The Use of Exchange Coupled Atom Qubits as Atomic‐Scale Magnetic Field Sensors
Abstract
Phosphorus atoms in silicon offer a rich quantum computing platform where both nuclear and electron spins can be used to store and process quantum information. While individual control of electron and nuclear spins has been demonstrated, the interplay between them during qubit operations has been largely unexplored. This study investigates the use of exchange‐based operation between donor bound electron spins to probe the local magnetic fields experienced by the qubits with exquisite precision at the atomic scale. To achieve this, coherent exchange oscillations are performed between two electron spin qubits, where the left and right qubits are hosted by three and two phosphorus donors, respectively. The frequency spectrum of exchange oscillations shows quantized changes in the local magnetic fields at the qubit sites, corresponding to the different hyperfine coupling between the electron and each of the qubit‐hosting nuclear spins. This ability to sense the hyperfine fields of individual nuclear spins using the exchange interaction constitutes a unique metrology technique, which reveals the exact crystallographic arrangements of the phosphorus atoms in the silicon crystal for each qubit. The detailed knowledge obtained of the local magnetic environment can then be used to engineer hyperfine fields in multi‐donor qubits for high‐fidelity two‐qubit gates.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Nov 29, 2022
- Source ID
- 10.1002/adma.202201625
Entities
People
- Brandur Thorgrimsson
- Daniel Keith
- Joris G Keizer
- Keshavi Charde
- Ludwik Kranz
- Michelle Simmons
- Rajib Rahman
- Samuel K Gorman
- Serajum Monir
- Yu He
Organizations
- Army Research Office
- Australian Research Council
- University of New South Wales