Berengut works on the atomic structure theory underpinning next-generation clocks: highly charged ions, whose optical transitions are both extremely narrow and exceptionally sensitive to variation of fundamental constants and to new physics, and the thorium-229 nuclear clock. He identifies which ionic species and transitions maximise sensitivity to the physics of interest while remaining experimentally accessible, and computes the many-body structure needed to interpret them — work that has directly guided the experimental HCI clock programmes at PTB, MPIK and NIST. Positioned against the established body of NV-ensemble quantum sensing work — DEER, nanoscale NMR and T1 relaxometry protocols operating at pT/sqrt(Hz) field sensitivity — clocks and magnetometers are the two great classes of quantum sensor; his work is on the frequency side of the same estimation problem that fixes pT/sqrt(Hz) performance on the magnetic side. Theory PI with close experimental collaborations.

Chantler's group is built around the idea that X-ray measurements can be made accurate, not just precise: the X-ray Extended Range Technique (XERT) delivers absolute absorption coefficients at the 0.02 per cent level, which in turn allows XAFS to be used for quantitative structure determination and allows high-accuracy tests of atomic theory. The second thread is precision X-ray spectroscopy of highly charged ions and exotic atoms as a test of bound-state QED, where discrepancies between theory and experiment remain unresolved. Positioned against the established body of NV-ensemble quantum sensing work — DEER, nanoscale NMR and T1 relaxometry protocols operating at pT/sqrt(Hz) field sensitivity — this is precision measurement at the other end of the electromagnetic spectrum: the methodological common ground with pT/sqrt(Hz) NV ensemble sensing is the obsessive treatment of systematics and absolute calibration that separates a sensitive measurement from an accurate one. Borderline inclusion, kept because the group's core competency is metrology rather than X-ray applications.

Flambaum is one of the most cited atomic theorists alive and the intellectual source of a large fraction of the modern precision-AMO new-physics programme. His group computes the atomic and molecular structure factors that convert an experimental frequency shift into a bound on new physics: enhancement factors for electron and nuclear EDMs, atomic parity violation, the sensitivity of clock transitions to variation of the fine-structure constant, and — most relevant to quantum sensing — the response of atomic clocks, magnetometers and comagnetometers to ultralight/axion-like dark matter fields. He proposed much of the theory behind using networks of quantum sensors as dark matter detectors. Positioned against the established body of NV-ensemble quantum sensing work — DEER, nanoscale NMR and T1 relaxometry protocols operating at pT/sqrt(Hz) field sensitivity — his theory is what tells an experimentalist what a pT/sqrt(Hz) magnetometer or a 10^-18 clock actually constrains: without it, a spin-precession measurement is just a number. Theory group; a sensing postdoc would collaborate rather than join.

Develops computational methods (DFT + many-body perturbation theory, quantum embedding) to predict properties of spin defects for quantum sensing and computing. Directions: (1) first-principles prediction of coherence properties, zero-phonon lines, and spin-photon coupling for NV, SiC divacancy, Er, and other color center platforms; (2) high-throughput screening of novel spin defect candidates in 2D materials and oxides; (3) quantum embedding methods for strongly correlated defects. Director MICCoM; NAS member; Argonne senior scientist.

Hollenberg is the intellectual centre of gravity for diamond quantum sensing in Australia: a theorist-turned-programme-leader whose group develops NV-based quantum probes for biological systems and quantum-computing architectures in silicon and diamond. Current directions include the quantum-probe hyperspectral microscope, in which NV ensembles in a bulk diamond substrate report magnetic and spin-noise contrast from cells cultured directly on the surface; nanodiamond quantum probes for intracellular relaxometry and free-radical detection; theory of decoherence-based sensing (T1 relaxometry as a chemical-specificity channel rather than a nuisance); and single-cell magnetic resonance. He co-leads the Melbourne node of the ARC Centre of Excellence in Quantum Biotechnology (QUBIC) with Simpson and Hinde, which is explicitly chartered to build quantum sensors for live biology, including portable brain imagers. Positioned against the established body of NV-ensemble quantum sensing work — DEER, nanoscale NMR and T1 relaxometry protocols operating at pT/sqrt(Hz) field sensitivity — his programme is one of the small number worldwide that has carried those ensemble protocols all the way into cell culture and tissue rather than stopping at proof-of-principle magnetometry. Preferred attribute present: the group's emphasis is on sensitivity and biological specificity rather than device fabrication, and QUBIC funding runs to 2030 with recurring postdoc recruitment.

Kassal is the leading Australian theorist of quantum effects in light harvesting. He established the distinction between coherent processes and coherent states in photosynthesis — showing that under incoherent sunlight at steady state, wavelike motion per se does not enhance efficiency, while environment-assisted transport and supertransfer genuinely can — and has since developed a classification of the mechanisms by which coherence (excitonic, vibrational, or of the light field itself) can improve energy transport. He also pioneered quantum-computer algorithms for chemistry. A distinct and directly relevant thread is the theory of spectroscopy with non-classical light: what entangled or squeezed photons can reveal about molecular coherence that classical light cannot. Positioned against the established body of NV-ensemble quantum sensing work — DEER, nanoscale NMR and T1 relaxometry protocols operating at pT/sqrt(Hz) field sensitivity — his work is the theoretical counterpart to the quantum-biology ambitions of the NV community: where NV ensembles at pT/sqrt(Hz) try to detect the magnetic signatures of biological spin chemistry, Kassal asks what quantum coherence is actually doing in those systems and whether quantum light can interrogate it.

Olaya-Castro leads theoretical research on quantum phenomena in biological systems. Research directions: (1) Quantum coherence in photosynthesis — open quantum systems theory for energy transfer in light-harvesting complexes, probing whether quantum coherence provides functional advantage; vibronic coupling models for chromophore-protein complexes; (2) Counting statistics and noise in exciton and charge transfer; (3) Quantum thermodynamics of biomolecular machines — efficiency limits and entropy production in molecular motors; (4) Non-classical features of electronic/vibrational dynamics in chromophores; (5) Connections between quantum information measures and biological function. Collaborates with Bain and Llorente-Garcia on joint experiment/theory biosensing projects. Theoretical work only — no experimental activity.

Quiney (currently Head of School) is a theorist of coherent imaging and relativistic atomic structure. His signature contribution is the theory of X-ray free-electron-laser imaging of single particles, including the modelling of radiation damage and ionisation dynamics during the pulse — the question of whether you can extract structure faster than you destroy it — plus phase-retrieval algorithms for coherent diffractive imaging and ptychography. He also works on relativistic quantum chemistry and atomic structure. Positioned against the established body of NV-ensemble quantum sensing work — DEER, nanoscale NMR and T1 relaxometry protocols operating at pT/sqrt(Hz) field sensitivity — the connection is methodological rather than physical: his group develops the inverse-problem and photon-budget theory that governs how much information can be pulled out of a shot-noise-limited measurement, which is the same limit that fixes pT/sqrt(Hz) performance in NV ensembles. Theory-first PI with strong coupling to experimental synchrotron/XFEL programmes.

Rahman does large-scale atomistic modelling of semiconductor quantum devices: tight-binding and DFT calculations of donor and quantum-dot wavefunctions, valley physics, spin-orbit coupling, hyperfine interactions and the response of all of these to strain and electric field, at system sizes large enough to represent a real device. The group works hand-in-glove with the Morello, Dzurak, Simmons and Rogge experiments, and increasingly uses machine learning to invert measurements into structural information. Positioned against the established body of NV-ensemble quantum sensing work — DEER, nanoscale NMR and T1 relaxometry protocols operating at pT/sqrt(Hz) field sensitivity — the same first-principles machinery is what predicts the hyperfine and spin-bath environment that determines T2 — and therefore the achievable pT/sqrt(Hz) sensitivity — of any solid-state spin sensor, including NV. Computational PI; would suit a candidate wanting a theory/experiment bridge role.

Rogge (formerly Delft) works on the spectroscopy of individual dopant atoms in silicon: using transport, STM and microwave spectroscopy to read out the orbital, valley and spin structure of single donors and acceptors, including their coupling to strain, electric fields and each other. The group has mapped the wavefunctions of individual dopants and used acceptor spin-orbit coupling for electric-field-driven spin control. This is single-quantum-object measurement rather than device engineering. Positioned against the established body of NV-ensemble quantum sensing work — DEER, nanoscale NMR and T1 relaxometry protocols operating at pT/sqrt(Hz) field sensitivity — single-donor spectroscopy is the silicon analogue of single-NV work: the same questions about coherence, bath engineering and readout fidelity that fix pT/sqrt(Hz) ensemble performance appear here in a platform where the sensor can be placed with atomic precision and interrogated electrically rather than optically.