Q-Pilot: Field Programmable Qubit Array Compilation with Flying Ancillas

TL;DR

Q-Pilot is a scalable compiler that leverages movable atoms called flying ancillas in neutral atom quantum arrays to optimize circuit compilation, significantly reducing circuit depth for various quantum applications.

Contribution

It introduces a novel compilation approach using flying ancillas for FPQA, inspired by FPGA strategies, to enhance parallelism and reduce circuit depth in quantum computing.

Findings

Achieves up to 27.7x reduction in circuit depth for quantum simulation.

Reduces circuit depth by 6.3x for QAOA circuits.

Demonstrates effectiveness on 100-qubit random circuits.

Abstract

Neutral atom arrays have become a promising platform for quantum computing, especially the field programmable qubit array (FPQA) endowed with the unique capability of atom movement. This feature allows dynamic alterations in qubit connectivity during runtime, which can reduce the cost of executing long-range gates and improve parallelism. However, this added flexibility introduces new challenges in circuit compilation. Inspired by the placement and routing strategies for FPGAs, we propose to map all data qubits to fixed atoms while utilizing movable atoms to route for 2-qubit gates between data qubits. Coined flying ancillas, these mobile atoms function as ancilla qubits, dynamically generated and recycled during execution. We present Q-Pilot, a scalable compiler for FPQA employing flying ancillas to maximize circuit parallelism. For two important quantum applications, quantum simulation and the Quantum Approximate Optimization Algorithm (QAOA), we devise domain-specific routing strategies. In comparison to alternative technologies such as superconducting devices or fixed atom arrays, Q-Pilot effectively harnesses the flexibility of FPQA, achieving reductions of 1.4x, 27.7x, and 6.3x in circuit depth for 100-qubit random, quantum simulation, and QAOA circuits, respectively.