Speaker
Description
High-dimensional nuclear spins are attractive candidates for use as ancillas in quantum computation, given their exceptionally long coherence times, and could also help scale down the size of quantum processors. Nuclear spin qubits and qudits have been studied extensively in donor-based silicon platforms, but Group IV atoms such as ⁷³Ge — which possesses a high-spin nucleus isoelectronic with Si — remain comparatively understudied. Combining isoelectronic nuclei with quantum dots enables better control of electron tunnelling rates and greater tunability of hyperfine coupling via exchange gates. The weaker hyperfine coupling in quantum dot architectures, relative to donors, lowers the energy cost of moving the electron spin away from the nuclear spin, thereby enabling shuttling while preserving nuclear spin coherence. Here, we detect the presence of a single ⁷³Ge spin coupled to a single electron-spin qubit in a 4-dot SiMOS array and initialise the ⁷³Ge spin in the 9/2 and −9/2 states. Using a novel frequency-tracking method built on an Adiabatic Electron Spin Resonance (ESR) experiment, we resolve 10 equally spaced resonance peaks (~80–90 kHz spacing) corresponding to the 10 levels of the ⁷³Ge Hilbert space. The adiabatic pulse, grounded in Quantum Adiabatic Theory, employs simultaneous amplitude and instantaneous frequency shaping to produce a near-binary response, enabling a fast single-shot protocol for frequency tracking. This method resolves the low hyperfine couplings between nuclear and electron spins and can initialise the nuclear spin into its highest or lowest level through repeated pulsing. These results advance and add robustness to quantum computation architectures based on high-spin nuclei coupled to SiMOS quantum dots.
| I am the presenting author | Yes |
|---|