Berry–Keating conjecture
Develop a rigorous quantization of a classical chaotic Hamiltonian, notably H = 1/2(xp + px) (or H = xp), with appropriate boundary conditions, whose self-adjoint quantization has eigenvalues equal to the ordinates of the nontrivial zeros of the Riemann zeta function.
References
The Berry-Keating conjecture suggests connections to classical chaotic Hamiltonian systems whose quantization might yield the desired operator. Specific proposals include $H =\frac 12( xp+px)$ (where $x$ is position and $p$ is momentum) with appropriate boundary conditions, though rigorous constructions remain elusive.
— The Riemann Hypothesis: Past, Present and a Letter Through Time
(2602.04022 - Connes, 3 Feb 2026) in Subsubsection Scattering theory and spectral interpretation