Parigi leads work on multimode squeezed-light generation using optical frequency combs, engineering large-scale reconfigurable networks of entangled/squeezed light modes for continuous-variable quantum information and multiparameter quantum metrology, alongside Nicolas Treps.
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.
Eugene Polzik's QUANTOP centre uses hot and ultracold atomic spin ensembles and mechanical membranes to generate squeezed, entangled, and single-photon states for quantum sensing and communication. Key directions include: (1) atomic magnetometry and electromagnetic induction imaging for biomedical applications (MEG/MCG-quality sensors); (2) entanglement between a macroscopic mechanical oscillator and an atomic spin ensemble; (3) quantum memory for light; (4) back-action-evading measurement schemes beyond the SQL; and (5) optical preamplification for MRI. QUANTOP heads the Copenhagen Center for Biomedical Quantum Sensing (CBQS), targeting quantum-enhanced disease diagnostics.
John Rarity's group works on quantum-enhanced measurements and free-space quantum key distribution. Research: (1) quantum imaging with undetected photons — mid-infrared gas sensing (CO2, CH4) exploiting entangled photon pairs, with only near-IR photons detected (startup QLM); (2) sub-shot-noise imaging using quantum-identical photon beams; (3) spin-photon interfaces (1D cavity with near-unit scattering efficiency); (4) compact satellite QKD transmitters (EPSRC Quantum Comms Hub). Highly relevant to quantum-enhanced sensing.
Siddiqi's Quantum Nanoelectronics Laboratory develops superconducting quantum circuits and near-quantum-limited parametric amplifiers for qubit readout, quantum feedback, and quantum-enhanced sensing, and directs cross-campus quantum information efforts at Berkeley and LBNL.
Anders Sørensen's Theoretical Quantum Optics group develops theories for controlling individual quantum systems (atoms, photons, solid-state emitters) with focus on quantum information processing and communication. Research includes protocols for quantum repeaters, quantum networks, optomechanical systems, and transduction between microwave and optical frequencies. Strong collaboration with experimental groups at NBI and internationally; core member of the Hy-Q centre.
Treps leads the Multimode Quantum Optics group at LKB. Research directions: (1) Multimode quantum frequency combs — synchronously pumped OPO (SPOPO) generates entangled networks of squeezed modes with configurable graph structure; first demonstration of quantum frequency comb with multimode squeezing (PRL 2012); (2) Quantum-enhanced multiparameter estimation — quantum Fisher information and multimode squeezing for simultaneous beyond-shot-noise parameter estimation (e.g., frequency comb spectral centroid and energy, PRX 2020); (3) Non-Gaussian quantum states — heralded generation of non-Gaussian cluster states for CV quantum computing; (4) Quantum metrological inequalities — relating non-locality to parameter estimation. Spin-off: Cailabs (multimode fiber light-shaping for telecom and industrial lasers). Co-director of QICS. ERC-funded.
Nicolas Treps' multimode quantum optics group (with Valentina Parigi and Claude Fabre) generates and characterises highly multimode squeezed and entangled states of light. Research: (1) optical frequency combs as multimode squeezed state resources — quantum metrology and sensing with frequency combs; (2) reconfigurable multimode squeezed state networks for quantum computing and sensing; (3) spatiotemporal squeezing with optical parametric amplifiers. Key for quantum-enhanced sensing with light.
Walschaers provides theoretical support for LKB's multimode quantum-optics team, working on entanglement structure, non-Gaussian states, and metrological usefulness of large-scale squeezed-light networks generated via frequency combs.
Xu works on frequency-dependent squeezed-light injection for quantum-enhanced gravitational-wave detection at LIGO and on trapped-cavity atom interferometry for precision tests of fundamental physics, bridging quantum optics and atom-based inertial sensing.