CQM: Cyclic Qubit Mappings

TL;DR

This paper introduces cyclic qubit mappings (CQM), a dynamic compilation technique that mitigates hardware heterogeneity in quantum error correction by maneuvering logical qubits, reducing error rates with minimal overhead.

Contribution

CQM is a novel dynamic remapping method during compilation that improves logical qubit error rates by adapting to hardware variability in surface code quantum computers.

Findings

CQM effectively reduces logical error rates in simulated quantum architectures.

CQM incurs minimal additional execution time compared to static mappings.

CQM enhances resource utilization in quantum error correction processes.

Abstract

Quantum computers show promise to solve select problems otherwise intractable on classical computers. However, noisy intermediate-scale quantum (NISQ) era devices are currently prone to various sources of error. Quantum error correction (QEC) shows promise as a path towards fault tolerant quantum computing. Surface codes, in particular, have become ubiquitous throughout literature for their efficacy as a quantum error correcting code, and can execute quantum circuits via lattice surgery operations. Lattice surgery also allows for logical qubits to maneuver around the architecture, if there is space for it. Hardware used for near-term demonstrations have both spatially and temporally varying error results in logical qubits. By maneuvering logical qubits around the topology, an average logical error rate (LER) can be enforced. We propose cyclic qubit mappings (CQM), a dynamic remapping technique implemented during compilation to mitigate hardware heterogeneity by expanding and contracting logical qubits. In addition to LER averaging, CQM shows initial promise given it's minimal execution time overhead and effective resource utilization.