Technique - (15) Cavity-QED single-atom trapping

Type: Experimental

Description: Trapping single neutral atoms in high-finesse optical or fibre-tip microcavities for deterministic single-photon generation and strong light-matter coupling.

Department(s)/lab(s): Physics / LKB | Cavity QED Group (Brune/Raimond) @ ENS Paris
Summary:

Michel Brune leads the Rydberg atoms / cavity QED group at LKB. Research: (1) circular Rydberg atoms trapped in high-finesse microwave cavities — quantum non-demolition measurement of photons, quantum state engineering; (2) fundamental quantum optics: decoherence, entanglement, quantum jumps, Schrödinger cat states; (3) quantum sensing of cavity fields with single atoms as probes. This group pioneered cavity QED experiments leading to the 2012 Nobel Prize (Haroche). Brune heads the laboratory.

Department(s)/lab(s): Physics – Laboratoire Kastler Brossel (ENS / Collège de France site) | Cavity QED / Circular Rydberg Atom Group (Brune/Raimond, LKB at Collège de France) @ Sorbonne
Summary:

Brune leads the Circular Rydberg Atom / Cavity QED group at LKB (Collège de France site), continuing the work of Serge Haroche (Nobel 2012). Note: Brune is employed by ENS, not Sorbonne Université; postdoc contracts are typically ENS/CNRS. Research directions: (1) Circular Rydberg atoms — atoms in extremely high principal quantum number states (n~50) with extremely long radiative lifetimes (~30 ms) and large dipole moments; (2) Cavity QED quantum sensing — single circular atoms probe the microwave field in a superconducting cavity photon-by-photon via quantum non-demolition measurement; (3) Quantum state engineering — generating Fock states, Schrödinger cat states, and entangled atom-field states in the cavity; (4) Tests of quantum complementarity — observing decoherence of mesoscopic superpositions in real time as a probe of quantum-to-classical transition. The 'quantum radio receiver' using single atoms to sense individual microwave photons is a landmark quantum sensing demonstration.

Department(s)/lab(s): Physics | LKB - Rydberg Atoms Team @ CNRS
Summary:

Gleyzes is a CNRS researcher in the Rydberg Atoms team at LKB (successor to Serge Haroche's cavity-QED group), where he achieved the first quantum non-demolition detection of a single microwave photon. The team now prepares non-classical states of circular Rydberg atoms as probes for electric- and magnetic-field sensing below the standard quantum limit, uses quantum optimal control to navigate large Rydberg Hilbert spaces, and has demonstrated millisecond-lived circular states at room temperature, a route toward practical Rydberg-atom quantum sensors and simulators.

Department(s)/lab(s): Physics – Laboratoire Kastler Brossel, Sorbonne Université | Quantum Fluids of Light Group (Glorieux Group / LKB) @ Sorbonne
Summary:

Glorieux leads the Quantum Fluids of Light and Nanophotonics group at LKB. Research directions: (1) Quantum fluids of light in atomic vapors — hot Rb/Cs vapor as paraxial photon fluids exhibiting superfluidity, soliton dynamics, and vortex formation; first analogue cosmological particle creation (Hawking effect) in a photon fluid (Nature Communications 2022); (2) Polariton superfluids — exciton-polariton microcavities for analogue gravity, Bogoliubov dispersion mapping, and first-order dissipative phase transitions; (3) Nanophotonics — coupling single quantum emitters (nanofiber-coupled atoms, perovskite nanocrystals) for quantum photonics and sensing; displacement sensor based on optical nanofiber; (4) Optical computing interfaces with quantum systems. Marie Curie IOF Fellow (2011), City of Paris Young Scientist Award (2015).

Department(s)/lab(s): Physics (Atomic and Laser Physics Sub-department) | Atom-Photon Connection Group @ Oxford
Summary:

Kuhn leads the Atom-Photon Connection group, working at the single-atom, single-photon level. Key research thrusts: (1) deterministic generation of indistinguishable single photons from single atoms in high-finesse cavities, with cluster-state production for one-way quantum computing; (2) development of integrated fibre-tip microcavities with small radius-of-curvature for >50% photon capture efficiency and direct fibre coupling; (3) single-photon quantum memories using cavity-coupled atom systems; and (4) optical trapping of single atoms in the Lamb-Dicke regime for quantum simulation and networking. The group uses reinforcement learning for optimal quantum control of atom-cavity systems.

Department(s)/lab(s): Physics – Laboratoire Kastler Brossel, Sorbonne Université | Quantum Networks Group (Laurat Group / LKB) @ Sorbonne
Summary:

Laurat leads the Quantum Networks team at LKB, developing quantum memories and atom-photon interfaces for quantum network applications. Research directions: (1) High-efficiency cold-atom quantum memories — DLCZ-protocol and AFC memories for telecom photons; demonstrating >90% efficiency and multimode operation; quantum cryptography integrating optical quantum memory (arXiv Mar 2025); (2) Waveguide QED — cold atoms coupled to nanofibers and nanophotonic waveguides for super-radiance, photon-bound states, and atom-photon gates; (3) Quantum network protocols — entanglement distribution, quantum repeater segments; part of European Quantum Flagship 'Quantum Internet Alliance'; (4) Hybrid entanglement — continuous-variable and discrete-variable hybrid entanglement for CHSH Bell tests (PRA 2024). Senior IUF member.

Department(s)/lab(s): Physics / LKB | Quantum Networks Group (Laurat Lab) @ ENS Paris
Summary:

Julien Laurat's quantum networks group develops atomic interfaces for long-distance quantum communication and sensing. Research: (1) cold atom quantum memory using DLCZ-protocol and EIT — multi-mode storage, entanglement generation; (2) nanofibre-trapped atom light interface for quantum networks; (3) quantum memory for telecom-band photons using rare-earth crystals. CNRS Silver Medal 2026. ERC Consolidator grant. Highly relevant to quantum sensing via atomic sensors and quantum network nodes.

Department(s)/lab(s): Applied Physics | Mabuchi Lab @ Stanford
Summary:

Mabuchi's group studies continuous quantum measurement and feedback in cavity-QED and photonic circuit platforms, developing the theory and hardware for real-time quantum-limited monitoring and control of light-matter systems, foundational to many quantum-sensing readout schemes.

Department(s)/lab(s): Physics / Niels Bohr Institute | Quantum Metrology Group (Müller Lab) @ UCPH
Summary:

Jörg Müller's Quantum Metrology group works on next-generation optical atomic clocks and superradiant lasers. Key experiments: cold strontium continuous superradiant laser (subnatural linewidth, pushing beyond traditional clock limitations); microresonator-based frequency combs; ultra-stable optical reference cavities; and cavity QED many-atom systems for clocks and sensing. The group is part of the EU iqClock project targeting operational optical lattice clocks.

Department(s)/lab(s): Physics – Institute for Quantum Electronics | Nanoscale Quantum Optics Group (Murthy) @ ETH Zurich
Summary:

Murthy leads the Nanoscale Quantum Optics group at ETH, studying light-matter interactions in nanostructures to engineer novel quantum states of light. Research directions: (1) Photon-photon interactions — achieving strong effective photon-photon interactions via coupling to quantum emitters in 2D materials and optical nanocavities; exploring photonic Mott insulators and collective quantum phases of light; (2) 2D semiconductor quantum emitters — localized excitons in TMD heterostructures as sources of single photons and entangled photon pairs; (3) Quantum light from cavities — engineering photon statistics and squeezing using cavity-QED with 2D materials; (4) Ultrafast quantum optics — attosecond-scale probing of light-matter entanglement. New group as of ~2023.