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Ashay A. Burungale

Publications and source records attributed to Ashay A. Burungale.

9 recordsLinked to original sources
arXiv2025

Hecke $L$-values, definite Shimura sets and Mod $\ell$ non-vanishing

Let $λ$ be a self-dual Hecke character over an imaginary quadratic field $K$ of infinity type $(1,0)$. Let $\ell$ and $p$ be primes which are coprime to $6N_{K/\mathbb{Q}}({\mathrm cond}(λ))$. We determine the $\ell$-adic valuation of Hecke $L$-values $L(1,λχ)/Ω_K$ as $χ$ varies over $p$-power order anticyclotomic characters over $K$. As an application, for $p$ inert in $K$, we prove the vanishing of the $μ$-invariant of Rubin's $p$-adic $L$-function, leading to the first results on the $μ$-invariant of imaginary quadratic fields at non-split primes. Our approach and results complement the work of Hida and Finis. The approach is rooted in the arithmetic of a CM form on a definite Shimura set.The application to Rubin's $p$-adic $L$-function also relies on the proof of his conjecture. Along the way, we present an automorphic view on Rubin's theory.

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arXiv2025

A rank zero $p$-converse to a theorem of Gross--Zagier, Kolyvagin and Rubin

Let $E$ be a CM elliptic curve defined over $\mathbb{Q}$ and $p$ a prime. We show that $${\mathrm corank}_{\mathbb{Z}_{p}} {\mathrm Sel}_{p^{\infty}}(E_{/\mathbb{Q}})=0 \implies {\mathrm ord}_{s=1}L(s,E_{/\mathbb{Q}})=0 $$ for the $p^{\infty}$-Selmer group ${\mathrm Sel}_{p^{\infty}}(E_{/\mathbb{Q}})$ and the complex $L$-function $L(s,E_{/\mathbb{Q}})$. Along with Smith's work on the distribution of $2^\infty$-Selmer groups, this leads to the first instance of the even parity Goldfeld conjecture: For $50\%$ of the positive square-free integers $n$, we have $ {\mathrm ord}_{s=1}L(s,E^{(n)}_{/\mathbb{Q}})=0, $ where $E^{(n)}: ny^{2}=x^{3}-x $ is a quadratic twist of the congruent number elliptic curve $E: y^{2}=x^{3}-x$.

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arXiv2025

On the Frobenius fields of abelian varieties over number fields

Let $A$ be a non-CM simple abelian variety over a number field $K$. For a place $v$ of $K$ such that $A$ has good reduction at $v$, let $F(A,v)$ denote the Frobenius field generated by the corresponding Frobenius eigenvalues. Assuming $A$ has connected monodromy groups, we show that the set of places $v$ such that $F(A,v)$ is isomorphic to a fixed number field has upper Dirichlet density zero. Assuming the GRH, we give a power saving upper bound for the number of such places.

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arXiv2019

On the non-triviality of the $p$-adic Abel-Jacobi image of generalised Heegner cycles modulo $p$, I: modular curves

Generalised Heegner cycles are associated to a pair of an elliptic Hecke eigenform and a Hecke character over an imaginary quadratic extension $K/\Q$. Let $p$ be an odd prime split in $K/\Q$ and $l\neq p$ an odd unramified prime. We prove the non-triviality of the $p$-adic Abel-Jacobi image of generalised Heegner cycles modulo $p$ over the $\Z_l$-anticylotomic extension of $K$. The result is an evidence for the refined Bloch-Beilinson and the Bloch-Kato conjecture. In the case of two, it provides a refinement of the results of Cornut and Vatsal on the non-triviality of Heegner points over the $\Z_l$-anticylotomic extension of $K$.

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arXiv2019

Horizontal non-vanishing of Heegner points and toric periods

Let $F/\mathbb{Q}$ be a totally real field and $A$ a modular $\GL_2$-type abelian variety over $F$. Let $K/F$ be a CM quadratic extension. Let $χ$ be a class group character over $K$ such that the Rankin-Selberg convolution $L(s,A,χ)$ is self-dual with root number $-1$. We show that the number of class group characters $χ$ with bounded ramification such that $L'(1, A, χ) \neq 0$ increases with the absolute value of the discriminant of $K$. We also consider a rather general rank zero situation. Let $π$ be a cuspidal cohomological automorphic representation over $\GL_{2}(\BA_{F})$. Let $χ$ be a Hecke character over $K$ such that the Rankin-Selberg convolution $L(s,π,χ)$ is self-dual with root number $1$. We show that the number of Hecke characters $χ$ with fixed $\infty$-type and bounded ramification such that $L(1/2, π, χ) \neq 0$ increases with the absolute value of the discriminant of $K$. The Gross-Zagier formula and the Waldspurger formula relate the question to horizontal non-vanishing of Heegner points and toric periods, respectively. For both situations, the strategy is geometric relying on the Zariski density of CM points on self-products of a quaternionic Shimura variety. The recent result \cite{Ts, YZ, AGHP} on the André-Oort conjecture is accordingly fundamental to the approach.

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arXiv2017

Horizontal variation of Tate--Shafarevich groups

Let $E$ be an elliptic curve over $\mathbb{Q}$. Let $p$ be an odd prime and $ι: \overline{\mathbb{Q}}\hookrightarrow \mathbb{C}_p$ an embedding. Let $K$ be an imaginary quadratic field and $H_{K}$ the corresponding Hilbert class field. For a class group character $χ$ over $K$, let $\mathbb{Q}(χ)$ be the field generated by the image of $χ$ and $\mathfrak{p}_χ$ the prime of $\mathbb{Q}(χ)$ above $p$ determined via $ι_p$. Under mild hypotheses, we show that the number of class group characters $χ$ such that the $χ$-isotypic Tate--Shafarevich group of $E$ over $H_{K}$ is finite with trivial $\mathfrak{p}_χ$-part increases with the absolute value of the discriminant of $K$.

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arXiv2015

On the non-triviality of the $p$-adic Abel-Jacobi image of generalised Heegner cycles modulo $p$, II: Shimura curves

Generalised Heegner cycles are associated to a pair of an elliptic newform and a Hecke character over an imaginary quadratic extension $K/\Q$. The cycles live in a middle dimensional Chow group of a Kuga-Sato variety arising from an indefinite Shimura curve over the rationals and a self product of a CM abelian surface. Let $p$ be an odd prime split in $K/\Q$. We prove the non-triviality of the $p$-adic Abel-Jacobi image of generalised Heegner cycles modulo $p$ over the $\Z_p$-anticylotomic extension of $K$. The result implies the non-triviality of the generalised Heegner cycles in the top graded piece of the coniveau filtration on the Chow group and proves a higher weight analogue of Mazur's conjecture. In the case of two, the result provides a refinement of the results of Cornut-Vatsal and Aflalo-Nekovář on the non-triviality of Heegner points over the $\Z_p$-anticylotomic extension of $K$.

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arXiv2013

On the $μ$-invariant of the cyclotomic derivative of Katz p-adic L-function

When the branch character has root number -1, the corresponding anticyclotomic Katz p-adic L-function identically vanishes. In this case, we study the $μ$-invariant of the cyclotomic derivative of Katz p-adic L-function. As an application, this proves the non-vanishing of the anticyclotomic regulator of a self-dual CM modular form with the root number -1. The result also plays a crucial role in the recent work of Hsieh on the Eisenstein ideal approach to a one-sided divisibility of the CM main conjecture.

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