Title of seminar: Présentation sur l’Ecole Doctorale, ses actions, ses missions, le déroulement du doctorat, etc…

Abstract:

C’est aussi et surtout un moment où nous allons essayer de favoriser les échanges, sur les rôles du CSI, des formations, etc…

Title of seminar: A cavity-coupled Rydberg array for error-corrected quantum computing

Abstract:

Scalable quantum computers and quantum networks require the combination of quantum processing nodes with efficient light-matter interfaces to distribute quantum information within local or long-distance quantum networks. Neutral atoms in optical tweezer arrays have become a leading platform for these applications. We leverage recent developments to realize a novel experiment that strongly couples a rubidium atom array to a high-finesse optical resonator.
I will present our compact and versatile setup, our ability to trap, detect, and manipulate individual rubidium atoms in optical tweezers and couple them strongly to the optical mode of a high-finesse optical cavity. I will also report on our first two-qubit gates mediated by Rydberg interaction. This platform enables fast, high-fidelity control and readout, and opens routes toward cyclic error correction with real-time feedback, remote entanglement generation within and between atom arrays, and the quantum simulation of open-system dynamics.

Title of seminar: Quantum logic control of molecular and transition-metal ions

Abstract:

Quantum metrology exploits uniquely quantum properties such as entanglement and quantum interference to improve the precision of measurements beyond what is achievable with classical resources. While quantum-enhanced sensing has demonstrated remarkable performances in laboratory environments, transferring these advantages to practical fiber-based platforms remains a significant challenge due to optical losses and experimental imperfections.

In this seminar, I will present our recent work on quantum interferometric metrology using entangled photons in telecom optical fibers. After introducing the concepts of quantum advantage and a Fisher information framework for realistic quantum sensing, I will present the experimental demonstration of quantum-enhanced phase sensing in an all-fiber Mach–Zehnder interferometer. These results illustrate the potential of fiber-integrated quantum photonics for practical quantum sensing. Then, I will introduce our recent work on quantum-enhanced phase tracking through spectral noise reduction and finally discuss how quantum communication techniques, including QKD-based synchronization, can be leveraged to enable long-distance quantum sensor networks.

The seminar will illustrate how quantum photonic technologies are progressively moving from proof-of-principle demonstrations toward practical quantum sensing systems compatible with existing telecommunication infrastructures.

Title of seminar: Quantum logic control of molecular and transition-metal ions

Abstract:

Extending quantum control to increasingly complex systems is essential for advancing quantum technologies and probing fundamental physics. Molecules, in particular, serve as highly sensitive systems for detecting symmetry violations that may reveal physics beyond the Standard Model. However, their complex level structure makes quantum-state control challenging.

Quantum logic spectroscopy offers a promising path forward for molecular ions: a well-controlled atomic ion is co-trapped with a molecular ion and enables manipulation and readout of its quantum state via shared motional modes. I will present an overview of our latest results and concepts in quantum logic control of molecular ions. As we progress toward quantum logic spectroscopy of single molecular MgH⁺ ions, we are also assessing the broader applicability of these techniques to other ionic species. Recently, we demonstrated quantum logic control of a single titanium ion [1,2], showing that these methods can be extended to previously inaccessible atomic systems.

By enhancing control over new classes of ions, our work opens the door to novel applications in quantum technology and fundamental physics, making an extended range of species available for precision spectroscopy.

References:

[1] Rehmert et al. Quantum Logic Control of a Transition Metal Ion, Physical Review Letters 134, 113201 (2025)

[2] Rehmert et al. Landé g Factor Measurement of ⁴⁸Ti⁺ Using Simultaneous Comagnetometry and Quantum Logic Spectroscopy, Physical Review Letters 136, 083203 (2026)