Tags - (26) spin qubits

Department(s)/lab(s): School of Physics | Electronic and Condensed Matter Physics Group (McCallum) @ UMelb
Summary:

McCallum works on the materials and detector physics of donor qubits in silicon and colour centres in diamond and silicon carbide: defect engineering by ion implantation and annealing, characterisation of the resulting spin coherence, and β€” most relevant to a sensing postdoc β€” the development of superconducting and semiconductor detectors capable of registering single implanted ions with near-unit efficiency, which is what turns implantation from a statistical process into a deterministic one. He also works on near-surface colour centres, where surface termination and Fermi-level control set the achievable coherence. 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€” his group supplies the near-surface, coherence-optimised spin ensembles that DEER, nanoscale NMR and T1-relaxometry protocols at pT/sqrt(Hz) sensitivity actually depend on.

Department(s)/lab(s): School of Physics | McCamey Spin Physics and ODMR Laboratory @ UNSW
Summary:

McCamey is, for a candidate coming from NV ensemble sensing, the single most methodologically adjacent PI at UNSW. His laboratory does optically and electrically detected magnetic resonance on spins that are not defects in diamond: photogenerated spin-correlated radical pairs, triplet excitons in organic semiconductors, singlet-fission intermediates, and molecular spin systems. The instrumentation is the same toolkit β€” pulsed EPR, ODMR, dynamical decoupling, relaxometry β€” applied to systems where the spin is created by light and reports on chemistry. He directs the UNSW node of ARC Exciton Science. 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€” his group runs precisely those pulse sequences (Hahn echo, DEER, relaxometry) on a different spin species, and radical-pair spin chemistry is one of the few plausible mechanisms by which biology could be genuinely quantum β€” which makes this a strong landing spot for someone wanting to keep the NV skill set but change the physical system. Preferred attributes present: sensitivity-limited spin measurement, quantum-biology relevance.

Department(s)/lab(s): School of Electrical Engineering and Telecommunications | Fundamental Quantum Technologies Laboratory (Morello) @ UNSW
Summary:

Morello heads the Fundamental Quantum Technologies Laboratory and is the person who first read out the spin of a single electron, and then a single nucleus, in silicon. Current directions: high-spin donors (antimony-123, with eight nuclear levels) used as qudits and as sensors of local strain and electric field; nuclear acoustic resonance, in which a strain wave rather than a magnetic field drives the nuclear spin; engineered decoherence experiments as tests of quantum foundations; and precision tomography of multi-qubit donor registers. The group's donors are among the longest-coherence solid-state spins known (seconds for nuclei). 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€” a single-donor nuclear spin in silicon is functionally an NV centre with better coherence and worse readout: the same DEER, dynamical-decoupling and nuclear-register protocols apply, and the group's high-spin qudit work is aimed at exactly the multi-level sensing enhancements that the NV community is now chasing. Preferred attribute present: sensitivity and coherence, not fabrication, are the limiting variables here.

Department(s)/lab(s): Physics and Astronomy | Odom Research Group @ Northwestern
Summary:

The Odom Group studies trapped molecular ions at millikelvin temperatures using radio-frequency ion traps. Key directions: (1) Controlled preparation and single-quantum-state readout of trapped molecular ions (e.g., AlH⁺, SiO⁺, N₂⁺) β€” combining laser cooling, blackbody-radiation-assisted state preparation, and fluorescence detection for single-molecule precision spectroscopy; (2) Search for time-variation of fundamental constants (electron-to-proton mass ratio, fine structure constant Ξ±) using molecular vibrational/rotational transitions as highly sensitive probes; (3) Quantum effects in sub-Kelvin chemistry β€” probing tunneling, orbiting resonances, and quantum state control of reactive collisions between cold molecules. Member of CFP Northwestern.

Department(s)/lab(s): School of Electrical Engineering and Telecommunications | Pla Quantum Spin Control and Sensing Laboratory @ UNSW
Summary:

Pla is the strongest single match in this cohort for a candidate whose background is sensitivity-limited spin detection. His laboratory does inductively-detected electron spin resonance at millikelvin using high-quality-factor superconducting microresonators, read out through Josephson and travelling-wave parametric amplifiers operating at the quantum limit of added noise. The result is ESR sensitivity improved by many orders of magnitude over commercial spectrometers β€” the group's stated target is single-spin inductive detection β€” and, in parallel, the development of near-ideal degenerate parametric amplifiers and squeezed microwave states as the readout resource that makes it possible. Applications explicitly include chemistry and biology, where the goal is to do EPR on samples far too small for a conventional spectrometer. 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€” this is the microwave-inductive route to the same destination: where an NV ensemble reaches pT/sqrt(Hz) by optical readout of many spins, Pla reaches comparable or better spin sensitivity by making the microwave detection chain quantum-limited, and the DEER and dynamical-decoupling sequences are shared verbatim. Preferred attribute present in the strongest form: cutting-edge sensitivity, not device fabrication, is the object.

Department(s)/lab(s): School of Physics | Rahman Atomistic Quantum Device Modelling Group @ UNSW
Summary:

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 β€” DEER, nanoscale NMR and T1 relaxometry protocols operating at pT/sqrt(Hz) field sensitivity β€” the same first-principles machinery is what predicts the hyperfine and spin-bath environment that determines T2 β€” and therefore the achievable pT/sqrt(Hz) sensitivity β€” of any solid-state spin sensor, including NV. Computational PI; would suit a candidate wanting a theory/experiment bridge role.

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

Reilly's Quantum Nanoscience Laboratory works on the interface between quantum devices and the classical control hardware needed to run them at scale β€” custom VLSI CMOS operating below 100 mK, high-bandwidth dispersive readout, and cryogenic microwave engineering β€” a programme built up during his long association with Microsoft's quantum effort. A distinct and directly relevant second thread is the manipulation of spin states in nanoparticles for new imaging modalities in medicine: hyperpolarisation and spin-state engineering of nanoparticle contrast agents, which is quantum control applied to MRI. 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€” the cryo-CMOS readout chain he builds is exactly the enabling technology that would let a pT/sqrt(Hz) spin-ensemble sensor be multiplexed into an array rather than run one channel at a time; and the nanoparticle-MRI thread is an independent route into biological spin sensing. Large group, strong engineering culture, significant industry entanglement.

Department(s)/lab(s): Department of Chemistry, Institute of Inorganic and Analytical Chemistry | AK Rentschler - Molecular Magnetism @ JGU
Summary:

Rentschler's group synthesizes and characterizes molecular magnetic materials: single-molecule magnets, spin-crossover complexes and polynuclear coordination clusters, with magnetic anisotropy engineered through ligand-field design and characterized by SQUID magnetometry, EPR and ab-initio calculations. The overlap with this search is the molecular-qubit angle -- these are the same chemical objects being pursued elsewhere as optically or electrically addressable spin qubits and as molecular quantum sensors. Relative to the established NV-ensemble quantum-sensing playbook (DEER, nanoscale NMR, T1 relaxometry at pT/sqrt(Hz) ensemble sensitivity), the value here is chemical: designed spin systems with tunable coherence and anisotropy, rather than defects in a host crystal. Borderline-strong inclusion; the group is chemistry-first, so a physicist postdoc would bring the spin-readout side.

Department(s)/lab(s): School of Physics | Rogge Single Dopant Spectroscopy Group @ UNSW
Summary:

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 β€” DEER, nanoscale NMR and T1 relaxometry protocols operating at pT/sqrt(Hz) field sensitivity β€” 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.

Department(s)/lab(s): Institute of Physics (QUANTUM) | Quantenbit (AG Schmidt-Kaler) @ JGU
Summary:

Quantenbit operates segmented micro-structured Paul traps for scalable trapped-ion quantum information and, increasingly, for quantum sensing. Directions: (i) trapped Rydberg ions -- combining the tight confinement of a Paul trap with the giant polarizability of Rydberg states, which is simultaneously a fast-gate resource and an extremely sensitive electric-field probe; (ii) motional-mode sensing of electric fields and surface noise; (iii) deterministic single-ion implantation, where a cold ion is extracted from the trap and implanted with nm-scale placement -- directly relevant to building NV/donor arrays with known ion counts, and to single-ion detection validation; (iv) TACTICa, applying ion-trapping and quantum-logic spectroscopy to 229Th toward a nuclear clock; (v) single-atom heat engines and quantum thermodynamics. Relative to the established NV-ensemble quantum-sensing playbook (DEER, nanoscale NMR, T1 relaxometry at pT/sqrt(Hz) ensemble sensitivity), the deterministic-implantation line is the natural upstream complement: it is the route to engineering NV ensembles/arrays with controlled density rather than relying on stochastic implantation. Strong local coupling to Budker (Th-229, exotic physics) and Wendt (laser ionization).