Technique - (31) Coherent control of solid-state spins

Type: Experimental

Description: Optically or microwave-driven coherent manipulation of spin qubits in diamond, SiC, or Er-doped hosts.

Department(s)/lab(s): Physics / QET Labs | Oulton Group @ Bristol
Summary:

Ruth Oulton's group works on quantum photonics using solid-state single-photon emitters. Research: (1) semiconductor quantum dot single-photon sources — cavity-enhanced emission, photonic crystal integration; (2) hBN defect spin-photon interfaces; (3) integrated quantum photonics for sensing and quantum networks. The group focuses on device-quality semiconductor photonic systems for quantum information and sensing applications.

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 — the group's stated target is single-spin inductive detection — 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 — DEER, nanoscale NMR and T1 relaxometry protocols operating at pT/sqrt(Hz) field sensitivity — 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 | 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 — 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.

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).

Department(s)/lab(s): Physics / C2N (Centre de Nanosciences et Nanotechnologies) | Quantum Photonics Group (Senellart Lab, C2N) @ Paris-Saclay
Summary:

Pascale Senellart's group at C2N develops the world's most efficient and bright quantum dot single-photon sources. Research: (1) high-efficiency single-photon emitters based on semiconductor quantum dots in micropillar cavities — up to 99% efficiency, >98% photon purity; (2) entangled photon pair sources; (3) photonic integrated circuits for quantum information and sensing. Coordinator of Quantum-Saclay ecosystem; co-founder of Quandela (quantum photonics spinoff). Key for quantum sensing with non-classical light.

Department(s)/lab(s): School of Physics | Atomic Fabrication Facility (Simmons) @ UNSW
Summary:

Simmons pioneered atomic-precision fabrication in silicon: hydrogen-resist STM lithography, phosphine dosing and epitaxial silicon overgrowth to place individual dopant atoms with sub-nanometre accuracy, then measure them at millikelvin. The programme has produced single-atom transistors, precision dopant arrays used as analogue quantum simulators, and the largest atom-scale device platform in the world; she also founded Silicon Quantum Computing Pty Ltd. The sensing-relevant capability is the single-electron transistor as an exquisitely sensitive electrometer, capable of resolving individual charge transitions and mapping local electrostatic potential at the atomic scale. 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 — her SET electrometry is the charge-domain counterpart to magnetic NV sensing at pT/sqrt(Hz): both are single-quantum-object detectors whose performance is limited by back-action and by the noise of the readout chain. Very large group, strongly fabrication-oriented and commercially entangled, which cuts against the stated preference for sensitivity-limited rather than fabrication-limited work.

Department(s)/lab(s): Electrical Engineering & Computer Sciences and Physics | Sipahigil Berkeley Quantum Devices Group @ UCB
Summary:

Sipahigil leads the Berkeley Quantum Devices Group, which integrates diamond and silicon-carbide color-center spin qubits with nanophotonic cavities to build quantum networks and solid-state quantum sensors, spanning superconducting circuits to color-center-based quantum memories. The group is actively recruiting postdocs.

Department(s)/lab(s): Materials | Photonic Nanomaterials Group @ Oxford
Summary:

Smith leads the Photonic Nanomaterials Group, studying nanostructured materials (semiconductor nanocrystals, diamond colour centres) coupled to open-access tunable optical microcavities, with applications spanning efficient spin-photon interfaces for NV-diamond quantum networks and single-photon sources.

Department(s)/lab(s): School of Physics | Wood Diamond Magnetometry Group @ UMelb
Summary:

Wood works on NV centres in physically rotating diamond, a niche he essentially created: by spinning the crystal at tens of kHz he has demonstrated spin-rotation coupling, geometric phases and rotationally-induced pseudo-fields on NV ensembles, and used the rotating frame as a resource for noise-averaging and for gyroscopy. The group also works on conventional bulk NV magnetometry, dynamical decoupling sequence design and nuclear-spin bath 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 — his rotating-frame protocols are a direct attempt to extend the DEER/T1-relaxometry toolbox — normally applied to static ensembles at pT/sqrt(Hz) — into a regime where the sensor itself is in motion, with obvious relevance to inertial sensing and to averaging away static field gradients. Early-career PI, smaller group; a good option for a candidate wanting substantial independence.

Department(s)/lab(s): School of Electrical Engineering and Telecommunications | Yang Silicon Qubit Systems Group @ UNSW
Summary:

Yang works on the systems-level physics of silicon spin qubits: operating qubits at elevated temperatures (above one kelvin, where cryo-CMOS control electronics can be co-integrated), valley and spin-orbit engineering, and the electrical control of spin qubits without micromagnets. The 'hot qubit' programme in particular is an engineering argument about where the classical/quantum boundary should sit in a real machine. 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 — raising the operating temperature of a spin sensor while preserving coherence is the same trade a pT/sqrt(Hz) NV ensemble makes implicitly by working at room temperature; Yang's work is the silicon community's attempt to buy back some of that convenience. Borderline inclusion — this is quantum computing rather than sensing — retained under the inclusive rubric.