3) is the chosen coupling; it is an input model assumption rather than a consequence.
  • domain assumption Attractor f ∝ a⁻² is reached before CMB modes exit (N_back > 60)
    Assumed in Section IV so that the constraints apply during the attractor phase; if N_back < 60, all perturbation formulas would need revision.
  • domain assumption Light vector bosons during inflation: m_A/f ≪ H
    Used in Section II A to drop the mass term and integrate Eq. (8).
  • domain assumption Perturbation spectra and bispectra from Refs [27–30,37] are correct
    The central no-go depends on Eqs. (31), (36), (39), (40), (46), and (48)–(49), which are imported from the author's earlier work and not derived here.
  • domain assumption Longitudinal vector modes are blue-tilted and negligible
    Invoked in Section IV C, following Ref. [16].
  • standard math Standard WKB/coherent-oscillation treatment after inflation
    Eqs. (19)–(23) use standard homogeneous-oscillator techniques for massive fields.
  • domain assumption CMB bounds from Planck 2018 and BICEP/Keck are reliable
    The numerical constraints on P_R, β, r, and f_NL are drawn from Refs [43,44].

pith-pipeline@v1.3.0-alltime-deepseek · 12504 in / 18714 out tokens · 188408 ms · 2026-08-04T04:16:08.621037+00:00 · methodology

0 comments
read the original abstract

We present dark matter production by the misalignment mechanism of a multi-vector condensate through kinetic coupling during inflation. We impose isotropized background vector fields to release the model from the stringent constraint of anisotropy. However, it turns out that the constraints imposed by non-Gaussianity and isocurvature fluctuations are incompatible with each other, regardless of whether the fluctuations are in the weak-mixing or strong-mixing regime.

Figures

Figures reproduced from arXiv: 2607.14267 by Chong-Bin Chen.

Figure 1
Figure 1. Figure 1: FIG. 1. Comparison of the evolution of [PITH_FULL_IMAGE:figures/full_fig_p003_1.png] view at source ↗
Figure 2
Figure 2. Figure 2: FIG. 2. Constraints on the curvature fluctuation for [PITH_FULL_IMAGE:figures/full_fig_p005_2.png] view at source ↗
Figure 3
Figure 3. Figure 3: FIG. 3. Constraints on the curvature fluctuation for [PITH_FULL_IMAGE:figures/full_fig_p005_3.png] view at source ↗
Figure 4
Figure 4. Figure 4: FIG. 4. Constraints on the curvature fluctuation for [PITH_FULL_IMAGE:figures/full_fig_p006_4.png] view at source ↗

discussion (0)

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Reference graph

Works this paper leans on

45 extracted references · 40 linked inside Pith

  1. [1]

    P. W. Graham, J. Mardon, and S. Rajendran, Vector Dark Matter from Inflationary Fluctuations, Phys. Rev. D93, 103520 (2016), arXiv:1504.02102 [hep-ph]

  2. [2]

    orthogo- nal

    +O H 2 m2 A .(23) Therefore, in the deep coherent oscillation regime, the vector field behaves as non-relativistic matter with ⟨ρA⟩ ∝a−3, and can thus serve as a viable dark mat- ter candidate. III. RELIC ABUNDANCE OF DM After inflation ends, the universe begins reheating. We assume that reheating ends at timea reh, which is after 4 the end of inflation a...

  3. [3]

    ¨Ozsoy and G

    O. ¨Ozsoy and G. Tasinato, Vector dark matter, inflation, and non-minimal couplings with gravity, JCAP06, 003, arXiv:2310.03862 [astro-ph.CO]

  4. [4]

    Bastero-Gil, J

    M. Bastero-Gil, J. Santiago, L. Ubaldi, and R. Vega- Morales, Vector dark matter production at the end of inflation, JCAP04, 015, arXiv:1810.07208 [hep-ph]

  5. [5]

    Bastero-Gil, J

    M. Bastero-Gil, J. Santiago, R. Vega-Morales, and L. Ubaldi, Dark photon dark matter from a rolling in- flaton, JCAP02(02), 015, arXiv:2103.12145 [hep-ph]

  6. [6]

    R. T. Co, A. Pierce, Z. Zhang, and Y. Zhao, Dark Photon Dark Matter Produced by Axion Oscillations, Phys. Rev. D99, 075002 (2019), arXiv:1810.07196 [hep-ph]

  7. [7]

    J. A. Dror, K. Harigaya, and V. Narayan, Parametric Resonance Production of Ultralight Vector Dark Matter, Phys. Rev. D99, 035036 (2019), arXiv:1810.07195 [hep- ph]

  8. [8]

    Zhang, P

    H.-Y. Zhang, P. Arias, A. Cheek, E. D. Schiappacasse, L. Visinelli, and L. Roszkowski, Dark photon dark mat- ter from flattened axion potentials, JHEP10, 142, arXiv:2507.20484 [hep-ph]

  9. [9]

    Adshead, K

    P. Adshead, K. D. Lozanov, and Z. J. Weiner, Dark pho- ton dark matter from an oscillating dilaton, Phys. Rev. D107, 083519 (2023), arXiv:2301.07718 [hep-ph]

  10. [10]

    A. J. Long and L.-T. Wang, Dark Photon Dark Matter from a Network of Cosmic Strings, Phys. Rev. D99, 063529 (2019), arXiv:1901.03312 [hep-ph]

  11. [11]

    Kitajima and K

    N. Kitajima and K. Nakayama, Dark photon dark matter from cosmic strings and gravitational wave background, JHEP08, 068, arXiv:2212.13573 [hep-ph]

  12. [12]

    Nakai, R

    Y. Nakai, R. Namba, and Z. Wang, Light Dark Photon Dark Matter from Inflation, JHEP12, 170, arXiv:2004.10743 [hep-ph]

  13. [13]

    Firouzjahi, M

    H. Firouzjahi, M. A. Gorji, S. Mukohyama, and B. Sale- hian, Dark photon dark matter from charged inflaton, JHEP06, 050, arXiv:2011.06324 [hep-ph]

  14. [14]

    Salehian, M

    B. Salehian, M. A. Gorji, H. Firouzjahi, and S. Muko- hyama, Vector dark matter production from inflation with symmetry breaking, Phys. Rev. D103, 063526 (2021), arXiv:2010.04491 [hep-ph]

  15. [15]

    Nakai, R

    Y. Nakai, R. Namba, and I. Obata, Peaky produc- tion of light dark photon dark matter, JCAP08, 032, arXiv:2212.11516 [hep-ph]

  16. [16]

    A. E. Nelson and J. Scholtz, Dark Light, Dark Matter and the Misalignment Mechanism, Phys. Rev. D84, 103501 (2011), arXiv:1105.2812 [hep-ph]

  17. [17]

    Nakayama, Vector Coherent Oscillation Dark Matter, JCAP10, 019, arXiv:1907.06243 [hep-ph]

    K. Nakayama, Vector Coherent Oscillation Dark Matter, JCAP10, 019, arXiv:1907.06243 [hep-ph]

  18. [18]

    Nakayama, Constraint on Vector Coherent Oscilla- tion Dark Matter with Kinetic Function, JCAP08, 033, arXiv:2004.10036 [hep-ph]

    K. Nakayama, Constraint on Vector Coherent Oscilla- tion Dark Matter with Kinetic Function, JCAP08, 033, arXiv:2004.10036 [hep-ph]

  19. [19]

    Kitajima and K

    N. Kitajima and K. Nakayama, Viable vector coherent oscillation dark matter, JCAP07, 014, arXiv:2303.04287 [hep-ph]

  20. [20]

    Kaneta, H.-S

    K. Kaneta, H.-S. Lee, J. Lee, and J. Yi, Misalignment mechanism for a mass-varying vector boson, JCAP09, 017, arXiv:2306.01291 [astro-ph.CO]

  21. [21]

    Fujita, K

    T. Fujita, K. Murai, K. Nakayama, and W. Yin, Mis- alignment production of vector boson dark matter from axion-SU(2) inflation, JCAP04, 007, arXiv:2312.06889 [hep-ph]

  22. [22]

    M. a. Watanabe, S. Kanno, and J. Soda, Inflationary Universe with Anisotropic Hair, Phys. Rev. Lett.102, 191302 (2009), arXiv:0902.2833 [hep-th]

  23. [23]

    M. a. Watanabe, S. Kanno, and J. Soda, The Nature of Primordial Fluctuations from Anisotropic Inflation, Prog. Theor. Phys.123, 1041 (2010), arXiv:1003.0056 [astro-ph.CO]

  24. [24]

    Kanno, J

    S. Kanno, J. Soda, and M. a. Watanabe, Anisotropic Power-law Inflation, JCAP12, 024, arXiv:1010.5307 [hep-th]

  25. [25]

    Yamamoto, M

    K. Yamamoto, M. a. Watanabe, and J. Soda, Inflation with Multi-Vector-Hair: The Fate of Anisotropy, Class. Quant. Grav.29, 145008 (2012), arXiv:1201.5309 [hep- th]

  26. [26]

    Maleknejad, M

    A. Maleknejad, M. M. Sheikh-Jabbari, and J. Soda, 10 Gauge Fields and Inflation, Phys. Rept.528, 161 (2013), arXiv:1212.2921 [hep-th]

  27. [27]

    Chen and J

    C.-B. Chen and J. Soda, Anisotropic hyperbolic inflation, JCAP09, 026, arXiv:2106.04813 [hep-th]

  28. [28]

    Chen and J

    C.-B. Chen and J. Soda, Geometric structure of multi- form-field isotropic inflation and primordial fluctuations, JCAP05(05), 029, arXiv:2201.03160 [hep-th]

  29. [29]

    Chen, Inflation with vector fields revisited: heavy entropy perturbations and primordial black holes, JCAP 11, 063, arXiv:2312.06105 [astro-ph.CO]

    C.-B. Chen, Inflation with vector fields revisited: heavy entropy perturbations and primordial black holes, JCAP 11, 063, arXiv:2312.06105 [astro-ph.CO]

  30. [30]

    Chen, Inflation with vector fields revisited: non- Gaussianities, (2026), arXiv:2605.28752 [hep-th]

    C.-B. Chen, Inflation with vector fields revisited: non- Gaussianities, (2026), arXiv:2605.28752 [hep-th]

  31. [31]

    Chen, B.-X

    C.-B. Chen, B.-X. An, and F.-W. Shu, Primordial black holes with anisotropic hair, Phys. Rev. D112, 10 (2025), arXiv:2507.16807 [astro-ph.CO]

  32. [32]

    M. C. Bento, O. Bertolami, P. V. Moniz, J. M. Mourao, and P. M. Sa, On the cosmology of massive vector fields with SO(3) global symmetry, Class. Quant. Grav.10, 285 (1993), arXiv:gr-qc/9302034

  33. [33]

    Golovnev, V

    A. Golovnev, V. Mukhanov, and V. Vanchurin, Vector Inflation, JCAP06, 009, arXiv:0802.2068 [astro-ph]

  34. [34]

    Maleknejad and M

    A. Maleknejad and M. M. Sheikh-Jabbari, Non-Abelian Gauge Field Inflation, Phys. Rev. D84, 043515 (2011), arXiv:1102.1932 [hep-ph]

  35. [35]

    Maleknejad and M

    A. Maleknejad and M. M. Sheikh-Jabbari, Gauge-flation: Inflation From Non-Abelian Gauge Fields, Phys. Lett. B 723, 224 (2013), arXiv:1102.1513 [hep-ph]

  36. [36]

    Demozzi, V

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

  37. [37]

    Firouzjahi, M

    H. Firouzjahi, M. A. Gorji, S. A. Hosseini Mansoori, A. Karami, and T. Rostami, Charged Vector Inflation, Phys. Rev. D100, 043530 (2019), arXiv:1812.07464 [hep- th]

  38. [38]

    M. A. Gorji, S. A. Hosseini Mansoori, and H. Firouz- jahi, Inflation with multiple vector fields and non- Gaussianities, JCAP11, 041, arXiv:2008.08195 [astro- ph.CO]

  39. [39]

    Ratra, Expressions for linearized perturbations in a massive scalar field dominated cosmological model, Phys

    B. Ratra, Expressions for linearized perturbations in a massive scalar field dominated cosmological model, Phys. Rev. D44, 352 (1991)

  40. [40]

    Hwang, Roles of a coherent scalar field on the evolu- tion of cosmic structures, Phys

    J.-c. Hwang, Roles of a coherent scalar field on the evolu- tion of cosmic structures, Phys. Lett. B401, 241 (1997), arXiv:astro-ph/9610042

  41. [41]

    Hwang and H

    J.-c. Hwang and H. Noh, Axion as a Cold Dark Matter candidate, Phys. Lett. B680, 1 (2009), arXiv:0902.4738 [astro-ph.CO]

  42. [42]

    Kofman, A

    L. Kofman, A. D. Linde, and A. A. Starobinsky, Towards the theory of reheating after inflation, Phys. Rev. D56, 3258 (1997), arXiv:hep-ph/9704452

  43. [43]

    Braden, L

    J. Braden, L. Kofman, and N. Barnaby, Reheating the Universe After Multi-Field Inflation, JCAP07, 016, arXiv:1005.2196 [hep-th]

  44. [44]

    Akramiet al.(Planck), Planck 2018 results

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

  45. [45]

    P. A. R. Adeet al.(BICEP, Keck), Improved Con- straints on Primordial Gravitational Waves using Planck, WMAP, and BICEP/Keck Observations through the 2018 Observing Season, Phys. Rev. Lett.127, 151301 (2021), arXiv:2110.00483 [astro-ph.CO]