Faster quantum chemistry simulations on a quantum computer with improved tensor factorization and active volume compilation

TL;DR

This paper introduces advanced tensor factorization and active volume compilation techniques to significantly accelerate quantum chemistry simulations on quantum computers, achieving two orders of magnitude speedup over previous methods.

Contribution

The authors develop a novel BLISS-THC framework and AV compilation method, enabling faster and more efficient electronic structure calculations on quantum hardware.

Findings

Achieved two-orders-of-magnitude runtime reduction for molecular simulations.

Developed the tightest Hamiltonian factorizations to date.

Provided detailed benchmarks for the P450 molecule.

Abstract

Electronic structure calculations of molecular systems are among the most promising applications for fault-tolerant quantum computing (FTQC) in quantum chemistry and drug design. However, while recent algorithmic advancements such as qubitization and Tensor Hypercontraction (THC) have significantly reduced the complexity of such calculations, they do not yet achieve computational runtimes short enough to be practical for industrially relevant use cases. In this work, we introduce several advances to electronic structure calculation for molecular systems, resulting in a two-orders-of-magnitude speedup of estimated runtimes over prior-art algorithms run on comparable quantum devices. One of these advances is a novel framework for block-invariant symmetry-shifted Tensor Hypercontraction (BLISS-THC), with which we achieve the tightest Hamiltonian factorizations reported to date. We compile our algorithm for an Active Volume (AV) architecture, a technical layout that has recently been proposed for fusion-based photonic quantum hardware. AV compilation contributes towards a lower runtime of our computation by eliminating overheads stemming from connectivity issues in the underlying surface code. We present a detailed benchmark of our approach, focusing primarily on the computationally challenging benchmark molecule P450. Leveraging a number of hardware tradeoffs in interleaving-based photonic FTQC, we estimate runtimes for the electronic structure calculation of P450 as a function of the device footprint.