REVIEW 4 major objections 5 minor 3 cited by
The Exact and Approximate Tales of Boost-Breaking Cosmological Correlators
T0 review · 4 major / 5 minor · reviewed 2026-08-07 · deepseek-v4-flash
Pith's one-line read The paper derives the exact helical seed correlator for massive spinning exchange with a reduced sound speed and chemical potential, in bootstrap and spectral forms that match, converging in all kinematics and completing the…
desk verdict The combined cs+κ helical seed is a real step forward, but the paper needs a numerical check of the analytic continuation and an actual link to the code before I'd trust it as 'exact'. read the letter →
The pith
A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.
The reading
What carries the argument
The central object is the helical seed correlator $F^{(\lambda)}_{ab}$, a dimensionless Schwinger-Keldysh time integral built from Whittaker mode functions of a massive spinning field with chemical potential $\kappa$ and external legs of sound speed $c_s$. The bootstrap route solves a second-order boundary differential equation in the tilted kinematic variables $\tilde u = 2s/(c_s k_{12} + s)$ and $\tilde v = 2s/(c_s k_{34} + s)$; the load-bearing move is resumming one layer of the naive double series into a generalised hypergeometric function ${}_3F_2$, which continues the solution from $\tilde u < 1$ into the region $\tilde u > 1$ that $c_s < 1$ makes physically accessible. The spectral route replaces the time-ordered propagator by a contour integral over the mass parameter with a de Sitter density of states $N^{\lambda}_{\rho,\kappa} \propto \rho \sinh(2\pi\rho)\, \Gamma(\tfrac12 + i\lambda\kappa \mp i\rho)$; Cauchy's theorem then isolates particle-production poles at $\rho = \pm i\nu$ from EFT poles at $\rho = \pm i(n+\tfrac12)$, the latter summing the quasi-normal modes of the massive field. For the approximations, the machinery is a WKB expansion of the massive mode function followed by saddle-point evaluation of the factorised time integrals: the location of the saddle $\tau_\bullet$ in the complex time plane, and the arc angle $\theta_n$ needed to reach it around the origin or branch cut, determine both the waveform and the exponential amplitude factor $e^{-\theta_n \mu}$.
What would settle it
Evaluate the original Schwinger-Keldysh time integrals defining the seed (2.9) numerically, with a UV regulator and the $i\varepsilon$ prescription, in a configuration outside the unit circle — for instance $u = v = 5$, $c_s = 0.1$, $\mu = 3$, $\kappa = 1$ — and compare both real and imaginary parts against the bootstrap series (2.29) evaluated with the $\tilde u = \tilde u - i\varepsilon$ branch and against the spectral series (2.61)–(2.62): any disagreement beyond the tail of the series would show that the analytic continuation, and hence the physical status of the bootstrap solution in that regime, is wrong.
Extended reading notes
Core claim
The paper's central claim is that the helicity-labelled seed correlator $F^{(\lambda)}_{ab}$ — the building block out of which four-point correlators from tree-level exchange of a massive spinning field with chemical potential $\kappa$ and external legs of sound speed $c_s$ are assembled — is exactly given by a single partially resummed series made of five pieces: the factorised product of regularised hypergeometric functions (2.51), a boundary term (2.53) that enforces the correct late-time limit, the collider contributions picked out by particle-production poles of the spectral representation (2.59) together with its prefactor (2.56), and two EFT series (2.61) and (2.62) that sum over the quasi-normal modes of the massive field, the odd tower vanishing when $\kappa = 0$. The bootstrap solution and the spectral solution are claimed to match exactly in all kinematic configurations, including the region $u, v > 1$ opened up by $c_s < 1$ where the naive series diverges. On the approximate side, the paper claims that all non-analytic collider signals — local and non-local — are reproduced at leading order in the large-mass regime by evaluating the factorised bulk time integrals at saddle points of the complex time plane, with the Boltzmann suppression $e^{-\theta_n \mu}$ set by the arc angle $\theta_n = \pi/n$ the contour must travel, and that this yields the refined waveform $\cos[\mu\, \mathrm{arccosh}(k_S/k_L)]$ together with a transient signal $\cos[c_s \kappa\, k_L/k_S]$ in the presence of both boost-breaking parameters.
Load-bearing premise
The result rests on one analytic continuation: in kinematic regions where $c_s k_{12} < s$, the factorised and nested pieces of the bulk integral individually diverge, and the paper asserts that the physical correlator is the resummed series evaluated with a Cauchy principal-value prescription and the branch choice $\tilde u = \tilde u - i\varepsilon$; if that choice is not the true continuation of the Schwinger-Keldysh integral, the bootstrap answer in the small-sound-speed regime is not the physical correlator.
Editorial extensions
If this is right
- The tree-level catalogue of boost-breaking correlators is complete: every four-point exchange correlator with $\kappa \neq 0$ and $c_s < 1$ can be built from the seed by applying differential operators in the external momenta, with no further computation of bulk integrals.
- The refined waveform $\cos[\mu\, \mathrm{arccosh}(k_S/k_L)]$ stays accurate up to mildly soft and near-equilateral configurations, where the conventional $\cos[\mu \log(k_L/k_S)]$ template develops dephasing errors, giving survey analyses a template that is fast and correct where the signal-to-noise is largest.
- The amplitude formula $e^{-\pi\mu/2 - \mu \arcsin c_s}$, and its chemical-potential version $e^{-\pi(\mu-\kappa)/2}$, interpolates smoothly between the previously known de Sitter and strongly boost-breaking suppression factors, unifying them as arc angles of a single saddle.
- A transient signal oscillating linearly in $k_L/k_S$ with frequency $c_s \kappa$ appears in the edge region of kinematic space; because it is absent when either boost-breaking parameter vanishes, its detection would be a direct fingerprint of both.
- The bootstrap and spectral series provide a built-in cross-check on each other: the spectral representation carries the analytic continuation intrinsically, while the bootstrap converges faster inside the unit circle, so the two are complementary in practical evaluation.
Reading between the lines
- The paper's 'arc angle equals Boltzmann suppression' rule is demonstrated case by case; a natural extension would be to turn it into a general dictionary — the exponential strength of a collider signal as the residue of the bulk dispersion relation at early and late times — and to test it at one loop, where cutting rules already exist.
- Because the transient signal appears only when $\kappa \neq 0$ and $c_s < 1$ simultaneously, its observation would constrain two boost-breaking parameters at once; a promising testable target is the parity-odd sector of the trispectrum, where the paper itself shows the signal survives the factorisation constraints.
- The same saddle-point machinery could be applied to the scale-invariance-breaking models the paper lists as future work; one would predict that features in the background shift the saddles in the real-time direction, converting pure logarithmic oscillations into chirped, time-dependent waveforms — a concrete, checkable modification of the template.
- The most fragile link in the exact tale is the analytic-continuation prescription, so an independent route to the $c_s < 1$ correlator — for example a direct numerical Schwinger-Keldysh evaluation or a differently chosen ansatz with negative powers of $\tilde u$ — would either confirm the branch choice or expose a genuine subtlety in the bootstrap claim.
Editorial analysis
A structured set of objections, weighed in public.
Referee Report
Summary. The paper computes the tree-level four-point 'seed' correlator for the exchange of a massive, possibly spinning, helical particle, with external legs propagating at a reduced sound speed c_s. Two independent routes are presented: a bootstrap solution of the boundary differential equations (Sec. 2.2) and a spectral-representation evaluation (Sec. 2.3). Both are packaged as partially resummed single series claimed to converge in all physical kinematics, and the two representations are stated to match exactly. The second half of the paper develops a saddle-point/WKB approximation scheme for the time integrals, yielding elementary-function templates for local and non-local cosmological collider signals, including a boost-breaking bispectrum template. The paper also reports new phenomenological features, such as an interpolated Boltzmann suppression exp[-πμ/2 - μ arcsin(c_s)] and a 'transient' signal oscillating linearly in the momentum ratio with frequency c_s κ.
Significance. If the exactness claims hold, this completes the tree-level catalogue of boost-breaking cosmological correlators with non-unit sound speed and chemical potential, a genuinely useful result for the cosmological collider program. The paper's strengths are its two independent derivations, the careful discussion of convergence rates and evaluation times, and the concrete saddle-point picture that connects bulk production/decay times to boundary signal amplitudes. The proposed templates are falsifiable and ready for phenomenological use. The availability of a Mathematica notebook (modulo the placeholder link) is also a practical strength. The main unresolved issue is the analytic-continuation prescription for c_s < 1, which is asserted rather than proved; this is the load-bearing point on which the exactness claim rests.
major comments (4)
- [Sec. 2.2, Eq. (2.34)] The c_s < 1 analytic continuation is asserted rather than demonstrated. In the kinematic region c_s k_{12} < s, the factorised and nested pieces of the Schwinger-Keldysh integral individually diverge, as the paper itself notes after Eq. (2.33). The proposed remedy—resumming the tilde-u series and taking a Cauchy principal value with branch choice tilde{u} = tilde{u} - i epsilon—is stated to follow from the bulk integral, but no derivation is given that this prescription equals the i-epsilon-regulated defining integral (2.9). Since both the bootstrap result and the spectral result rely on analogous continuations, their mutual agreement does not by itself establish that the correct physical branch has been selected. I recommend adding a direct numerical evaluation of the regulated SK integral for representative c_s < 1 configurations and showing that the resummed series converges to it, or providing an analytic argument that the principal value and branch choice are exactly the continuation of (2.9).
- [Sec. 2.2 near Eq. (2.26) and Sec. 2.3 near Eq. (2.62)] The paper states that the result for tilde{u} > tilde{v} is obtained by swapping the variables, but for c_s < 1 this swap crosses a region where the series variables exceed unity and branch cuts are encountered. The text acknowledges that analytic continuation across kinematic regions can pick up homogeneous solutions, yet no explicit continuation rule is provided for the present case. This is directly relevant to the claim that the final series is valid in 'all physical kinematics'. Please specify the branch of the hypergeometric functions after the swap and verify continuity (or the expected discontinuity) across the surface u = v, e.g. by high-precision numerical checks on both sides.
- [Sec. 2.3, 'Full result'] The claimed exact equality between the bootstrap and spectral representations is supported only by the statement 'we have explicitly checked' and by plots for selected parameters. This is a central claim of the paper. The spectral derivation itself involves an analytic continuation in the mass parameter (ν → iμ) and a boundary term ΔG whose late-time oscillatory behaviour is handled by a continuation argument. I therefore ask for either a symbolic proof that the two representations are identical, or a systematic high-precision numerical comparison covering multiple values of μ, κ, λ, and both the interior and edge kinematic regions for c_s < 1, with an explicit error estimate in the main text.
- [Sec. 3.2.1, 'Discussion'] The authors acknowledge that the steepest-descent contour used for F_R^{(3),α} is not actually valid, because the contour is restricted by a branching point and contains points where the integrand exceeds the saddle height, and they state that a Wick-rotated contour 'eventually gives the same result' without showing it. Since the refined templates derived from this saddle-point analysis are a main deliverable, the remedy should be spelled out or the approximate formulas should be systematically benchmarked against the exact expressions over the full claimed validity range, not only for the few cases shown in Figs. 14 and 15.
minor comments (5)
- [Abstract and Sec. 2.2/2.3, Github references] The GitHub repository links appear as the literal placeholder '/github' rather than an actual URL; the paper cannot be reproduced until a working link is provided.
- [Figs. 3 and 4, captions] The captions state the series is truncated at n = 1, ..., N, but the displayed series (2.29), (2.61), and (2.62) start at n = 0. Please correct the caption or the summation limits.
- [Eq. (2.34) and surrounding text] The notation 'P.V.' is introduced pictorially but never defined in the text; please state explicitly which principal value is taken (e.g., symmetric cutoff around the singularity) and which variable is regulated.
- [Sec. 2.2 after Eq. (2.29)] The branch choice is described by the tautological phrase 'tilde u = tilde u - i epsilon'; this should be written as an explicit replacement, e.g. 'tilde u → tilde u - i epsilon', so that the direction of the i epsilon shift is unambiguous.
- [Sec. 3.3, bispectrum template (3.82)] The abstract promises a 'complete cosmological collider shape template capturing all boost-breaking effects', but the bispectrum template (3.82) contains no chemical potential, as the authors explain for the longitudinal mode. Please add a sentence in Sec. 3.3 clarifying that the complete boost-breaking template refers to the trispectrum, while the bispectrum template is limited to the longitudinal sector.
Circularity Check
No significant circularity: the exact correlator is solved from a sourced differential equation with independent boundary data and cross-checked by a separate spectral evaluation of the same Schwinger-Keldysh integral.
full rationale
The central exact result is not forced by its inputs by construction. The bootstrap route solves the sourced boundary differential equation (2.14) with an explicit ansatz (2.26), determines the homogeneous coefficients by matching an independently evaluated hierarchical soft limit (2.30), and resums the particular solution to obtain (2.29). The boundary data are not fitted to the final full-kinematics answer; they are an independent limit of the same integral, which is a standard and legitimate way to fix integration constants. The spectral route is a genuinely independent computation: it starts from the same SK seed integral (2.9), derives a spectral representation of the helical propagator in the insert around (2.42), and evaluates the resulting residues (2.51)-(2.62). The numerical agreement between the two representations is therefore a nontrivial cross-check, not a circular equivalence. The saddle-point templates in Sec. 3 are derived from WKB and saddle-point evaluation of factorised time integrals and are benchmarked against the exact expressions without fitting parameters. The main vulnerability identified by the skeptic is the analytic continuation for c_s < 1 via the branch choice tilde-u = tilde-u - i epsilon and the Cauchy principal-value prescription (2.34); even if this prescription were incorrect, it would be a correctness or branch-selection issue, not a circular reduction of the derivation to its own inputs. Self-citations to the authors' prior works [44,45,56] supply intermediate building blocks such as the homogeneous solutions and the spectral method, but these are published, parameter-free results and the paper also re-derives key spectral steps in an inserted derivation, so they do not function as unverified self-support.
Assumptions & free parameters
free parameters (1)
- Template phase constants delta_L, delta_NL, delta =
Not specified; examples use delta = 0 and delta = 3 pi / 4
assumptions (6)
- domain assumption Bunch-Davies initial conditions and a fixed quasi-de Sitter background.
- domain assumption All relevant boost-breaking physics is captured by the two-derivative action with parameters cs and chemical potential kappa.
- domain assumption The boundary coefficients A in Eq. (2.30) from prior work [44,45] are correct.
- domain assumption Analytic continuation in the de Sitter mass parameter from complementary series to heavy fields is valid.
- ad hoc to paper The Cauchy principal-value prescription and branch choice for cs < 1 reproduce the physical Schwinger-Keldysh integral.
- domain assumption The WKB/saddle-point approximation is valid for the regime µ >> 1 and kappa < mu.
Cite this review
Pith. "Pith review of The Exact and Approximate Tales of Boost-Breaking Cosmological Correlators." pith.science (2026). https://pith.science/paper/MX4LFFZP
@misc{pith2026250601555,
author = {Pith},
title = {Pith review of: The Exact and Approximate Tales of Boost-Breaking Cosmological Correlators},
year = {2026},
howpublished = {\url{https://pith.science/paper/MX4LFFZP}},
note = {Machine review of arXiv:2506.01555}
}
read the original abstract
Cosmological correlators offer a remarkable window into the high-energy physics governing Universe's earliest moments, with the tantalising prospect of discovering new particles. However, extracting new physics from these observables requires both precise theoretical predictions of inflationary theories and accurate, analytical templates suitable for data analysis throughout parameter and kinematic spaces. In this paper, we extend the current analytical results by computing the most general boost-breaking seed correlator mediated by the tree-level exchange of a massive spinning particle. We derive the result using two complementary approaches, bootstrapping from boundary differential equations, and direct spectral integration. Both representations are packaged as a single partially resummed series that converges in all physical kinematics. Computing this correlator marks a milestone for carving out the space of all boost-breaking correlators, and therefore completes the tree-level catalogue. We then introduce a general procedure to obtain accurate approximations for cosmological collider signals based on the saddle-point method. This approach allows for a clear physical intuition of various signals hidden in correlators, as the bulk physics is made manifest through the location of these saddles in the complex time plane, which depend on the external kinematics. Evaluating the time integrals at these saddles yields results given as elementary functions that remain valid beyond soft limits and provide intuitive control over both the signal shape and amplitude. We demonstrate the power of this method in both de Sitter-invariant and boost-breaking scenarios, and uncover novel refined waveform and strength dependence for oscillatory signals from massive fields. We provide a complete cosmological collider shape template capturing all boost-breaking effects for upcoming cosmological surveys.
Figures
Figures from the paper (12 more)
Forward citations
Cited by 3 Pith papers
-
Dissecting the Scalar Cosmological Collider with the Cosmic Microwave Background
A joint Bayesian fit of the multi-field inflationary Lagrangian to Planck bispectrum data finds no cosmological collider signal (max Δχ²=5.3) and shows weak-mixing template searches are invalid except at the smallest masses.
-
All Tree-Level Massive Cosmological Correlators via Spectral Gluing
Tree-level massive de Sitter correlators are constructed by gluing Lauricella-type vertex functions according to graph combinatorics, and the hypergeometric content collapses to rational functions once the dynamical p...
-
Amplifying the Cosmological Collider with Ghost Spectators
Ghost-condensate spectator fields exchanged during inflation cut the Boltzmann suppression of cosmological collider signals to e^{-πμ/2}, amplifying heavy-particle bispectrum and trispectrum imprints.
Reference graph
Works this paper leans on
-
[1]
P. D. Meerburget al., “Primordial Non-Gaussianity,”Bull. Am. Astron. Soc.51no. 3, (2019) 107, arXiv:1903.04409 [astro-ph.CO]
arXiv 2019
-
[2]
Inflation: Theory and Observations,
A. Ach´ ucarroet al., “Inflation: Theory and Observations,”arXiv:2203.08128 [astro-ph.CO]
-
[3]
Large non-Gaussianities with Intermediate Shapes from Quasi-Single Field Inflation,
X. Chen and Y. Wang, “Large non-Gaussianities with Intermediate Shapes from Quasi-Single Field Inflation,”Phys. Rev. D81(2010) 063511,arXiv:0909.0496 [astro-ph.CO]
arXiv 2010
-
[4]
Quasi-Single Field Inflation and Non-Gaussianities,
X. Chen and Y. Wang, “Quasi-Single Field Inflation and Non-Gaussianities,”JCAP04(2010) 027, arXiv:0911.3380 [hep-th]
arXiv 2010
-
[5]
Signatures of Supersymmetry from the Early Universe,
D. Baumann and D. Green, “Signatures of Supersymmetry from the Early Universe,”Phys. Rev. D 85(2012) 103520,arXiv:1109.0292 [hep-th]
arXiv 2012
-
[6]
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,arXiv:1211.1624 [hep-th]
arXiv 2013
-
[7]
Cosmological Collider Physics,
N. Arkani-Hamed and J. Maldacena, “Cosmological Collider Physics,”arXiv:1503.08043 [hep-th]
-
[8]
Equilateral non-Gaussianity from heavy fields,
J.-O. Gong, S. Pi, and M. Sasaki, “Equilateral non-Gaussianity from heavy fields,”JCAP11(2013) 043,arXiv:1306.3691 [hep-th]
arXiv 2013
Show all 92 references
-
[9]
Quantum Primordial Standard Clocks,
X. Chen, M. H. Namjoo, and Y. Wang, “Quantum Primordial Standard Clocks,”JCAP02(2016) 013,arXiv:1509.03930 [astro-ph.CO]
2016 arXiv
-
[10]
Standard Model Background of the Cosmological Collider,
X. Chen, Y. Wang, and Z.-Z. Xianyu, “Standard Model Background of the Cosmological Collider,” Phys. Rev. Lett.118no. 26, (2017) 261302,arXiv:1610.06597 [hep-th]
2017 arXiv
-
[11]
Non-Gaussianity as a Particle Detector,
H. Lee, D. Baumann, and G. L. Pimentel, “Non-Gaussianity as a Particle Detector,”JHEP12 (2016) 040,arXiv:1607.03735 [hep-th]
2016 arXiv
-
[12]
Quasi Single Field Inflation in the non-perturbative regime,
H. An, M. McAneny, A. K. Ridgway, and M. B. Wise, “Quasi Single Field Inflation in the non-perturbative regime,”JHEP06(2018) 105,arXiv:1706.09971 [hep-ph]
2018 arXiv
-
[13]
A Cosmological Higgs Collider,
S. Lu, Y. Wang, and Z.-Z. Xianyu, “A Cosmological Higgs Collider,”JHEP02(2020) 011, arXiv:1907.07390 [hep-th]
2020 arXiv
-
[14]
Searches for other vacua. Part II. A new Higgstory at the cosmological collider,
A. Hook, J. Huang, and D. Racco, “Searches for other vacua. Part II. A new Higgstory at the cosmological collider,”JHEP01(2020) 105,arXiv:1907.10624 [hep-ph]
2020 arXiv
-
[15]
Probing P and CP Violations on the Cosmological Collider,
T. Liu, X. Tong, Y. Wang, and Z.-Z. Xianyu, “Probing P and CP Violations on the Cosmological Collider,”JHEP04(2020) 189,arXiv:1909.01819 [hep-ph]
2020 arXiv
-
[16]
Cosmological Collider Physics and the Curvaton,
S. Kumar and R. Sundrum, “Cosmological Collider Physics and the Curvaton,”JHEP04(2020) 077,arXiv:1908.11378 [hep-ph]
2020 arXiv
-
[17]
In Search of Large Signals at the Cosmological Collider,
L.-T. Wang and Z.-Z. Xianyu, “In Search of Large Signals at the Cosmological Collider,”JHEP02 (2020) 044,arXiv:1910.12876 [hep-ph]
2020 arXiv
-
[18]
Gauge Boson Signals at the Cosmological Collider,
L.-T. Wang and Z.-Z. Xianyu, “Gauge Boson Signals at the Cosmological Collider,”JHEP11 (2020) 082,arXiv:2004.02887 [hep-ph]
2020 arXiv
-
[19]
Cosmological Collider Signatures of Massive Vectors from Non-Gaussian Gravitational Waves,
Y. Wang and Y. Zhu, “Cosmological Collider Signatures of Massive Vectors from Non-Gaussian Gravitational Waves,”JCAP04(2020) 049,arXiv:2001.03879 [astro-ph.CO]
2020 arXiv
-
[20]
Inflationary flavor oscillations and the cosmic spectroscopy,
L. Pinol, S. Aoki, S. Renaux-Petel, and M. Yamaguchi, “Inflationary flavor oscillations and the cosmic spectroscopy,”Phys. Rev. D107no. 2, (2023) L021301,arXiv:2112.05710 [hep-th]. 64
2023 arXiv
-
[21]
Probing Leptogenesis with the Cosmological Collider,
Y. Cui and Z.-Z. Xianyu, “Probing Leptogenesis with the Cosmological Collider,”Phys. Rev. Lett. 129no. 11, (2022) 111301,arXiv:2112.10793 [hep-ph]
2022 arXiv
-
[22]
Large-field inflation and the cosmological collider,
M. Reece, L.-T. Wang, and Z.-Z. Xianyu, “Large-field inflation and the cosmological collider,”Phys. Rev. D107no. 10, (2023) L101304,arXiv:2204.11869 [hep-ph]
2023 arXiv
-
[23]
Classical cosmological collider physics and primordial features,
X. Chen, R. Ebadi, and S. Kumar, “Classical cosmological collider physics and primordial features,” JCAP08(2022) 083,arXiv:2205.01107 [hep-ph]
2022 arXiv
-
[24]
Phase information in cosmological collider signals,
Z. Qin and Z.-Z. Xianyu, “Phase information in cosmological collider signals,”JHEP10(2022) 192, arXiv:2205.01692 [hep-th]
2022 arXiv
-
[25]
Cosmological Flow of Primordial Correlators,
D. Werth, L. Pinol, and S. Renaux-Petel, “Cosmological Flow of Primordial Correlators,”Phys. Rev. Lett.133no. 14, (2024) 141002,arXiv:2302.00655 [hep-th]
2024 arXiv
-
[26]
Shapes of the cosmological low-speed collider,
S. Jazayeri, S. Renaux-Petel, and D. Werth, “Shapes of the cosmological low-speed collider,”JCAP 12(2023) 035,arXiv:2307.01751 [hep-th]
2023 arXiv
-
[27]
Parity Violation from Emergent Non-Locality During Inflation,
S. Jazayeri, S. Renaux-Petel, X. Tong, D. Werth, and Y. Zhu, “Parity Violation from Emergent Non-Locality During Inflation,”arXiv:2308.11315 [hep-th]
-
[28]
The cosmological flow: a systematic approach to primordial correlators,
L. Pinol, S. Renaux-Petel, and D. Werth, “The cosmological flow: a systematic approach to primordial correlators,”JCAP02(2025) 019,arXiv:2312.06559 [astro-ph.CO]
2025 arXiv
-
[29]
Cosmological collider signatures of Higgs-R 2 inflation,
Y. Ema and S. Verner, “Cosmological collider signatures of Higgs-R 2 inflation,”JCAP04(2024) 039,arXiv:2309.10841 [hep-ph]
2024 arXiv
-
[30]
BCS in the sky: signatures of inflationary fermion condensation,
X. Tong, Y. Wang, C. Zhang, and Y. Zhu, “BCS in the sky: signatures of inflationary fermion condensation,”JCAP04(2024) 022,arXiv:2304.09428 [hep-th]
2024 arXiv
-
[31]
Compact scalars at the cosmological collider,
P. Chakraborty and J. Stout, “Compact scalars at the cosmological collider,”JHEP03(2024) 149, arXiv:2311.09219 [hep-th]
2024 arXiv
-
[32]
CosmoFlow: Python Package for Cosmological Correlators,
D. Werth, L. Pinol, and S. Renaux-Petel, “CosmoFlow: Python Package for Cosmological Correlators,”Class. Quant. Grav.41no. 17, (2024) 175015,arXiv:2402.03693 [astro-ph.CO]
2024 arXiv
-
[33]
Cosmological collider non-Gaussianity from multiple scalars and R2 gravity,
S. Aoki, A. Ghoshal, and A. Strumia, “Cosmological collider non-Gaussianity from multiple scalars and R2 gravity,”JHEP11(2024) 009,arXiv:2408.07069 [astro-ph.CO]
2024 arXiv
-
[34]
The cosmological collider in R 2 inflation,
Y.-P. Wu, “The cosmological collider in R 2 inflation,”JCAP07(2024) 010,arXiv:2404.05031 [astro-ph.CO]
2024 arXiv
-
[35]
An effective cosmological collider,
N. Craig, S. Kumar, and A. McCune, “An effective cosmological collider,”JHEP07(2024) 108, arXiv:2401.10976 [hep-ph]
2024 arXiv
-
[36]
A cosmological tachyon collider: enhancing the long-short scale coupling,
C. McCulloch, E. Pajer, and X. Tong, “A cosmological tachyon collider: enhancing the long-short scale coupling,”JHEP05(2024) 262,arXiv:2401.11009 [hep-th]
2024 arXiv
-
[37]
BOSS constraints on massive particles during inflation: The cosmological collider in action,
G. Cabass, O. H. E. Philcox, M. M. Ivanov, K. Akitsu, S.-F. Chen, M. Simonovi´ c, and M. Zaldarriaga, “BOSS constraints on massive particles during inflation: The cosmological collider in action,”Phys. Rev. D111no. 6, (2025) 063510,arXiv:2404.01894 [astro-ph.CO]
2025 arXiv
-
[38]
Searching for cosmological collider in the Planck CMB data,
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,arXiv:2404.07203 [astro-ph.CO]
2024 arXiv
-
[39]
The UV Sensitivity of Axion Monodromy Inflation,
E. Pajer, D.-G. Wang, and B. Zhang, “The UV Sensitivity of Axion Monodromy Inflation,” arXiv:2412.05762 [hep-th]. 65
-
[40]
Bootstrapping the Cosmological Collider with Resonant Features,
D.-G. Wang and B. Zhang, “Bootstrapping the Cosmological Collider with Resonant Features,” arXiv:2505.19066 [hep-th]
-
[41]
The Cosmological Bootstrap: Inflationary Correlators from Symmetries and Singularities,
N. Arkani-Hamed, D. Baumann, H. Lee, and G. L. Pimentel, “The Cosmological Bootstrap: Inflationary Correlators from Symmetries and Singularities,”JHEP04(2020) 105, arXiv:1811.00024 [hep-th]
2020 arXiv
-
[42]
Boostless cosmological collider bootstrap,
G. L. Pimentel and D.-G. Wang, “Boostless cosmological collider bootstrap,”JHEP10(2022) 177, arXiv:2205.00013 [hep-th]
2022 arXiv
-
[43]
Cosmological bootstrap in slow motion,
S. Jazayeri and S. Renaux-Petel, “Cosmological bootstrap in slow motion,”JHEP12(2022) 137, arXiv:2205.10340 [hep-th]
2022 arXiv
-
[44]
Helical inflation correlators: partial Mellin-Barnes and bootstrap equations,
Z. Qin and Z.-Z. Xianyu, “Helical inflation correlators: partial Mellin-Barnes and bootstrap equations,”JHEP04(2023) 059,arXiv:2208.13790 [hep-th]
2023 arXiv
-
[45]
Closed-form formulae for inflation correlators,
Z. Qin and Z.-Z. Xianyu, “Closed-form formulae for inflation correlators,”JHEP07(2023) 001, arXiv:2301.07047 [hep-th]
2023 arXiv
-
[46]
Cosmological correlators with double massive exchanges: bootstrap equation and phenomenology,
S. Aoki, L. Pinol, F. Sano, M. Yamaguchi, and Y. Zhu, “Cosmological correlators with double massive exchanges: bootstrap equation and phenomenology,”JHEP09(2024) 176, arXiv:2404.09547 [hep-th]
2024 arXiv
-
[47]
Massive Inflationary Amplitudes: Differential Equations and Complete Solutions for General Trees,
H. Liu and Z.-Z. Xianyu, “Massive Inflationary Amplitudes: Differential Equations and Complete Solutions for General Trees,”arXiv:2412.07843 [hep-th]
-
[48]
Multivariate hypergeometric solutions of cosmological (dS) correlators by d log-form differential equations,
J. Chen, B. Feng, and Y.-X. Tao, “Multivariate hypergeometric solutions of cosmological (dS) correlators by d log-form differential equations,”JHEP03(2025) 075,arXiv:2411.03088 [hep-th]
2025 arXiv
-
[49]
A Mellin Space Approach to Cosmological Correlators,
C. Sleight, “A Mellin Space Approach to Cosmological Correlators,”JHEP01(2020) 090, arXiv:1906.12302 [hep-th]
2020 arXiv
-
[50]
Bootstrapping Inflationary Correlators in Mellin Space,
C. Sleight and M. Taronna, “Bootstrapping Inflationary Correlators in Mellin Space,”JHEP02 (2020) 098,arXiv:1907.01143 [hep-th]
2020 arXiv
-
[51]
Inflation correlators at the one-loop order: nonanalyticity, factorization, cutting rule, and OPE,
Z. Qin and Z.-Z. Xianyu, “Inflation correlators at the one-loop order: nonanalyticity, factorization, cutting rule, and OPE,”JHEP09(2023) 116,arXiv:2304.13295 [hep-th]
2023 arXiv
-
[52]
Nonanalyticity and on-shell factorization of inflation correlators at all loop orders,
Z. Qin and Z.-Z. Xianyu, “Nonanalyticity and on-shell factorization of inflation correlators at all loop orders,”JHEP01(2024) 168,arXiv:2308.14802 [hep-th]
2024 arXiv
-
[53]
Inflation correlators with multiple massive exchanges,
Z.-Z. Xianyu and J. Zang, “Inflation correlators with multiple massive exchanges,”JHEP03(2024) 070,arXiv:2309.10849 [hep-th]
2024 arXiv
-
[54]
Cosmological correlators at the loop level,
Z. Qin, “Cosmological correlators at the loop level,”JHEP03(2025) 051,arXiv:2411.13636 [hep-th]
2025 arXiv
-
[55]
Bootstrapping one-loop inflation correlators with the spectral decomposition,
Z.-Z. Xianyu and H. Zhang, “Bootstrapping one-loop inflation correlators with the spectral decomposition,”JHEP04(2023) 103,arXiv:2211.03810 [hep-th]
2023 arXiv
-
[56]
Spectral representation of cosmological correlators,
D. Werth, “Spectral representation of cosmological correlators,”JHEP12(2024) 017, arXiv:2409.02072 [hep-th]
2024 arXiv
-
[57]
Dispersive bootstrap of massive inflation correlators,
H. Liu, Z. Qin, and Z.-Z. Xianyu, “Dispersive bootstrap of massive inflation correlators,”JHEP02 (2025) 101,arXiv:2407.12299 [hep-th]
2025 arXiv
-
[58]
On graviton non-Gaussianities during inflation,
J. M. Maldacena and G. L. Pimentel, “On graviton non-Gaussianities during inflation,”JHEP09 (2011) 045,arXiv:1104.2846 [hep-th]. 66
2011 arXiv
-
[59]
Conformal invariance of scalar perturbations in inflation,
P. Creminelli, “Conformal invariance of scalar perturbations in inflation,”Phys. Rev. D85(2012) 041302,arXiv:1108.0874 [hep-th]
2012 arXiv
-
[60]
Operator Product Expansion of Inflationary Correlators and Conformal Symmetry of de Sitter,
A. Kehagias and A. Riotto, “Operator Product Expansion of Inflationary Correlators and Conformal Symmetry of de Sitter,”Nucl. Phys. B864(2012) 492–529,arXiv:1205.1523 [hep-th]
2012 arXiv
-
[61]
CMB from CFT,
I. Mata, S. Raju, and S. Trivedi, “CMB from CFT,”JHEP07(2013) 015,arXiv:1211.5482 [hep-th]
2013 arXiv
-
[62]
Conformal Invariance and the Four Point Scalar Correlator in Slow-Roll Inflation,
A. Ghosh, N. Kundu, S. Raju, and S. P. Trivedi, “Conformal Invariance and the Four Point Scalar Correlator in Slow-Roll Inflation,”JHEP07(2014) 011,arXiv:1401.1426 [hep-th]
2014 arXiv
-
[63]
Constraints from Conformal Symmetry on the Three Point Scalar Correlator in Inflation,
N. Kundu, A. Shukla, and S. P. Trivedi, “Constraints from Conformal Symmetry on the Three Point Scalar Correlator in Inflation,”JHEP04(2015) 061,arXiv:1410.2606 [hep-th]
2015 arXiv
-
[64]
Non-Gaussian features of primordial fluctuations in single field inflationary models,
J. M. Maldacena, “Non-Gaussian features of primordial fluctuations in single field inflationary models,”JHEP05(2003) 013,arXiv:astro-ph/0210603
2003 arXiv
-
[65]
DBI in the sky,
M. Alishahiha, E. Silverstein, and D. Tong, “DBI in the sky,”Phys. Rev. D70(2004) 123505, arXiv:hep-th/0404084
2004 arXiv
-
[66]
Observational signatures and non-Gaussianities of general single field inflation,
X. Chen, M.-x. Huang, S. Kachru, and G. Shiu, “Observational signatures and non-Gaussianities of general single field inflation,”JCAP01(2007) 002,arXiv:hep-th/0605045
2007 arXiv
-
[67]
The Effective Field Theory of Inflation,
C. Cheung, P. Creminelli, A. L. Fitzpatrick, J. Kaplan, and L. Senatore, “The Effective Field Theory of Inflation,”JHEP03(2008) 014,arXiv:0709.0293 [hep-th]
2008 arXiv
-
[68]
Chemical-potential-assisted particle production in FR W spacetimes,
C. M. Sou, X. Tong, and Y. Wang, “Chemical-potential-assisted particle production in FR W spacetimes,”JHEP06(2021) 129,arXiv:2104.08772 [hep-th]
2021 arXiv
-
[69]
Fermion production during and after axion inflation,
P. Adshead and E. I. Sfakianakis, “Fermion production during and after axion inflation,”JCAP11 (2015) 021,arXiv:1508.00891 [hep-ph]
2015 arXiv
-
[70]
Imprints of Schwinger Effect on Primordial Spectra,
W. Z. Chua, Q. Ding, Y. Wang, and S. Zhou, “Imprints of Schwinger Effect on Primordial Spectra,” JHEP04(2019) 066,arXiv:1810.09815 [hep-th]
2019 arXiv
-
[71]
Large spin-2 signals at the cosmological collider,
X. Tong and Z.-Z. Xianyu, “Large spin-2 signals at the cosmological collider,”JHEP10(2022) 194, arXiv:2203.06349 [hep-ph]
2022 arXiv
-
[72]
The Scalar Chemical Potential in Cosmological Collider Physics,
A. Bodas, S. Kumar, and R. Sundrum, “The Scalar Chemical Potential in Cosmological Collider Physics,”JHEP02(2021) 079,arXiv:2010.04727 [hep-ph]
2021 arXiv
-
[73]
Grand unification at the cosmological collider with chemical potential,
A. Bodas, E. Broadberry, and R. Sundrum, “Grand unification at the cosmological collider with chemical potential,”JHEP01(2025) 115,arXiv:2409.07524 [hep-ph]
2025 arXiv
-
[74]
Neutrino Signatures in Primordial Non-Gaussianities,
X. Chen, Y. Wang, and Z.-Z. Xianyu, “Neutrino Signatures in Primordial Non-Gaussianities,” JHEP09(2018) 022,arXiv:1805.02656 [hep-ph]
2018 arXiv
-
[75]
New inflationary probes of axion dark matter,
X. Chen, J. Fan, and L. Li, “New inflationary probes of axion dark matter,”JHEP12(2023) 197, arXiv:2303.03406 [hep-ph]
2023 arXiv
-
[76]
Primordial Stochastic Gravitational Waves from Massive Higher-Spin Bosons,
H. An, Z. Qin, Z.-Z. Xianyu, and B. Zhang, “Primordial Stochastic Gravitational Waves from Massive Higher-Spin Bosons,”arXiv:2504.05389 [hep-ph]
-
[77]
Cosmological correlators through the looking glass: reality, parity, and factorisation,
D. Stefanyszyn, X. Tong, and Y. Zhu, “Cosmological correlators through the looking glass: reality, parity, and factorisation,”JHEP05(2024) 196,arXiv:2309.07769 [hep-th]
2024 arXiv
-
[78]
Light Particles with Spin in Inflation,
L. Bordin, P. Creminelli, A. Khmelnitsky, and L. Senatore, “Light Particles with Spin in Inflation,” JCAP10(2018) 013,arXiv:1806.10587 [hep-th]. 67
2018 arXiv
-
[79]
Schwinger-Keldysh Diagrammatics for Primordial Perturbations,
X. Chen, Y. Wang, and Z.-Z. Xianyu, “Schwinger-Keldysh Diagrammatics for Primordial Perturbations,”JCAP12(2017) 006,arXiv:1703.10166 [hep-th]
2017 arXiv
-
[80]
Cutting rule for cosmological collider signals: a bulk evolution perspective,
X. Tong, Y. Wang, and Y. Zhu, “Cutting rule for cosmological collider signals: a bulk evolution perspective,”JHEP03(2022) 181,arXiv:2112.03448 [hep-th]
2022 arXiv
-
[81]
Cutting rule for in-in correlators and cosmological collider,
Y. Ema and K. Mukaida, “Cutting rule for in-in correlators and cosmological collider,”JHEP12 (2024) 194,arXiv:2409.07521 [hep-th]
2024 arXiv
-
[82]
There and Back Again: Mapping and Factorizing Cosmological Observables,
D. Stefanyszyn, X. Tong, and Y. Zhu, “There and Back Again: Mapping and Factorizing Cosmological Observables,”Phys. Rev. Lett.133no. 22, (2024) 221501,arXiv:2406.00099 [hep-th]
2024 arXiv
-
[83]
A Match Made in Heaven: Linking Observables in Inflationary Cosmology,
D. Stefanyszyn, X. Tong, and Y. Zhu, “A Match Made in Heaven: Linking Observables in Inflationary Cosmology,”arXiv:2505.16071 [hep-th]
-
[84]
Late-time Structure of the Bunch-Davies De Sitter Wavefunction,
D. Anninos, T. Anous, D. Z. Freedman, and G. Konstantinidis, “Late-time Structure of the Bunch-Davies De Sitter Wavefunction,”JCAP11(2015) 048,arXiv:1406.5490 [hep-th]
2015 arXiv
-
[85]
Shapes of gravity: Tensor non-Gaussianity and massive spin-2 fields,
G. Goon, K. Hinterbichler, A. Joyce, and M. Trodden, “Shapes of gravity: Tensor non-Gaussianity and massive spin-2 fields,”JHEP10(2019) 182,arXiv:1812.07571 [hep-th]
2019 arXiv
-
[86]
On the integration of products of whittaker functions with respect to the second index,
P. A. Becker, “On the integration of products of whittaker functions with respect to the second index,”Journal of Mathematical Physics45no. 2, (02, 2004) 761–773, https://pubs.aip.org/aip/jmp/article-pdf/45/2/761/19194621/761 1 online.pdf. https://doi.org/10.1063/1.1634351
2004 doi
-
[87]
NIST Digital Library of Mathematical Functions
“NIST Digital Library of Mathematical Functions.”https://dlmf.nist.gov/, release 1.2.2 of 2024-09-15.https://dlmf.nist.gov/. F. W. J. Olver, A. B. Olde Daalhuis, D. W. Lozier, B. I. Schneider, R. F. Boisvert, C. W. Clark, B. R. Miller, B. V. Saunders, H. S. Cohl, and M. A. McC...
2024
-
[88]
Uniform Asymptotic Smoothing of Stokes’s Discontinuities,
M. V. Berry, “Uniform Asymptotic Smoothing of Stokes’s Discontinuities,”Proceedings of the Royal Society of London Series A422no. 1862, (Mar., 1989) 7–21
1989
-
[89]
Gravitational Production of Superheavy Dark Matter and Associated Cosmological Signatures,
L. Li, T. Nakama, C. M. Sou, Y. Wang, and S. Zhou, “Gravitational Production of Superheavy Dark Matter and Associated Cosmological Signatures,”JHEP07(2019) 067,arXiv:1903.08842 [astro-ph.CO]
2019 arXiv
-
[90]
Donaldson,Riemann Surfaces
S. Donaldson,Riemann Surfaces. 03, 2011
2011
-
[91]
Bruijn, de,Asymptotic methods in analysis
N. Bruijn, de,Asymptotic methods in analysis. Bibliotheca Mathematica. Noordhoff, 1st ed., 1958
1958
-
[92]
C. M. Bender and S. A. Orszag,Advanced Mathematical Methods for Scientists and Engineers. McGraw-Hill, 1978. 68
1978
Reviewed August 7, 2026 · model on record in the stance chip above.
Discussion (0). Sign in to comment.