Hyperfine-induced decoherence in triangular spin-cluster qubits

TL;DR

This paper studies how hyperfine interactions cause decoherence in triangular spin-cluster qubits, finding that certain chirality-based states are significantly more robust, with decoherence times approaching milliseconds.

Contribution

It demonstrates that electrically controllable chirality eigenstates exhibit much longer decoherence times due to their decoupling from nuclear spins, offering a promising qubit encoding.

Findings

Chirality eigenstates have decoherence times approaching milliseconds.

Chirality states are decoupled from nuclear spin bath, enhancing robustness.

Eigenstates of total spin projection have shorter decoherence times.

Abstract

We investigate hyperfine-induced decoherence in a triangular spin-cluster for different qubit encodings. Electrically controllable eigenstates of spin chirality (C_z) show decoherence times that approach milliseconds, two orders of magnitude longer than those estimated for the eigenstates of the total spin projection (S_z) and of the partial spin sum (S_{12}). The robustness of chirality is due to its decoupling from both the total- and individual-spin components in the cluster. This results in a suppression of the effective interaction between C_z and the nuclear spin bath.