pith. sign in

arxiv: 2605.28054 · v1 · pith:BSZG7HSYnew · submitted 2026-05-27 · ✦ hep-th · astro-ph.CO· gr-qc· hep-ph

Fermionic Bubble Loop in Cosmological Collider Revisited: Exact signals from spectral and Mellin-Barnes methods

Shuntaro Aoki , Zhehan Qin , Masahide Yamaguchi , Yuhang Zhu This is my paper

Pith reviewed 2026-06-29 11:27 UTC · model grok-4.3

classification ✦ hep-th astro-ph.COgr-qchep-ph
keywords fermionic bubble loopcosmological colliderbispectrum signalspectral decompositionMellin-Barnes representationYukawa interactionfield redefinitionexact loop computation
0
0 comments X

The pith

Fermionic bubble loops contribute a vanishing bispectrum signal to cosmological collider observables under Yukawa couplings.

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

The paper derives an exact expression for the contribution of a fermionic bubble loop to the cosmological bispectrum for arbitrary coupling strengths. Two independent techniques are used: one decomposes the loop via an identity on the product of propagators into an infinite sum of tree-level exchanges, while the other reconstructs the result from residues of Mellin-Barnes contour integrals. The two results agree. For the phenomenologically relevant case of Yukawa interactions between fermions and the inflaton, the bispectrum signal is shown to vanish identically, with the spectral method tracing the cancellation to a field redefinition that relates the loop diagram to its tree-level counterparts.

Core claim

We provide an exact answer for arbitrary couplings to the fermionic bubble loop signal in cosmological collider physics. The resulting bispectrum signal vanishes identically for Yukawa interactions. Through the spectral decomposition, this vanishing can be traced to a field redefinition of the associated tree-level counterparts. The result is also shown to follow from applying differential operators to the corresponding scalar bubble.

What carries the argument

The spectral decomposition identity for the product of propagators that converts the bubble diagram into a sum of tree-level exchange signals, together with Mellin-Barnes contour integration over families of poles.

If this is right

  • The bispectrum signal from fermionic bubble loops vanishes identically under Yukawa interactions with the inflaton.
  • The vanishing is explained by a field redefinition that equates the loop to tree-level processes.
  • The fermionic bubble result follows from the scalar bubble result by the action of differential operators.
  • The two analytic methods agree for arbitrary couplings, confirming the exact vanishing.

Where Pith is reading between the lines

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

  • The propagator identity technique may reduce other one-loop diagrams in de Sitter space to sums of trees.
  • Similar field-redefinition cancellations could appear in multi-field inflationary models containing fermions.
  • The Mellin-Barnes residue families might be reusable for computing higher-point or multi-loop correlators.

Load-bearing premise

The propagator product identity holds in the cosmological background and the Mellin-Barnes contours can be closed without missing contributions for the kinematics considered.

What would settle it

A numerical evaluation of the loop integral for concrete values of the fermion mass, inflaton mass, and Yukawa coupling that yields a non-zero bispectrum coefficient.

Figures

Figures reproduced from arXiv: 2605.28054 by Masahide Yamaguchi, Shuntaro Aoki, Yuhang Zhu, Zhehan Qin.

Figure 1
Figure 1. Figure 1: The SK diagrams for four-point and three-point correlation functions with the fermionic bubble loop. Here the vertices marked by • represent either time-ordered vertex (la￾belled by black •) or anti-time-ordered vertex (labelled by white ◦). For generality, we allow two internal fermion propagators to carry different masses m1 and m2, respectively. As shown in [PITH_FULL_IMAGE:figures/full_fig_p009_1.png] view at source ↗
Figure 2
Figure 2. Figure 2: The location of different poles that contribute to the si contour integrals. Non-local Signal Different poles contribute to different parts of the result, according to their distinct analytic structures. Let us begin with the non-local CC signal, which is non-analytic in the internal momentum |s| = |k1 + k2|. In the factorised seed function (3.56), the s dependence appears as s −2s1234 , arising from the f… view at source ↗
Figure 3
Figure 3. Figure 3: The signals from the fermionic bubble loop obtained using two different methods. We take the parameters q1 = q2 = −2. Left panel: The non-local signals, with the kinematic variables set to r1 = r2/2 ≡ r. The solid curves are obtained with the spectral method, shown in green for m1 = 3, m2 = 2 and in purple for m1 = 3, m2 = 1. The corresponding MB results are marked by gray dots with the same mass choices. … view at source ↗
Figure 4
Figure 4. Figure 4: The tree-level three-point correlator from massive scalar exchange with a φσ coupling. As shown in the previous section, bubble diagrams can be decomposed into a series of corre￾sponding tree-level diagrams with massive propagators of different masses. For the Yukawa-type fermionic bubble, the relevant tree-level building blocks are those involving the λφσ coupling. To understand the disappearance of the C… view at source ↗
read the original abstract

Fermionic degrees of freedom are essential ingredients in cosmological collider physics and are well motivated by many phenomenological models beyond the Standard Model, but their signals remain largely unexplored due to the difficulty of computing loop diagrams. In this work, we ask how fermionic bubble loops contribute to cosmological collider signals and provide an exact answer for arbitrary couplings. We develop two parallel analytical methods whose agreement provides a non-trivial check of the result. The first method is similar in spirit to spectral decomposition and is built directly from an identity for the product of propagators, which turns the bubble signal into an infinite sum of tree-level exchange signals. The second method is based on the Mellin-Barnes representation, where the result is reconstructed from the residues of distinct families of poles. We also show that the fermionic bubble can be generated from the scalar bubble by the action of appropriate differential operators. As a phenomenologically important application, we consider Yukawa interactions between fermions and the inflaton, finding that the resulting bispectrum signal vanishes identically. Through the spectral decomposition, this vanishing can be traced to a field redefinition of the associated tree-level counterparts.

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

2 major / 2 minor

Summary. The manuscript computes the contribution of fermionic bubble loops to the bispectrum in cosmological collider physics. It develops two independent analytical techniques: (i) a spectral decomposition that uses an identity for the product of two fermionic propagators to rewrite the bubble diagram as an infinite sum of tree-level exchange diagrams, and (ii) a Mellin-Barnes contour-integral representation whose residues are summed to reconstruct the same result. The two methods are shown to agree for arbitrary couplings. As a phenomenological application, the authors consider Yukawa interactions between fermions and the inflaton and conclude that the resulting bispectrum vanishes identically; the spectral method traces this vanishing to a field redefinition that relates the loop to its tree-level counterpart.

Significance. If the central results hold, the work supplies an exact, closed-form expression for a class of loop diagrams that have previously been intractable in de Sitter space. The explicit demonstration that the Yukawa-induced signal vanishes, together with the dual-method consistency check, constitutes a concrete advance for model-building in inflationary cosmology. The use of propagator identities and residue calculus to obtain parameter-free results is a methodological strength.

major comments (2)
  1. [§2] §2 (spectral decomposition) and the paragraph following Eq. (identity for propagator product): the reduction of the bubble to a sum of tree exchanges assumes that the propagator-product identity holds without additional surface terms arising from the time-ordered integrals or the specific form of the Bunch-Davies mode functions. This assumption is load-bearing for both the general result and the subsequent claim of identical vanishing under Yukawa coupling; an explicit verification that no such surface terms appear for the chosen kinematics and masses is required.
  2. [§4] §4 (Mellin-Barnes method): the reconstruction from residues relies on closing the contours at infinity without capturing extra poles or non-vanishing arc contributions. The manuscript should supply a concrete estimate or explicit check that the arcs vanish for the relevant mass range and external momenta; this is necessary to confirm that the agreement with the spectral method is not an artifact of shared contour assumptions.
minor comments (2)
  1. Notation for the fermionic propagators and the differential operators that map the scalar bubble to the fermionic one should be collected in a single table or appendix for clarity.
  2. The statement that the signal 'vanishes identically' would benefit from an explicit statement of the kinematic regime (e.g., squeezed limit, equal-time correlator) in which the vanishing is demonstrated.

Simulated Author's Rebuttal

2 responses · 0 unresolved

We thank the referee for the careful reading and constructive comments. The two major comments concern the rigor of our analytical methods. We address each below, agreeing that additional explicit checks will strengthen the presentation, and indicate the revisions to be made.

read point-by-point responses

  1. Referee: [§2] §2 (spectral decomposition) and the paragraph following Eq. (identity for propagator product): the reduction of the bubble to a sum of tree exchanges assumes that the propagator-product identity holds without additional surface terms arising from the time-ordered integrals or the specific form of the Bunch-Davies mode functions. This assumption is load-bearing for both the general result and the subsequent claim of identical vanishing under Yukawa coupling; an explicit verification that no such surface terms appear for the chosen kinematics and masses is required.

    Authors: We agree that an explicit verification strengthens the result. The propagator-product identity follows directly from the mode-function expansion of the fermionic propagators in de Sitter space. When inserted into the in-in time integrals, the Bunch-Davies boundary conditions ensure that any candidate surface terms at early conformal times are exponentially suppressed by the oscillatory factors and the iε prescription. We have performed a direct numerical check for representative fermion masses (m_f = 0.5, 1.5) and external momenta satisfying the bispectrum kinematics, confirming that the integrated surface contributions are numerically zero within machine precision. We will add this verification as a short appendix in the revised manuscript. revision: yes

  2. Referee: [§4] §4 (Mellin-Barnes method): the reconstruction from residues relies on closing the contours at infinity without capturing extra poles or non-vanishing arc contributions. The manuscript should supply a concrete estimate or explicit check that the arcs vanish for the relevant mass range and external momenta; this is necessary to confirm that the agreement with the spectral method is not an artifact of shared contour assumptions.

    Authors: The contour closure is justified by the asymptotic decay of the Gamma-function products in the Mellin-Barnes integrand, which falls faster than any power for Re(s) → ±∞ when the fermion mass satisfies m_f > 0 and the external momenta obey the triangle inequalities. Because the spectral method (which never uses contours) reproduces the identical closed-form expression for arbitrary couplings, any missed arc or pole contribution would have to cancel exactly between the two independent derivations—an unlikely coincidence. To make the arc estimate explicit, we will insert a short paragraph in §4 of the revised version giving the leading Stirling bound on the arc integral, showing it is suppressed by at least two orders of magnitude relative to the residue sum for the phenomenologically relevant parameter window. revision: yes

Circularity Check

0 steps flagged

No significant circularity; derivation relies on independent mathematical identities

full rationale

The paper derives its central results (exact fermionic bubble signals and their vanishing under Yukawa coupling) from an identity converting the bubble into a sum of tree exchanges plus Mellin-Barnes residue reconstruction. These are standard contour-integral and propagator identities applied to the cosmological background, with the two methods providing an internal cross-check rather than a self-referential loop. The vanishing is attributed to a field redefinition of tree-level diagrams, which is a direct algebraic consequence of the interaction structure and does not reduce the result to fitted inputs or prior self-citations. No load-bearing step equates a prediction to its own definition or fitted parameter by construction.

Axiom & Free-Parameter Ledger

0 free parameters · 1 axioms · 0 invented entities

No free parameters, new entities, or ad-hoc assumptions are mentioned in the abstract; the work rests on standard QFT propagator identities and contour-integration techniques.

axioms (1)
  • standard math Standard identities for products of propagators and residue theorems for Mellin-Barnes integrals hold in de Sitter or quasi-de Sitter backgrounds.
    Invoked to convert the bubble diagram into sums or residues.

pith-pipeline@v0.9.1-grok · 5748 in / 1255 out tokens · 38993 ms · 2026-06-29T11:27:18.508308+00:00 · methodology

discussion (0)

Sign in with ORCID, Apple, or X to comment. Anyone can read and Pith papers without signing in.

Forward citations

Cited by 2 Pith papers

Reviewed papers in the Pith corpus that reference this work. Sorted by Pith novelty score.

  1. On-Shell Bootstrap of Loop Inflation Correlators with Spectral Dispersion

    hep-th 2026-06 unverdicted novelty 7.0

    Introduces spectral dispersion bootstrap combining dS spectral decomposition and dispersion relations to compute 3- and 4-point loop correlators with massive scalar and vector exchanges.

  2. On Cosmological Correlators with Boundary Contributions

    gr-qc 2026-06 unverdicted novelty 6.0

    The paper derives a correspondence between boundary terms and field redefinitions for cosmological correlators and classifies non-vanishing boundary contributions in massive-exchange diagrams under dS isometries and b...

Reference graph

Works this paper leans on

138 extracted references · 131 canonical work pages · cited by 2 Pith papers · 31 internal anchors

  1. [1]

    Quasi-Single Field Inflation and Non-Gaussianities

    X. Chen and Y. Wang,Quasi-Single Field Inflation and Non-Gaussianities,JCAP04 (2010) 027 [0911.3380]

    work page internal anchor Pith review Pith/arXiv arXiv 2010

  2. [2]

    Signatures of Supersymmetry from the Early Universe

    D. Baumann and D. Green,Signatures of Supersymmetry from the Early Universe,Phys. Rev. D85(2012) 103520 [1109.0292]

    work page internal anchor Pith review Pith/arXiv arXiv 2012

  3. [3]

    Effective field theory approach to quasi-single field inflation and effects of heavy fields

    T. Noumi, M. Yamaguchi and D. Yokoyama,Effective field theory approach to quasi-single field inflation and effects of heavy fields,JHEP06(2013) 051 [1211.1624]

    work page internal anchor Pith review Pith/arXiv arXiv 2013

  4. [4]

    Cosmological Collider Physics

    N. Arkani-Hamed and J. Maldacena,Cosmological Collider Physics,1503.08043

    work page internal anchor Pith review Pith/arXiv arXiv

  5. [5]

    J.-O. Gong, S. Pi and M. Sasaki,Equilateral non-Gaussianity from heavy fields,JCAP11 (2013) 043 [1306.3691]

    work page internal anchor Pith review Pith/arXiv arXiv 2013

  6. [6]

    Quantum Primordial Standard Clocks

    X. Chen, M.H. Namjoo and Y. Wang,Quantum Primordial Standard Clocks,JCAP02 (2016) 013 [1509.03930]

    work page internal anchor Pith review Pith/arXiv arXiv 2016

  7. [7]

    X. Chen, Y. Wang and Z.-Z. Xianyu,Standard Model Background of the Cosmological Collider,Phys. Rev. Lett.118(2017) 261302 [1610.06597]. 50

    work page internal anchor Pith review Pith/arXiv arXiv 2017

  8. [8]

    H. Lee, D. Baumann and G.L. Pimentel,Non-Gaussianity as a Particle Detector,JHEP 12(2016) 040 [1607.03735]

    work page internal anchor Pith review Pith/arXiv arXiv 2016

  9. [9]

    H. An, M. McAneny, A.K. Ridgway and M.B. Wise,Quasi Single Field Inflation in the non-perturbative regime,JHEP06(2018) 105 [1706.09971]

    work page internal anchor Pith review Pith/arXiv arXiv 2018

  10. [10]

    Arkani-Hamed, D

    N. Arkani-Hamed, D. Baumann, H. Lee and G.L. Pimentel,The Cosmological Bootstrap: Inflationary Correlators from Symmetries and Singularities,JHEP04(2020) 105 [1811.00024]

    work page arXiv 2020

  11. [11]

    S. Lu, Y. Wang and Z.-Z. Xianyu,A Cosmological Higgs Collider,JHEP02(2020) 011 [1907.07390]

    work page arXiv 2020

  12. [12]

    A. Hook, J. Huang and D. Racco,Searches for other vacua. Part II. A new Higgstory at the cosmological collider,JHEP01(2020) 105 [1907.10624]

    work page arXiv 2020

  13. [13]

    T. Liu, X. Tong, Y. Wang and Z.-Z. Xianyu,Probing P and CP Violations on the Cosmological Collider,JHEP04(2020) 189 [1909.01819]

    work page arXiv 2020

  14. [14]

    Kumar and R

    S. Kumar and R. Sundrum,Cosmological Collider Physics and the Curvaton,JHEP04 (2020) 077 [1908.11378]

    work page arXiv 2020

  15. [15]

    Wang and Z.-Z

    L.-T. Wang and Z.-Z. Xianyu,In Search of Large Signals at the Cosmological Collider, JHEP02(2020) 044 [1910.12876]

    work page arXiv 2020

  16. [16]

    Wang and Z.-Z

    L.-T. Wang and Z.-Z. Xianyu,Gauge Boson Signals at the Cosmological Collider,JHEP 11(2020) 082 [2004.02887]

    work page arXiv 2020

  17. [17]

    Aoki and M

    S. Aoki and M. Yamaguchi,Disentangling mass spectra of multiple fields in cosmological collider,JHEP04(2021) 127 [2012.13667]

    work page arXiv 2021

  18. [18]

    Pinol, S

    L. Pinol, S. Aoki, S. Renaux-Petel and M. Yamaguchi,Inflationary flavor oscillations and the cosmic spectroscopy,Phys. Rev. D107(2023) L021301 [2112.05710]

    work page arXiv 2023

  19. [19]

    Cui and Z.-Z

    Y. Cui and Z.-Z. Xianyu,Probing Leptogenesis with the Cosmological Collider,Phys. Rev. Lett.129(2022) 111301 [2112.10793]

    work page arXiv 2022

  20. [20]

    Reece, L.-T

    M. Reece, L.-T. Wang and Z.-Z. Xianyu,Large-field inflation and the cosmological collider,Phys. Rev. D107(2023) L101304 [2204.11869]

    work page arXiv 2023

  21. [21]

    X. Chen, R. Ebadi and S. Kumar,Classical cosmological collider physics and primordial features,JCAP08(2022) 083 [2205.01107]

    work page arXiv 2022

  22. [22]

    Qin and Z.-Z

    Z. Qin and Z.-Z. Xianyu,Phase information in cosmological collider signals,JHEP10 (2022) 192 [2205.01692]

    work page arXiv 2022

  23. [23]

    Aoki,Continuous spectrum on cosmological collider,JCAP04(2023) 002 [2301.07920]

    S. Aoki,Continuous spectrum on cosmological collider,JCAP04(2023) 002 [2301.07920]. 51

    work page arXiv 2023

  24. [24]

    Jazayeri, S

    S. Jazayeri, S. Renaux-Petel and D. Werth,Shapes of the cosmological low-speed collider, JCAP12(2023) 035 [2307.01751]

    work page arXiv 2023

  25. [25]

    Jazayeri, S

    S. Jazayeri, S. Renaux-Petel, X. Tong, D. Werth and Y. Zhu,Parity violation from emergent nonlocality during inflation,Phys. Rev. D108(2023) 123523 [2308.11315]

    work page arXiv 2023

  26. [26]

    Pinol, S

    L. Pinol, S. Renaux-Petel and D. Werth,The cosmological flow: a systematic approach to primordial correlators,JCAP02(2025) 019 [2312.06559]

    work page arXiv 2025

  27. [27]

    Ema and S

    Y. Ema and S. Verner,Cosmological collider signatures of Higgs-R 2 inflation,JCAP04 (2024) 039 [2309.10841]

    work page arXiv 2024

  28. [28]

    X. Tong, Y. Wang, C. Zhang and Y. Zhu,BCS in the sky: signatures of inflationary fermion condensation,JCAP04(2024) 022 [2304.09428]

    work page arXiv 2024

  29. [29]

    Chakraborty and J

    P. Chakraborty and J. Stout,Compact scalars at the cosmological collider,JHEP03 (2024) 149 [2311.09219]

    work page arXiv 2024

  30. [30]

    S. Aoki, A. Ghoshal and A. Strumia,Cosmological collider non-Gaussianity from multiple scalars and R 2 gravity,JHEP11(2024) 009 [2408.07069]

    work page arXiv 2024

  31. [31]

    Wu,The cosmological collider in R 2 inflation,JCAP07(2024) 010 [2404.05031]

    Y.-P. Wu,The cosmological collider in R 2 inflation,JCAP07(2024) 010 [2404.05031]

    work page arXiv 2024

  32. [32]

    Craig, S

    N. Craig, S. Kumar and A. McCune,An effective cosmological collider,JHEP07(2024) 108 [2401.10976]

    work page arXiv 2024

  33. [33]

    McCulloch, E

    C. McCulloch, E. Pajer and X. Tong,A cosmological tachyon collider: enhancing the long-short scale coupling,JHEP05(2024) 262 [2401.11009]

    work page arXiv 2024

  34. [34]

    The UV Sensitivity of Axion Monodromy Inflation

    E. Pajer, D.-G. Wang and B. Zhang,The UV Sensitivity of Axion Monodromy Inflation, SciPost Phys.20(2026) 097 [2412.05762]

    work page internal anchor Pith review Pith/arXiv arXiv 2026

  35. [35]

    Wang and B

    D.-G. Wang and B. Zhang,Bootstrapping the cosmological collider with resonant features, JHEP09(2025) 122 [2505.19066]

    work page arXiv 2025

  36. [36]

    Testing the arrow of time at the cosmo collider,

    S. Aoki and A. Strumia,Testing the arrow of time at the cosmo collider,JCAP03(2026) 067 [2510.05204]

    work page arXiv 2026

  37. [37]

    Kumar and M

    S. Kumar and M. Nee,Warped dimensions at the cosmological collider,JHEP04(2026) 035 [2510.19900]

    work page arXiv 2026

  38. [38]

    Every Wrinkle Carries A Memory: An Integro-differential Bootstrap for Features in Cosmological Correlators

    S. Jazayeri, X. Tong and Y. Zhu,Every Wrinkle Carries A Memory: An Integro-differential Bootstrap for Features in Cosmological Correlators,2511.00152

    work page internal anchor Pith review Pith/arXiv arXiv

  39. [39]

    Xianyu and J

    Z.-Z. Xianyu and J. Zang,Massive inflationary amplitudes: new representations and degenerate limits,JHEP03(2026) 122 [2511.08677]

    work page arXiv 2026

  40. [40]

    Colas, Z

    T. Colas, Z. Qin and X. Tong,Open Effective Field Theory and the Physics of Cosmological Collider Signals,2512.07941. 52

    work page arXiv

  41. [41]

    Bodas, E

    A. Bodas, E. Broadberry, R. Sundrum and Z. Xu,Charged loops at the cosmological collider with chemical potential,JHEP01(2026) 083 [2507.22978]

    work page arXiv 2026

  42. [42]

    Cheung and D

    T. Cheung and D. Stefanyszyn,Massive Spinning Fields During Inflation: Feynman rules and correlator comparison,2509.08888

    work page arXiv

  43. [43]

    Amplifying the Cosmological Collider with Ghost Spectators

    M.C. Ferreira, F.T. Falciano and G.L. Pimentel,Amplifying the Cosmological Collider with Ghost Spectators,2601.14413

    work page internal anchor Pith review Pith/arXiv arXiv

  44. [44]

    Cabass, O.H.E

    G. Cabass, O.H.E. Philcox, M.M. Ivanov, K. Akitsu, S.-F. Chen, M. Simonovi´ c et al., BOSS constraints on massive particles during inflation: The cosmological collider in action,Phys. Rev. D111(2025) 063510 [2404.01894]

    work page arXiv 2025

  45. [45]

    Goldstein, O.H.E

    S. Goldstein, O.H.E. Philcox, J.C. Hill and L. Hui,Intermediate mass-range particles from small scales: Nonperturbative techniques for cosmological collider physics from large-scale structure surveys,Phys. Rev. D110(2024) 083516 [2407.08731]

    work page arXiv 2024

  46. [46]

    Sohn, D.-G

    W. Sohn, D.-G. Wang, J.R. Fergusson and E.P.S. Shellard,Searching for cosmological collider in the Planck CMB data,JCAP09(2024) 016 [2404.07203]

    work page arXiv 2024

  47. [47]

    Goldstein, O.H.E

    S. Goldstein, O.H.E. Philcox, E. Fondi and W.R. Coulton,Wonderings on wiggly bispectra: Nonlinear evolution and reconstruction of oscillations in the squeezed bispectrum,Phys. Rev. D112(2025) 083503 [2505.13443]

    work page arXiv 2025

  48. [48]

    Anbajagane and H

    D. Anbajagane and H. Lee,Primordial Physics in the Nonlinear Universe: mapping cosmological collider models to weak-lensing observables,2509.02693

    work page arXiv

  49. [49]

    Suman, D.-G

    P. Suman, D.-G. Wang, W. Sohn, J.R. Fergusson and E.P.S. Shellard,Searching for Cosmological Collider in the Planck CMB Data II: collider templates and Modal analysis, 2512.22085

    work page arXiv

  50. [50]

    Green, J

    D. Green, J. Han and B. Wallisch,Extending the Cosmological Collider: New Scaling Regimes and Constraints from BOSS,2602.12232

    work page arXiv

  51. [51]

    Kumar, Q

    S. Kumar, Q. Lu, Z.-Z. Xianyu and Y. Zhang,Cosmological Collider Searches beyond the Hubble Scale with Planck Data,2603.15728

    work page arXiv

  52. [52]

    Philcox, G.L

    O.H.E. Philcox, G.L. Pimentel and C. Yang,Searching for Unparticles with the Cosmic Microwave Background,2603.13486

    work page arXiv

  53. [53]

    Scalars at the Cosmological Collider: Full Shapes of Tree Diagrams and Bispectrum Searches using Planck Data

    S. Kumar, Q. Lu, Z.-Z. Xianyu and Y. Zhang,Scalars at the Cosmological Collider: Full Shapes of Tree Diagrams and Bispectrum Searches using Planck Data,2604.07434

    work page internal anchor Pith review Pith/arXiv arXiv

  54. [54]

    Non-Relativistic Cosmological Collider Signals

    M.C. Ferreira and F.T. Falciano,Non-Relativistic Cosmological Collider Signals, 2605.20102

    work page internal anchor Pith review Pith/arXiv arXiv

  55. [55]

    J. You, L. Song, C. Han, H.-J. He, X. Chen and Z.-Z. Xianyu,Cosmological Collider Signatures from Right-Handed Neutrino Loop,2605.21419. 53

    work page internal anchor Pith review Pith/arXiv arXiv

  56. [56]

    X. Chen, Y. Wang and Z.-Z. Xianyu,Schwinger-Keldysh Diagrammatics for Primordial Perturbations,JCAP12(2017) 006 [1703.10166]

    work page internal anchor Pith review Pith/arXiv arXiv 2017

  57. [57]

    Qin and Z.-Z

    Z. Qin and Z.-Z. Xianyu,Helical inflation correlators: partial Mellin-Barnes and bootstrap equations,JHEP04(2023) 059 [2208.13790]

    work page arXiv 2023

  58. [58]

    S. Aoki, T. Noumi, F. Sano and M. Yamaguchi,Analytic formulae for inflationary correlators with dynamical mass,JHEP03(2024) 073 [2312.09642]

    work page arXiv 2024

  59. [59]

    Stefanyszyn, X

    D. Stefanyszyn, X. Tong and Y. Zhu,Cosmological correlators through the looking glass: reality, parity, and factorisation,JHEP05(2024) 196 [2309.07769]

    work page arXiv 2024

  60. [60]

    Baumann, C

    D. Baumann, C. Duaso Pueyo, A. Joyce, H. Lee and G.L. Pimentel,The cosmological bootstrap: weight-shifting operators and scalar seeds,JHEP12(2020) 204 [1910.14051]

    work page arXiv 2020

  61. [61]

    Baumann, C

    D. Baumann, C. Duaso Pueyo, A. Joyce, H. Lee and G.L. Pimentel,The Cosmological Bootstrap: Spinning Correlators from Symmetries and Factorization,SciPost Phys.11 (2021) 071 [2005.04234]

    work page arXiv 2021

  62. [62]

    Baumann, D

    D. Baumann, D. Green, A. Joyce, E. Pajer, G.L. Pimentel, C. Sleight et al.,Snowmass White Paper: The Cosmological Bootstrap,SciPost Phys. Comm. Rep.2024(2024) 1 [2203.08121]

    work page arXiv 2024

  63. [63]

    Pimentel and D.-G

    G.L. Pimentel and D.-G. Wang,Boostless cosmological collider bootstrap,JHEP10(2022) 177 [2205.00013]

    work page arXiv 2022

  64. [64]

    Jazayeri and S

    S. Jazayeri and S. Renaux-Petel,Cosmological bootstrap in slow motion,JHEP12(2022) 137 [2205.10340]

    work page arXiv 2022

  65. [65]

    Wang, G.L

    D.-G. Wang, G.L. Pimentel and A. Ach´ ucarro,Bootstrapping multi-field inflation: non-Gaussianities from light scalars revisited,JCAP05(2023) 043 [2212.14035]

    work page arXiv 2023

  66. [66]

    Qin and Z.-Z

    Z. Qin and Z.-Z. Xianyu,Closed-form formulae for inflation correlators,JHEP07(2023) 001 [2301.07047]

    work page arXiv 2023

  67. [67]

    S. Aoki, L. Pinol, F. Sano, M. Yamaguchi and Y. Zhu,Cosmological correlators with double massive exchanges: bootstrap equation and phenomenology,JHEP09(2024) 176 [2404.09547]

    work page arXiv 2024

  68. [68]

    Liu and Z.-Z

    H. Liu and Z.-Z. Xianyu,Massive inflationary amplitudes: differential equations and complete solutions for general trees,JHEP09(2025) 183 [2412.07843]

    work page arXiv 2025

  69. [69]

    Z. Qin, S. Renaux-Petel, X. Tong, D. Werth and Y. Zhu,The exact and approximate tales of boost-breaking cosmological correlators,JCAP09(2025) 058 [2506.01555]

    work page arXiv 2025

  70. [70]

    Sleight,A Mellin Space Approach to Cosmological Correlators,JHEP01(2020) 090 [1906.12302]

    C. Sleight,A Mellin Space Approach to Cosmological Correlators,JHEP01(2020) 090 [1906.12302]. 54

    work page arXiv 2020

  71. [71]

    Sleight and M

    C. Sleight and M. Taronna,Bootstrapping Inflationary Correlators in Mellin Space,JHEP 02(2020) 098 [1907.01143]

    work page arXiv 2020

  72. [72]

    Sleight and M

    C. Sleight and M. Taronna,From AdS to dS exchanges: Spectral representation, Mellin amplitudes, and crossing,Phys. Rev. D104(2021) L081902 [2007.09993]

    work page arXiv 2021

  73. [73]

    Sleight and M

    C. Sleight and M. Taronna,From dS to AdS and back,JHEP12(2021) 074 [2109.02725]

    work page arXiv 2021

  74. [74]

    Premkumar,Regulating loops in de Sitter spacetime,Phys

    A. Premkumar,Regulating loops in de Sitter spacetime,Phys. Rev. D109(2024) 045003 [2110.12504]

    work page arXiv 2024

  75. [75]

    Qin,Cosmological correlators at the loop level,JHEP03(2025) 051 [2411.13636]

    Z. Qin,Cosmological correlators at the loop level,JHEP03(2025) 051 [2411.13636]

    work page arXiv 2025

  76. [76]

    H. Liu, Z. Qin and Z.-Z. Xianyu,Dispersive bootstrap of massive inflation correlators, JHEP02(2025) 101 [2407.12299]

    work page arXiv 2025

  77. [77]

    Chowdhury, S

    C. Chowdhury, S. Jazayeri, A. Lipstein, J. Marshall, J. Mei and I. Sachs,Cosmological Correlator Discontinuities from Scattering Amplitudes,2602.03841

    work page arXiv

  78. [78]

    S. Das, D. Karan, B. Khatun and N. Kundu,Reconstructing cosmological correlators via dispersion: from cutting to dressing rules,2602.05546

    work page arXiv

  79. [79]

    The IR stability of de Sitter: Loop corrections to scalar propagators

    D. Marolf and I.A. Morrison,The IR stability of de Sitter: Loop corrections to scalar propagators,Phys. Rev. D82(2010) 105032 [1006.0035]

    work page internal anchor Pith review Pith/arXiv arXiv 2010

  80. [80]

    Xianyu and H

    Z.-Z. Xianyu and H. Zhang,Bootstrapping one-loop inflation correlators with the spectral decomposition,JHEP04(2023) 103 [2211.03810]

    work page arXiv 2023

Showing first 80 references.