On Edwards' Speculation and a New Variational Method for the Zeros of the $Z$-Function
Yochay Jerby
TL;DR
This work reframes Edwards' speculative link between zeros of the core $Z_0(t)=\cos(\theta(t))$ and zeros of the Hardy $Z$-function within a novel variational paradigm built on Spira's high-order sections. By introducing the $A$-parameter space $\mathcal{Z}_N$ and the associated zeros $t_n(r)$, the authors prove that the Riemann Hypothesis is equivalent to the existence of non-colliding, real-zero trajectories along which $t_n(r)$ never meets $t_{n\pm1}(r)$ for all zeros $t_n$. They demonstrate shortcomings of the classical Newton method and the RS formula for this purpose, while showing that a carefully designed non-colliding path in $\mathcal{Z}_{[t_n/2]}$ provides a robust variational route to RH, validated through a detailed $730{,}120$-th zero example. The paper thus recasts RH as a nonlinear optimization problem in a high-dimensional parameter space, with potential discriminant-geometric and machine-learning–driven extensions that could illuminate the zero dynamics of $Z(t)$ beyond traditional analytic techniques.
Abstract
In his foundational book, Edwards introduced a unique "speculation" regarding the possible theoretical origins of the Riemann Hypothesis, based on the properties of the Riemann-Siegel formula. Essentially Edwards asks whether one can find a method to transition from zeros of $Z_0(t)=cos(θ(t))$, where $θ(t)$ is Riemann-Siegel theta function, to zeros of $Z(t)$, the Hardy $Z$-function. However, when applied directly to the classical Riemann-Siegel formula, it faces significant obstacles in forming a robust plausibility argument for the Riemann Hypothesis. In a recent work, we introduced an alternative to the Riemann-Siegel formula that utilizes series acceleration techniques. In this paper, we explore Edwards' speculation through the lens of our accelerated approach, which avoids many of the challenges encountered in the classical case. Our approach leads to the description of a novel variational framework for relating zeros of $Z_0(t)$ to zeros of $Z(t)$ through paths in a high-dimensional parameter space $\mathcal{Z}_N$, recasting the RH as a modern non-linear optimization problem.
