Barker leads the UCL Optomechanics Group, focusing on levitated nano/micro-oscillators in vacuum. Research directions: (1) Six-degree-of-freedom cooling — demonstrated simultaneous cavity cooling of all 6 DOF of a levitated nanoparticle (Nature Physics 2023, with Monteiro); (2) Sympathetic cooling of two nanoparticles via Coulomb interaction, squeezing transfer (Phys. Rev. Research 2023); (3) Dark matter searches — levitated nanoparticles as directional dark matter sensors sensitive to nuclear recoil and momentum transfer; QTFP-funded project 'Development of Levitated Quantum Optomechanical Sensors for Dark Matter Detection'; (4) Controlling mode orientations for directional force sensing near the quantum limit; (5) Quantum macroscopic superposition tests. Closely collaborates with Monteiro (theory), Bose (quantum entanglement tests), and Ghag (dark matter).
The Geraci group employs high-Q resonant sensors for ultra-sensitive force and field detection in searches for new physics beyond the Standard Model. Key thrusts: (1) Optically-trapped levitated dielectric nanospheres and microspheres achieving zeptonewton (10⁻²¹ N) force sensitivity, applied to probing short-range deviations from Newtonian gravity at micrometer scales; (2) ARIADNE, an international NMR-based experiment using superfluid ³He to search for the QCD axion via axion-mediated spin-dependent forces between a rotating mass and polarized nuclei; (3) Collaboration on MAGIS-100, the 100 m-tall atom interferometer at Fermilab for gravitational wave detection in the mid-band (0.3–10 Hz) and ultralight dark matter searches; (4) Cryogenic optical cavity dark matter comparisons with Gabrielse and Kovachy groups. Member of CFP Northwestern and CIERA. APS Francis M. Pipkin Award 2023.
Hetet's group couples NV-center ensemble electron spins in electrically or optically levitated micro-diamonds to the mechanical (rotational and translational) degrees of freedom of the host particle, demonstrating spin-dependent torques strong enough to deflect a cantilever, spin-cooling of levitated motion, and NMR performed on a levitating microparticle. This complements the well-established line of NV-ensemble quantum sensing experiments (DEER, NMR, T1-relaxometry) that reach pT/sqrt(Hz)-class sensitivities, extending the toolbox toward mechanical and single-atom/single-spin readout.
The Hosseini Lab (Quantum Atom Optics) investigates light–atom interactions in rare-earth crystals, room-temperature gases, and nanophotonic structures. Directions: (1) Quantum optical memories in Tm³⁺:YAG and Er³⁺-doped solids using atomic frequency comb (AFC) and gradient echo memory (GEM) protocols for telecom-wavelength quantum networking; demonstrated efficient storage of multi-dimensional telecom photons (Optica Quantum 2025, Phys. Rev. Appl. 2025); (2) Cooperative/collective light–matter interactions in periodic rare-earth ion arrays in nano/micro-photonic structures (collaboration with Oak Ridge NL, Aydin group) for enhanced quantum memory coherence; (3) Quantum squeezed light — applied to enhanced thermoreflectance sensing of electronic hotspots (Appl. Phys. Lett. 2024); (4) Coherent levitation of macroscopic sensors (DARPA YFA 2024, $500k): magnetic and optical trapping of mm-scale objects as high-Q oscillators for magnetometry, vibrational sensing, accelerometry, inertial, and force sensing. Lab actively seeking postdocs in integrated photonics, quantum memory, and levitation sensing (2024–2025). ASEE Curtis W. McGraw Research Award 2026.
Monteiro works on the theory and control of levitated optomechanical systems, including a stable 3D velocity feedback cooling scheme for independently controlling all three translational modes of an optically levitated nanoparticle with minimal cross-talk. Levitated optomechanics of this kind is being developed both as a force/impulse sensor of exquisite sensitivity and, in collaboration with UCL colleagues including Peter Barker, as a testbed for macroscopic quantum states relevant to proposed gravity-entanglement experiments.
Novotny leads the Photonics Lab with a primary focus on levitodynamics. Research directions: (1) Ground-state cooling of levitated nanoparticles — demonstrated quantum control and motional ground state cooling of silica nanospheres in cryogenic free space (Nature 2021) and all 6 degrees of freedom simultaneously via coherent scattering (Nature Physics 2023); (2) Quantum delocalization and matter-wave interference of levitated nanoparticles (arXiv 2408.01264, 2024); (3) Cavity-mediated long-range interactions between multiple levitated nanoparticles, enabling collective quantum sensing arrays; (4) Optical cold damping, measurement-free coherent feedback (PRL 2025); (5) 2D optoelectronics — graphene/hBN/TMD-based laser detectors and modulators. Heavily cited levitodynamics review (Science 2021, joint with Quidant). Group feeds into applications in quantum-limited force sensing and macroscopic quantum tests.
Quidant leads the Nanophotonic Systems Laboratory, developing hybrid integrated levitation platforms combining optical and RF fields. Research directions: (1) Measurement-free coherent optical feedback cooling of levitated nanoparticles (PRL 2025, phonon occupations ~100s); (2) Quantum sensing applications — ultra-sensitive force/acceleration sensing, directional dark matter detection with levitated sensors; (3) Meta-atom levitation — Mie-resonance high-permittivity particles in optical traps for extreme light-matter interaction; (4) Optofluidics — structured light for photothermal fluid control; (5) Cancer phototherapy — photothermal nanoparticle applications. Pioneer in nanoplasmonic tweezers, thermoplasmonics, and on-chip biosensing. Key co-author of Science levitodynamics review (2021).
Massimiliano Rossi's lab focuses on levitated systems, optical tweezers, and quantum measurement. Research: (1) optically levitated nanoparticles for force sensing and zeptonewton-scale measurements; (2) quantum measurement and control of levitated systems approaching the quantum ground state; (3) back-action-evading measurement schemes for levitated oscillators; (4) exploring quantum-to-classical transitions. The lab is developing levitated systems as sensors for dark matter and gravitational waves.
Hendrik Ulbricht's group pioneers levitated optomechanics and macroscopic quantum systems. Research: (1) optical levitation of nanoparticles for zeptonewton force sensing and quantum-to-classical transition tests; (2) magnetic levitation of micromagnets (diamagnetically stabilised) as ultralight dark matter detectors and magnetometers (fT/√Hz sensitivity demonstrated with LeMaMa levitated ferromagnet); (3) spin entanglement witness for quantum gravity (BMV experiment — levitated diamond with NV centre); (4) tests of the Diósi-Penrose model of wavefunction collapse. Multiple Reviews of Modern Physics; active in macroscopic quantum physics community.
Verlot works on nano-optomechanics and quantum-limited displacement/force sensing with nanowire and levitated resonators, exploring ultrasensitive force detection and fundamental measurement limits. In the broader landscape of NV-centre ensemble quantum sensing (DEER, nano-NMR, T1 relaxometry) operating near pT/sqrt(Hz) sensitivity, this work is complemented by mechanical quantum sensors at the force-sensitivity frontier.