Beecroft Building, Department of Physics, University of Oxford, Parks Road, Oxford, OX1 3PU
Professor Arzhang Ardavan, University of Oxford
Abstract
The realization of effective quantum error correction protocols remains a central challenge in the development of scalable quantum computers. Employing high-dimensional quantum systems (qudits) can offer more hardware-efficient protocols than qubit-based approaches. Using electron-nuclear double resonance, we have explored the implementation of a logical qubit encoded on the four states of a I = 3/2 nuclear spin hyperfine-coupled to a S = 1/2 electron spin qubit; the encoding protects against the dominant decoherence mechanism in such systems, fluctuations of the quantizing magnetic field. We explore the dynamics of the encoded state both under a controlled application of the fluctuation and under natural decoherence processes [1]. Our results confirm the potential of these proposals for practical fault tolerant quantum memories.
However, a full implementation of this and related schemes requires projective measurement of the spin qubit, which, generally, remains challenging for molecular candidate systems. Addressing this, we have investigated the potential offered by DNA as an assembly technology for integrating molecular quantum components into electrical devices with high yield and high reproducibility [2].
[1] Demonstrating experimentally the encoding and dynamics of an error-correctable logical qubit on a hyperfine-coupled nuclear spin qudit, S Lim, MV Vaganov, J Liu, A Ardavan, Phys. Rev. Lett. 134, 070603 (2025)
[2] A scalable, reproducible platform for molecular electronic technologies, S Helmi, J Liu, K Andrews, R Schreiber, J Bath, HL Anderson, AJ Turberfield, A Ardavan, arXiv:2503.13642