Quantum cellular automata for quantum error correction and density classification

TL;DR

This paper introduces quantum cellular automata with built-in quantum error correction, demonstrating their potential to maintain quantum information integrity through local, automated updates inspired by classical density classification rules.

Contribution

The paper proposes and analyzes quantum cellular automata capable of quantum error correction, bridging a gap in understanding their long-range order and error correction abilities.

Findings

Quantum cellular automata can perform quantum error correction.

Simulations show they can preserve quantum information over multiple steps.

Designs based on classical rules demonstrate practical error correction potential.

Abstract

Quantum cellular automata are alternative quantum-computing paradigms to quantum Turing machines and quantum circuits. Their working mechanisms are inherently automated, therefore measurement free, and they act in a translation invariant manner on all cells/qudits of a register, generating a global rule that updates cell states locally, i.e., based solely on the states of their neighbors. Although desirable features in many applications, it is generally not clear to which extent these fully automated discrete-time local updates can generate and sustain long-range order in the (noisy) systems they act upon. In special, whether and how quantum cellular automata can perform quantum error correction remain open questions. We close this conceptual gap by proposing quantum cellular automata with quantum-error-correction capabilities. We design and investigate two (quasi-)one dimensional quantum cellular automata based on known classical cellular-automata rules with density-classification capabilities, namely the local majority voting and the two-line voting. We investigate the performances of those quantum cellular automata as quantum-memory components by simulating the number of update steps required for the logical information they act upon to be afflicted by a logical bit flip. The proposed designs pave a way to further explore the potential of new types of quantum cellular automata with built-in quantum error correction capabilities.