Modularity of higher theta series I: cohomology of the generic fiber
Publications Mathématiques de l'IHÉS, Online first, pp. 1-161

In a previous paper we constructed higher theta series for unitary groups over function fields, and conjectured their modularity properties. Here we prove the generic modularity of the $\ell $-adic realization of higher theta series in cohomology. The proof debuts a new type of Fourier transform, occurring on the Borel–Moore homology of moduli spaces for shtuka-type objects, that we call the arithmetic Fourier transform. Another novelty in the argument is a sheaf-cycle correspondence extending the classical sheaf-function correspondence, which facilitates the deployment of sheaf-theoretic methods to analyze algebraic cycles. Although the modularity property is a statement within classical algebraic geometry, the proof relies on derived algebraic geometry, especially a nascent theory of derived Fourier analysis on derived vector bundles, which we develop.

Received:
Accepted:
Online First:
DOI: 10.5802/pmihes.27

Tony Feng  1 ; Zhiwei Yun  2 ; Wei Zhang  2

1 University of California Berkeley Department of Mathematics Berkeley, CA 94720, USA
2 Massachusetts Institute of Technology Department of Mathematics 77 Massachusetts Avenue Cambridge, MA 02139, USA
Tony Feng; Zhiwei Yun; Wei Zhang. Modularity of higher theta series I: cohomology of the generic fiber. Publications Mathématiques de l'IHÉS, Online first, pp. 1-161
@unpublished{10_5802_pmihes_27,
     author = {Tony Feng and Zhiwei Yun and Wei Zhang},
     title = {Modularity of higher theta series {I:} cohomology of the generic fiber},
     journal = {Publications Math\'ematiques de l'IH\'ES},
     year = {2026},
     publisher = {IHES},
     doi = {10.5802/pmihes.27},
     language = {en},
     note = {Online first},
}
TY  - UNPB
AU  - Tony Feng
AU  - Zhiwei Yun
AU  - Wei Zhang
TI  - Modularity of higher theta series I: cohomology of the generic fiber
JO  - Publications Mathématiques de l'IHÉS
PY  - 2026
PB  - IHES
N1  - Online first
DO  - 10.5802/pmihes.27
LA  - en
ID  - 10_5802_pmihes_27
ER  - 
%0 Unpublished Work
%A Tony Feng
%A Zhiwei Yun
%A Wei Zhang
%T Modularity of higher theta series I: cohomology of the generic fiber
%J Publications Mathématiques de l'IHÉS
%D 2026
%V 0
%I IHES
%Z Online first
%R 10.5802/pmihes.27
%G en
%F 10_5802_pmihes_27

[1] Richard E. Borcherds The Gross–Kohnen–Zagier theorem in higher dimensions, Duke Math. J., Volume 97 (1999) no. 2, pp. 219-233 | DOI | MR | Zbl

[2] Jan H. Bruinier; Benjamin Howard; Stephen S. Kudla; Michael Rapoport; Tonghai Yang Modularity of generating series of divisors on unitary Shimura varieties, Diviseurs arithmétiques sur les variétés orthogonales et unitaires de Shimura (Astérisque), Volume 421, Société Mathématique de France, 2020, pp. 7-125 | MR

[3] Jan H. Bruinier; Martin Westerholt-Raum Kudla’s modularity conjecture and formal Fourier–Jacobi series, Forum Math. Pi, Volume 3 (2015), e7, 30 pages | DOI | MR | Zbl

[4] Vladimir Drinfeld; Dennis Gaitsgory Compact generation of the category of D-modules on the stack of ${G}$-bundles on a curve, Camb. J. Math., Volume 3 (2015) no. 1-2, pp. 19-125 | DOI | MR | Zbl

[5] Harold M. Edwards Riemann’s zeta function. Unabridged reprint of the 1974 original, Dover Publications, 2001, xiv+315 pages | MR | Zbl

[6] Tony Feng; Adeel A. Khan Modularity of higher theta series II: Chow group of the generic fiber (2024) | arXiv | Zbl

[7] Tony Feng; Jonathan Wang Geometric Langlands duality for periods, Geom. Funct. Anal., Volume 35 (2025) no. 2, pp. 463-541 | DOI | MR | Zbl

[8] Tony Feng; Zhiwei Yun; Wei Zhang Higher Siegel–Weil formula for unitary groups: the non-singular terms, Invent. Math., Volume 235 (2024) no. 2, pp. 569-668 | DOI | MR | Zbl

[9] Tony Feng; Zhiwei Yun; Wei Zhang Higher theta series for unitary groups over function fields, Ann. Sci. Éc. Norm. Supér. (4), Volume 58 (2025) no. 2, pp. 275-388 | DOI | MR | Zbl

[10] Dennis Gaitsgory; Yakov Varshavsky Local terms for the categorical trace, Adv. Math., Volume 470 (2025), 110223, 67 pages | DOI | MR | Zbl

[11] Cohomologie $l$-adique et fonctions ${L}$. Séminaire de Géometrie Algébrique du Bois-Marie 1965–1966 (SGA 5) (Alexander Grothendieck, ed.), Lecture Notes in Mathematics, 589, Springer, 1977, xii+484 pages | MR | Zbl | Numdam

[12] Friedrich Hirzebruch; Don Zagier Intersection numbers of curves on Hilbert modular surfaces and modular forms of Nebentypus, Invent. Math., Volume 36 (1976), pp. 57-113 | DOI | MR | Zbl

[13] Benjamin Howard; Keerthi Madapusi Kudla’s modularity conjecture on integral models of orthogonal Shimura varieties, Compos. Math., Volume 161 (2025) no. 12, pp. 3380-3454 | DOI | Zbl | MR

[14] Benjamin Howard; Keerthi Madapusi Pera Arithmetic of Borcherds products, Diviseurs arithmétiques sur les variétés orthogonales et unitaires de Shimura (Astérisque), Société Mathématique de France, 2020 no. 421, pp. 187-297 | MR

[15] Carl G. J. Jacobi Suite des notices sur les fonctions elliptiques, J. Reine Angew. Math., Volume 3 (1828), pp. 403-404 | DOI | MR | Zbl

[16] Adeel A. Khan Virtual fundamental classes of derived stacks I (2019) | arXiv | Zbl

[17] Stephen S. Kudla Special cycles and derivatives of Eisenstein series, Heegner points and Rankin ${L}$-series (Mathematical Sciences Research Institute Publications), Volume 49, Cambridge University Press, 2004, pp. 243-270 | DOI | MR | Zbl

[18] Stephen S. Kudla Remarks on generating series for special cycles on orthogonal Shimura varieties, Algebra Number Theory, Volume 15 (2021) no. 10, pp. 2403-2447 | DOI | MR | Zbl

[19] Stephen S. Kudla; John J. Millson Intersection numbers of cycles on locally symmetric spaces and Fourier coefficients of holomorphic modular forms in several complex variables, Publ. Math., Inst. Hautes Étud. Sci., Volume 71 (1990), pp. 121-172 | MR | Zbl | Numdam | DOI

[20] Gérard Laumon Transformation de Fourier, constantes d’équations fonctionnelles et conjecture de Weil, Publ. Math., Inst. Hautes Étud. Sci., Volume 65 (1987), pp. 131-210 | MR | Zbl | Numdam | DOI

[21] Yifeng Liu; Weizhe Zheng Enhanced adic formalism and perverse t-structures for higher Artin stacks (2017) | arXiv | Zbl

[22] Yifeng Liu; Weizhe Zheng Enhanced six operations and base change theorem for higher Artin stacks (2017) | arXiv | Zbl

[23] Qing Lu; Weizhe Zheng Categorical traces and a relative Lefschetz–Verdier formula, Forum Math. Sigma, Volume 10 (2022), e10, 24 pages | DOI | MR | Zbl

[24] Jacob Lurie Spectral Algebraic Geometry, 2019 https://www.math.ias.edu/...

[25] Keerthi Madapusi Derived special cycles on Shimura varieties (2023) | arXiv | Zbl

[26] Martin Olsson Borel–Moore homology, Riemann–Roch transformations, and local terms, Adv. Math., Volume 273 (2015), pp. 56-123 | DOI | MR | Zbl

[27] Ananth N. Shankar; Arul Shankar; Yunqing Tang; Salim Tayou Exceptional jumps of Picard ranks of reductions of K3 surfaces over number fields, Forum Math. Pi, Volume 10 (2022), e21, 49 pages | DOI | MR | Zbl

[28] Bertrand Toen Champs affines, Sel. Math., New Ser., Volume 12 (2006) no. 1, pp. 39-135 | DOI | MR | Zbl

[29] Bertrand Toen Derived algebraic geometry, EMS Surv. Math. Sci., Volume 1 (2014) no. 2, pp. 153-240 | DOI | MR | Zbl

[30] Bertrand Toën; Gabriele Vezzosi Homotopical algebraic geometry. II. Geometric stacks and applications, Memoirs of the American Mathematical Society, 902, American Mathematical Society, 2008, x+224 pages | DOI | MR | Zbl

[31] Yakov Varshavsky Lefschetz–Verdier trace formula and a generalization of a theorem of Fujiwara, Geom. Funct. Anal., Volume 17 (2007) no. 1, pp. 271-319 | DOI | MR | Zbl

[32] Jean-Louis Verdier A duality theorem in the etale cohomology of schemes, Proceedings of a conference on local fields. NUFFIC Summer School (Driebergen, 1966), Springer (1967), pp. 184-198 | MR | Zbl | DOI

[33] André Weil Sur certains groupes d’opérateurs unitaires, Acta Math., Volume 111 (1964), pp. 143-211 | DOI | MR | Zbl

[34] Zhiwei Yun; Wei Zhang Shtukas and the Taylor expansion of ${L}$-functions, Ann. Math. (2), Volume 186 (2017) no. 3, pp. 767-911 | DOI | MR | Zbl

[35] W. Zhang Weil representation and arithmetic fundamental lemma, Ann. Math. (2), Volume 193 (2021) no. 3, pp. 863-978 | DOI | MR | Zbl

[36] Wei Zhang Modularity of generating functions of special cycles on Shimura varieties, Ph. D. Thesis, Columbia University, USA (2009)

Cited by Sources: