Technique - (22) Electron paramagnetic resonance (EPR)

Type: Experimental

Description: Spectroscopy of unpaired electron spins; used for structural biology, spin-label distance measurements, and quantum sensing.

Department(s)/lab(s): Chemistry | Anderson Lab @ UChicago
Summary:

Anderson's group designs molecular electron-spin qubit candidates -- including an air- and water-stable tetrathiafulvalene-bridged radical with spin centered on a nuclear-spin-free ligand -- that retain hundreds of nanoseconds of coherence in solution at room temperature, aiming toward solution-phase quantum sensing in biological environments. This complements solid-state NV-ensemble sensors, which use DEER, NMR, and T1-relaxometry protocols to reach pT/sqrt(Hz)-class magnetic sensitivity, by pursuing a chemically tunable molecular alternative that could operate directly in biological media.

Department(s)/lab(s): Physics (Condensed Matter Physics Sub-department) | Quantum Spin Dynamics Group @ Oxford
Summary:

Ardavan leads the Quantum Spin Dynamics group, studying quantum coherent phenomena in condensed matter. Central to the lab's quantum sensing relevance: (1) molecular spin qubits β€” using pulsed EPR/DEER to characterise and control multi-spin registers ({Cr7Ni} molecular rings, nitroxide radical chains) assembled into qubit networks, measuring coherence times, inter-qubit couplings, and demonstrating spin-electric coupling in molecular magnets; (2) DNA-assembled molecular quantum devices β€” using DNA nanostructures to precisely position molecular spin qubits for multi-qubit sensing and quantum information applications; (3) surface atom spin resonance β€” STM-based coherent spin control of individual atoms on surfaces at nanosecond timescales. Uses X-band through W-band pulsed EPR at Centre for Advanced Electron Spin Resonance (CAESR), Oxford.

Department(s)/lab(s): School of Physics | Quantum Integration Laboratory @ USyd
Summary:

Bartholomew trained with Sellars (ANU) and Faraon (Caltech) and runs the Quantum Integration Laboratory, which works on rare-earth ions (erbium, europium, ytterbium) in crystals and in nanophotonic devices. Rare-earth ions have the longest optical and spin coherence times of any solid-state emitter, which makes them simultaneously the best optical quantum memories and, less obviously, extremely good sensors: the group works on rare-earth-based microwave and RF quantum sensing, on-chip integration of ions with photonic and superconducting circuits, and telecom-band spin-photon interfaces. Positioned against the established body of NV-ensemble quantum sensing work β€” DEER, nanoscale NMR and T1 relaxometry protocols operating at pT/sqrt(Hz) field sensitivity β€” rare-earth ensembles are the closest solid-state analogue to NV ensembles, with narrower optical lines and longer coherence but cryogenic operation; protocols like DEER and dynamical-decoupling-enhanced sensing at pT/sqrt(Hz) map across directly. This is one of the best fits at Sydney for a solid-state spin-sensing candidate.

Department(s)/lab(s): School of Chemistry | Boskovic Molecular Magnetism Group @ UMelb
Summary:

Boskovic is a synthetic inorganic chemist working on lanthanoid and polyoxometalate molecular magnets, valence tautomeric and redox-switchable complexes, and the design of molecules whose spin states can be addressed and switched. The group's relevance to quantum sensing is that these are chemically tunable spin qubits: unlike solid-state defects, their coordination environment, nuclear-spin bath and anisotropy can be designed atom by atom, which is the argument for molecular qubits as sensors. Characterisation is by SQUID magnetometry, EPR and ab initio calculation. Positioned against the established body of NV-ensemble quantum sensing work β€” DEER, nanoscale NMR and T1 relaxometry protocols operating at pT/sqrt(Hz) field sensitivity β€” molecular spin qubits are the chemistry community's answer to the NV centre, and DEER/pulsed-EPR protocols developed for NV ensembles at pT/sqrt(Hz) transfer more or less directly to these systems. Borderline inclusion (synthesis-led rather than sensitivity-led), kept per the inclusive rubric.

Department(s)/lab(s): Chemistry – Photon Science Institute / National EPR Facility | Bowen Group (Molecular Spin Qubits and EPR) @ Manchester
Summary:

Bowen leads the CQSE 'Spins and Qubits' theme at Manchester, focusing on organometallic molecular spin qubits for quantum sensing and computing. Research directions: (1) Organometallic La(II) and other rare-earth molecular qudits β€” designing molecules with multiple accessible spin states (qudits) for encoding quantum information and sensing; (2) Pulsed EPR characterization β€” Hahn echo, ESEEM, ENDOR at X/W/Q-band to measure coherence times and hyperfine couplings; (3) Integration of molecular qubits into devices β€” surface deposition and nanoscale addressing; (4) Multi-spin sensing β€” using exchange-coupled spin pairs as differential sensors of magnetic field gradients. Closely collaborates with Tuna and Winpenny.

Department(s)/lab(s): Physics & Astronomy – Condensed Matter & Materials Physics | Breeze Lab (Solid-State Maser Quantum Sensing) @ UCL
Summary:

Breeze is a senior research fellow at UCL working on room-temperature solid-state masers. Research directions: (1) Pentacene maser β€” first demonstration of a room-temperature, continuous-wave solid-state maser (Science 2018) using photoexcited triplet-state pentacene in p-terphenyl crystal; achieving amplification with noise temperature near 1 K; (2) Diamond NV maser β€” developing NV-center-based maser for ultra-low-noise microwave amplification at room temperature, relevant to quantum sensing readout chains; (3) Maser applications β€” quantum-limited amplification for dark matter searches, MRI signal amplification, and quantum communication repeaters; (4) Spin dynamics β€” understanding triplet-state dynamics in organic crystals for spin polarization control. Strong relevance to quantum-limited microwave sensing.

Department(s)/lab(s): Physics – QOLS / Centre for Cold Matter | Centre for Cold Matter – Quantum Technology & Dark Matter (Devlin) @ Imperial
Summary:

Devlin is a Royal Society URF at the Centre for Cold Matter building a new experiment to detect axion and dark matter particles. His prior work at CERN's BASE collaboration (Penning trap antiproton experiment) used the ultra-sensitive superconducting detection circuit of a cryogenic Penning trap to set new constraints on axion-like particle couplings to photons (~2.79 neV/cΒ² range; PRL 2021). At Imperial he is developing a Penning trap single-photon counter concept using a single trapped electron to detect 30–60 GHz photons from axion-photon conversion in a strong magnetic field (arXiv 2601.05472, March 2026), targeting axion masses of 124–248 ΞΌeV. This approach could overcome the standard quantum noise limit that hampers conventional haloscope searches at high mass. Active PDRA posting open May 2025.

Department(s)/lab(s): Chemistry | Fataftah Lab @ UIUC
Summary:

Synthesizes and characterizes molecular magnets and metal-organic frameworks, using spectroscopy and electronic structure methods to design molecular spin qubits for quantum information science.

Department(s)/lab(s): Chemistry | Freedman Group @ MIT
Summary:

PREFERRED. Freedman uses synthetic inorganic chemistry to design molecular qubits from the electron spin of paramagnetic coordination complexes (e.g. chromium-centered complexes), giving Angstrom-scale, chemically tunable control over qubit placement and coherence for quantum sensing, communication, and metrology applications, including collaborations targeting dark-matter detection and biological/materials sensing; she directs the Institute-wide Quantum@MIT initiative.

Department(s)/lab(s): Department of Materials (D-MATL) | Magnetism and Interface Physics Group (Gambardella) @ ETH Zurich
Summary:

Gambardella leads the Magnetism and Interface Physics group at ETH D-MATL. Research directions: (1) Scanning probe magnetometry β€” using NV-center cantilevers (collaboration with Degen) and magneto-optical Kerr microscopy to image spin textures (skyrmions, domain walls) in thin-film heterostructures with sub-100 nm resolution; (2) Spin-orbit torques β€” current-induced magnetization switching via interfacial spin-orbit coupling; spin Hall and Rashba effects for spintronic devices; (3) Single-atom magnetism β€” STM and X-ray absorption for element-specific orbital and spin moments of individual atoms on surfaces; (4) XMCD at synchrotron β€” quantitative element-specific magnetic spectroscopy. Quantum sensing angle: spin-orbit driven phenomena, high-resolution magnetic imaging.