Noise-induced collective quantum state preservation in spin qubit arrays

TL;DR

This paper demonstrates that nuclear spin noise, traditionally seen as a decoherence source, can actually preserve the collective quantum state in multi-qubit spin arrays, using current technology without controlling nuclear fields.

Contribution

It reveals that nuclear spin interactions can induce state preservation in multi-qubit systems, a counterintuitive role reversal of environmental noise.

Findings

Nuclear noise can preserve quantum states in multi-qubit arrays.

State preservation achieved without controlling nuclear fields.

Implementation feasible with current gate-tuning techniques.

Abstract

The hyperfine interaction with nuclear spins (or, Overhauser noise) has long been viewed as a leading source of decoherence in individual quantum dot spin qubits. Here we show that in a coupled multi-qubit system consisting of as few as four spins, interactions with nuclear spins can have the opposite effect where they instead preserve the collective quantum state of the system. This noise-induced state preservation can be realized in a linear spin qubit array using current technological capabilities. Our proposal requires no control over the Overhauser fields in the array; only experimental control over the average interqubit coupling between nearest neighbors is needed, and this is readily achieved by tuning gate voltages. Our results illustrate how the role of the environment can transform from harmful to helpful in the progression from single-qubit to multi-qubit quantum systems.