Elliptic curve rank growth in multi-quadratic extensions

Abstract

In this article we give an algorithm to produce infinitely many explicit quadratic twists of a given elliptic curve over $\mathbb{Q}$ with a rational point and fixed root number. Moreover, under the Parity Conjecture (or other technical hypotheses), for each $n\ge 1$, we produce explicit multi-quadratic extensions $L_n$ of $\mathbb{Q}$, of degree $2^n$, such that the growth in rank from $\mathbb{Q}$ to $L_n$ is at least $\max \{2n+2^{n-1}-1,2^n-1\}$ when the root number of $E$ is $-1$, and at least $\max \{2n,2^{n-1}+2n-2\}$ when it is $+1$. As a result, assuming Parity, we exhibit elliptic curves over $\mathbb{Q}$ and extensions of degree $2^n$ where the rank after base-extension is greater than or equal to $32+\max \{2n,2^{n-1}+2n-2\}$ or $30+\max \{2n+2^{n-1},2^n\}$.

arXiv commentIn this version we incorporate a suggestion by Andrej Dujella. Our thanks to him for his suggestions, which improves Theorem 1.2, part 4(c)