Research activity information

• Jul. 2022 神戸大学, 前之園記念若手優秀論文賞


• Sep. 2015 The Mathematical Society of Japan, Takebe Katahiro Prize for Encouragement of Young Researchers


• Mar. 2015 Inoue Foundation for Science, Inoue Research Award for Young Scientists

• Model transition for certain Langlands quotients of GL _{4 n}

  Kazuki Morimoto

  Abstract In this paper, we study model transitions for the Langlands quotient of GL 4 ⁢ n ⁢ ( F ) {\mathrm{GL}_{4n}(F)} corresponding to σ | ⋅ | 1 2 × σ ∨ | ⋅ | - 1 2 {\sigma|\cdot|^{\frac{1},{2 } }\times\sigma^{\vee}|\cdot|^{-\frac{1},{2 } } } with an irreducible tempered representation σ of GL 2 ⁢ n ⁢ ( F ) {\mathrm{GL}_{2n}(F)} when F is p -adic field.In particular, we explicitly construct an isomorphism between Sp 4 ⁢ n ⁢ ( F ) {\mathrm{Sp}_{4n}(F)} -distinguished models andcertain degenerate Whittaker models for the above Langlands quotient.

  Walter de Gruyter GmbH, Jul. 2026, Forum Mathematicum, 38(4) (4), 977 - 1008, English

  [Refereed]

  Scientific journal


• On gamma factors of Rankin–Selberg integrals for U_{2\ell} × Res_{E \slash F}GL_n

  Kazuki Morimoto

  Elsevier BV, Apr. 2025, Journal of Number Theory, 269, 203 - 246

  Scientific journal

  Link to Kobe Univ. Repository (Kernel)


• On the Gan–Gross–Prasad conjecture and its refinement for (U(2n), U(1))

  Masaaki Furusawa, Kazuki Morimoto

  Springer Science and Business Media LLC, Mar. 2025, Mathematische Annalen, 391(3) (3), 3799 - 3862, English

  [Refereed]

  Scientific journal


• On the Gross–Prasad conjecture with its refinement for (SO(5), SO(2)) and the generalized Böcherer conjecture

  Masaaki Furusawa, Kazuki Morimoto

  We investigate the Gross–Prasad conjecture and its refinement for the Bessel periods in the case of $(\mathrm {SO}(5), \mathrm {SO}(2))$ . In particular, by combining several theta correspondences, we prove the Ichino–Ikeda-type formula for any tempered irreducible cuspidal automorphic representation. As a corollary of our formula, we prove an explicit formula relating certain weighted averages of Fourier coefficients of holomorphic Siegel cusp forms of degree two, which are Hecke eigenforms, to central special values of $L$ -functions. The formula is regarded as a natural generalization of the Böcherer conjecture to the non-trivial toroidal character case.

  Wiley, Sep. 2024, Compositio Mathematica, 160(9) (9), 2115 - 2202

  Scientific journal

  Link to Kobe Univ. Repository (Kernel)


• On a certain local identity for Lapid–Mao’s conjecture and formal degree conjecture : even unitary groups case

  Kazuki Morimoto

  Abstract Lapid and Mao formulated a conjecture on an explicit formula of Whittaker–Fourier coefficients of automorphic forms on quasi-split reductive groups and metaplectic groups as an analogue of the Ichino–Ikeda conjecture. They also showed that this conjecture is reduced to a certain local identity in the case of unitary groups. In this article, we study the even unitary-group case. Indeed, we prove this local identity over p-adic fields. Further, we prove an equivalence between this local identity and a refined formal degree conjecture over any local field of characteristic zero. As a consequence, we prove a refined formal degree conjecture over p-adic fields and get an explicit formula of Whittaker–Fourier coefficients under certain assumptions.

  Cambridge University Press (CUP), Jul. 2022, Journal of the Institute of Mathematics of Jussieu, 21(4) (4), 1107 - 1161

  Scientific journal


• On algebraicity of special values of symmetric 4-th and 6-th power L-functions for $$\mathrm {GL}(2)$$

  Kazuki Morimoto

  Springer Science and Business Media LLC, Dec. 2021, Mathematische Zeitschrift, 299(3-4) (3-4), 1331 - 1350, English

  [Refereed]

  Scientific journal

  Link to Kobe Univ. Repository (Kernel)


• Refined global Gross–Prasad conjecture on special Bessel periods and Böcherer’s conjecture

  Masaaki Furusawa, Kazuki Morimoto

  European Mathematical Society - EMS - Publishing House GmbH, 2021, J. Eur. Math. Soc., 23(4) (4), 1295 - 1331

  [Refereed]

  Scientific journal


• On L-functions for U_{2n+1} × Res_{E/F} GL_m (m > n)

  Kazuki Morimoto, David Soudry

  Nov. 2020, J. Number Theory, 216(2020) (2020), 83 - 141, English

  [Refereed]


• Model Transition for Representations of Unitary Type

  森本和輝

  Feb. 2020, International Mathematics Research Notices, vol.2020(No.4) (No.4), 1112 - 1203

  [Refereed]


• On the irreducibility of global descents for even unitary groups and its applications

  Kazuki Morimoto

  American Mathematical Society, 2018, Transactions of the American Mathematical Society, 370(9) (9), 6245 - 6295, English

  [Refereed]

  Scientific journal


• On tensor product L-functions for quaternion unitary groups and GL(2) over totally real number fields: mixed weight cases

  Kazuki MORIMOTO

  2018, Adv. Math, 337, 317 - 362, English

  [Refereed]

  Scientific journal


• On special Bessel periods and the Gross-Prasad conjecture for SO(2n+1) x SO(2)

  Masaaki Furusawa, Kazuki Morimoto

  Jun. 2017, MATHEMATISCHE ANNALEN, 368(1-2) (1-2), 561 - 586, English

  [Refereed]

  Scientific journal


• On special values of certain L-functions II

  Masaaki Furusawa, Kazuki Morimoto

  Aug. 2016, AMERICAN JOURNAL OF MATHEMATICS, 138(4) (4), 1117 - 1166, English

  [Refereed]

  Scientific journal


• On L-functions for quaternion unitary groups of degree 2 and GL(2) (with an Appendix by M. Furusawa and A. Ichino)

  Kazuki Morimoto

  Oxford University Press, 2014, International Mathematics Research Notices, 2014(7) (7), 1729 - 1832, English

  [Refereed]

  Scientific journal


• On the theta correspondence for (GSp(4),GSO(4,2)) and Shalika periods.

  森本和輝

  2014, Represent. Theory, 18(2014) (2014), 28 - 87

  [Refereed]


• On special values of certain L-functions.

  森本和輝, Masaaki Furusawa

  2014, Amer. J. Math., 136(2014) (2014), 1385 - 1407

  [Refereed]


• Shalika periods on GU(2,2)

  Masaaki Furusawa, Kazuki Morimoto

  Dec. 2013, PROCEEDINGS OF THE AMERICAN MATHEMATICAL SOCIETY, 141(12) (12), 4125 - 4137, English

  [Refereed]

  Scientific journal

• ON THETA CORRESPONDENCES FOR (GSp$_4$, GSO$_{4,2}$) (Automorphic Representations and Related Topics)

  MORIMOTO KAZUKI

  Kyoto University, Dec. 2013, RIMS Kokyuroku, 1871, 203 - 206, English


• ON SPECIAL VALUES OF TENSOR PRODUCT L-FUNCTIONS OF AN INNER FORM OF GSP(4) AND GL(2) (Automorphic forms and automorphic L-functions)

  MORIMOTO KAZUKI

  Kyoto University, Mar. 2013, RIMS Kokyuroku, 1826, 1 - 6, English

• On an Ichino-Ikeda type formula for Whittaker periods and theta lifts

  Kazuki Morimoto

  Postech-PMI Number Theory Seminar, Mar. 2026, English

  [Invited]


• On Whittaker periods for orthogonal groups and symplectic groups

  Kazuki Morimoto

  Japan-Taiwan Number Theory Conference, Sep. 2025, English

  [Invited]

  Invited oral presentation


• ユニタリ群上の Whittaker 周期の市野-池田型公式について

  森本 和輝

  代数学シンポジウム, Aug. 2025, Japanese

  [Invited]

  Invited oral presentation


• On Ichino-Ikeda Type Formula of Whittaker Periods for Unitary Groups

  Kazuki Morimoto

  Number Theory Seminar, National Center for Theoretical Sciences, Taiwan, Sep. 2024

  [Invited]


• On Ichino-Ikeda type formula of Whittaker periods for unitary groups

  Kazuki Morimoto

  Automorphic Forms and L-functions of higher rank, Queen Mary University of London, Sep. 2023

  [Invited]

  Invited oral presentation


• On Ichino-Ikeda type formula of Bessel periods for (U(2n), U(1)) and (GL(2n), GL(1))

  Kazuki Morimoto

  RIMS conference "Analytic and arithmetic aspects of automorphic representations", Jan. 2023

  [Invited]

  Oral presentation


• On Ichino-Ikeda type formula of Whittaker periods for even unitary groups

  森本 和輝

  第9回京都保型形式研究集会, Jun. 2022

  [Invited]


• On Ichino-Ikeda type formula of Whittaker periods for even unitary groups

  Kazuki Morimoto

  National University of Singapore, Representation Theory and Number Theory, Sep. 2021, English

  [Invited]


• (SO(5), SO(2))のBessel周期の市野-池田型の公式と一般化されたBoecherer予想

  森本 和輝

  早稲田大学整数論セミナー, Jun. 2021

  [Invited]


• On Ichino-Ikeda type formula of Bessel period for (SO(5),SO(2)).

  Kazuki Morimoto

  RIMS conference“Automorphic forms, Automorphic representations, Galois representations, and its related topics”, Jan. 2021

  Oral presentation


• On Gan-Gross-Prasad conjecture for (U(2n), U(1)) and (SO(5), SO(2))

  Kazuki Morimoto

  RIMS研究集会「保型形式と$L$関数の解析的, 幾何的, $p$進的研究」, Jan. 2020, English, 京都大学数理解析研究所

  [Invited]

  Oral presentation


• On Gan-Gross-Prasad conjecture for (U(2n), U(1)) and (SO(5),SO(2))

  Kazuki Morimoto

  南大阪保型表現セミナー, Nov. 2019, English, 大阪市立大学

  [Invited]

  Oral presentation


• On Gross-Prasad conjecture for (SO(2n+1), SO(2))

  森本和輝

  KIAS seminar, Sep. 2019, English, Korean Institute for Advanced Study

  [Invited]

  Oral presentation


• On Gan-Gross-Prasad conjecture for (U(2n), U(1))

  森本和輝

  Representation Theory Workshop 2019, Aug. 2019, English, National University of Singapore, International conference

  [Invited]

  Oral presentation


• 対称積L 関数の特殊値とRamakrishnan-Shahidi lift の周期関係式について

  Kazuki MORIMOTO

  談話会, Nov. 2018, Japanese, 京都大学, Domestic conference

  [Invited]

  Invited oral presentation


• U(2n) のWhittaker 周期の明示公式について

  Kazuki MORIMOTO

  九州代数的整数論2018, Mar. 2018, Japanese, 九州大学, Domestic conference

  [Invited]

  Invited oral presentation


• On a certain local identity for an explicit formula of Whittaker periods on the even unitary group

  Kazuki MORIMOTO

  Special values of automorphic L-functions, periods of automorphic forms and related topics, Sep. 2017, English, 大阪市立大学, International conference

  Oral presentation


• 次数2 のSiegel モジュラー形式のL 函数の中心値の明示公式について

  Kazuki MORIMOTO

  東京電機大学数学講演会, Jun. 2017, Japanese, 東京電機大学, Domestic conference

  [Invited]

  Invited oral presentation


• On a certain local identity for Lapid-Mao's conjecture in the even unitary group case

  Kazuki MORIMOTO

  神戸整数論集会2017, Jun. 2017, English, 神戸大学, International conference

  [Invited]

  Invited oral presentation


• Refined Gross-Prasad conjecture on special Bessel periodsfor $\mathrm{SO}(2n+1) \times \mathrm{SO}(2)$

  MORIMOTO Kazuki

  Workshop on Shimura varieties, representation theory and related topics, Nov. 2016, English, Kyoto University, Kyoto University, Domestic conference

  [Invited]

  Invited oral presentation


• ($\mathrm{SO}(2n+1), \mathrm{SO}(2))$ の場合のGross-Prasad予想とSpecial Bessel 周期について

  MORIMOTO Kazuki

  代数セミナー, May 2016, Japanese, Touhoku University, Touhoku University, Domestic conference

  [Invited]

  Invited oral presentation


• 次数2 のSiegel モジュラー形式のSpecial Bessel 周期とL 函数の中心値について

  MORIMOTO Kazuki

  早稲田大学整数論セミナー, Apr. 2016, Japanese, Weseda University, Weseda University, Domestic conference

  [Invited]

  Invited oral presentation

• 日本数学会

  2013

• L函数の特殊値の明示公式

  森本 和輝

  Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C), Grant-in-Aid for Scientific Research (C), Kobe University, Apr. 2021 - Mar. 2026

  LapidとMaoにより予想されたU(2n)のWhittaker周期の明示公式は、ある局所等式の証明へと還元されていた。これまでの研究で非分裂非アルキメデス素点ではその局所等式は証明できていた。今年度の成果として、分裂非アルキメデス素点において、非分裂の場合と同様に適当なモデルの変換公式を証明することで、この局所等式を証明した。さらに、分裂アルキメデス素点で、Beuzart-PlessisによるGL(n)のtempered表現の大域化についての結果を用いることで、局所等式をGL(2n)の場合のWhittaker周期の明示公式へと帰着できることがわかった。この場合の明示公式はLapidとMaoにより証明されており、結果として分裂アルキメデス素点において局所等式を証明することができた。これらの結果から、非分裂実素点においてdiscrete seriesという仮定の下で、Whittaker周期の明示公式を証明することができた。特に、基礎体がtotally imginaryの場合には、任意のカスピダル保型表現について明示公式が証明できたことになる。さらに、この結果と古澤昌秋(大阪公立大)との共同研究で得た結果を組み合わせることにより、同様の仮定の下でtemperedなカスピダル保型表現に関して、(U(2n), U(1))の場合の精密化Gan-Gross-Prasad予想を証明することができた。また、U(2n+1)の場合のWhittaker周期の明示公式を証明するために、U(2n)との間のテータ対応を考察し、U(2n)のWhittaker周期がU(2n+1)のWhittaker周期へと移ることがわかった。


• 保型L函数の特殊値の明示式とその応用

  森本 和輝

  学術研究助成基金助成金／若手研究(B), Apr. 2017 - Mar. 2021, Principal investigator

  Competitive research funding


• 保型表現とL函数の特殊値

  森本 和輝

  学術研究助成基金助成金／若手研究(B), Apr. 2014 - Mar. 2018, Principal investigator

  Competitive research funding