A Scheduler for the Active Volume Architecture

TL;DR

This paper introduces a scheduling strategy for the Active Volume architecture that improves resource estimation accuracy and demonstrates significant runtime speedups for quantum simulations.

Contribution

It presents a greedy scheduling algorithm and a novel formula for overheads, enhancing runtime predictions and enabling more efficient quantum circuit execution.

Findings

Achieved a 1.76x runtime speedup on a 4x4 Fermi-Hubbard circuit.

Reduced bridge- and stale-state-qubit overheads by 1.44x.

Showed reaction times are negligible for systems with fewer than 600 logical qubits.

Abstract

We improve the accuracy of Active Volume resource estimates by explicitly scheduling when Active Volume blocks execute. We present software that uses a greedy strategy to assign each logical qubit a role in each logical cycle (e.g., workspace, stale state storage, and bridge qubits). We empirically derive a novel formula for bridge- and stale-state-qubit overheads and improve the accuracy of runtime estimates, revealing that larger circuits can run on a given computer than previously predicted by analytic models. For a $4\times4$ Fermi-Hubbard simulation test circuit, this yields a $1.76\times$ runtime speedup with a $1.44\times$ reduction in bridge- and stale-state-qubit overheads compared to the model used in arXiv:2501.06165. Moreover, we show that for this test circuit, reaction times are insignificant in runtime estimates for computers with fewer than 600 logical qubits and that the number of reaction layers per logical cycle remains 1 in this regime. Our results pave the way for a full compilation pipeline for the Active Volume architecture and improved analytic resource estimates.