Degen leads the Spin Physics and Imaging group, one of the world's leading NV-center magnetometry labs. Research directions (as of 2025): (1) Scanning NV magnetometry of quantum materials — NV-tipped cantilevers image current flow (≲50 nm resolution) in graphene heterostructures and resolve domain walls in antiferromagnets/ferroelectrics; cryogenic scanning down to 350 mK in dilution refrigerator (published Appl. Phys. Lett. 2022). (2) Single-molecule NMR — shallow NV centers detect nuclear spins from surface-adsorbed molecules with sub-nanometer 3D resolution; 2022 Nano Lett. on amine-functionalized diamond surfaces; exploring chirality-induced spin selectivity at few-molecule level. (3) NV magnetometry protocols — reconstruction-free waveform sensing (1.1 ns time resolution, Nature 2025), gradiometric detection, spectrum demodulation for rapid scanning, multi-NV addressing. (4) Diamond nanoengineering — multicone pillar waveguides, surface engineering, scanning probe fabrication. ERC Proof-of-Concept 2025 for photonic IC single-photon NV excitation/detection for commercial quantum sensing.
Jean-François Roch (Professor at ENS Paris-Saclay, LuMIn) is a world leader in NV-center diamond quantum sensors. Research: (1) NV center magnetometry — scalar and vector magnetic field sensing with ensembles and single NV spins; (2) NV centers in diamond anvil cells for high-pressure magnetometry (world record 240 GPa); (3) joint laboratory (JRL) with Thales R&T on industrial NV quantum sensors; (4) color centres in hBN. IUF Senior Member 2021; Jaffé Prize + Berthelot Medal 2024.
Xu leads the Experimental Quantum Engineering group with a joint ETH–PSI appointment. Research directions: (1) Superconducting circuit quantum sensing — using qubits-as-sensors for detecting weak microwave signals beyond standard quantum limits, quantum non-demolition readout of photon fields; (2) Quantum error correction enabled sensing — integrating bosonic codes (cat qubits, binomial codes) into sensing protocols; (3) Quantum acoustics — coupling superconducting qubits to surface acoustic wave (SAW) resonators for hybrid quantum sensing; (4) Novel quantum hardware at PSI — leveraging PSI's infrastructure for cryogenic device fabrication and testing. Connected to the ETH–PSI Quantum Computing Hub.