Colloques du Collège de France - Collège de France

Pascale Senellart
Chaire annuelle Innovation technologique Liliane Bettencourt (2025-2026)
Collège de France
Année 2025-2026

Colloque : Light-based Quantum Technologies
Pascale Senellart, chaire Innovation technologique Liliane Bettencourt

Colloque - Hugo Defienne : Quantum Imaging with Entangled Photons

Résumé

Entanglement stands as a foundational resource in quantum technologies. Lacking a classical equivalent, it theoretically guarantees superior performance over classical systems, provided it plays a non-trivial role in the underlying process. However, in the field of optical imaging, demonstrating the indispensable nature of entanglement remains a significant challenge. Most current applications rely on optical correlations derived from entangled states - features that can often be emulated by classical sources - rendering entanglement a sufficient, rather than strictly necessary, component.

In this presentation, we explore imaging scenarios where entanglement becomes a critical and non-trivial asset. Specifically, I will discuss recent experimental studies utilizing entangled photon states to image through scattering media, highlighting regimes where quantum entanglement provides a definitive advantage over classical alternatives. And, as a nod to the foundations of quantum mechanics, the presentation will be illustrated with the mandatory pictures of cats!

Hugo Defienne

Hugo Defienne's research focuses on quantum optics, imaging, and complex media. He is a researcher at the CNRS at Sorbonne University in Paris, where he heads the Quantum Imaging Paris group. He completed his doctoral thesis at the Kastler-Brossel Laboratory in Paris, where he studied quantum optics in disordered media. He graduated in 2016 and then turned his attention to quantum imaging in his postdoctoral research at Princeton University and then at the University of Glasgow. He became a lecturer in Glasgow before returning to Paris in 2022 to set up his own group at the CNRS thanks to a grant awarded to early-career scientists by the European Research Council.

Pascale Senellart
Chaire annuelle Innovation technologique Liliane Bettencourt (2025-2026)
Collège de France
Année 2025-2026

Colloque : Light-based Quantum Technologies
Pascale Senellart, chaire Innovation technologique Liliane Bettencourt

Colloque - Anaïs Dréau : Single Color Centers for Silicon-Based Quantum Technologies

Anaïs Dréau

Résumé

Capitalizing on the success of the microelectronics and integrated photonics industries, silicon is the material that has generated the most scientific interest for quantum technologies and offers currently the greatest diversity of integrated quantum systems. Recently, in 2020, a new type of physical systems in silicon has emerged for quantum applications: individual color centers. These fluorescent point defects can be isolated at single defect-scale using low-temperature confocal microscopy, and emit single photons directly at telecom wavelengths, suitable for long-distance propagations in optical fibers. Furthermore, some of these defects are also coupled to an optically detectable electron spin that could be used to store and process quantum information.

Pascale Senellart
Chaire annuelle Innovation technologique Liliane Bettencourt (2025-2026)
Collège de France
Année 2025-2026

Colloque : Light-based Quantum Technologies
Pascale Senellart, chaire Innovation technologique Liliane Bettencourt

Colloque - Hugues de Riedmatten : Quantum Memories for Quantum Networks

Hugues de Riedmatten

Résumé

The distribution of entanglement between the nodes of a quantum network will allow new advances e.g. in long distance quantum communication, distributed quantum computing and quantum sensing. The realization of large-scale quantum networks—also known as quantum internet—will require quantum repeaters to enable quantum communication over distances much longer than the fiber attenuation length. The nodes of a quantum repeater are matter systems that should efficiently interact with quantum light, allow entanglement with photons (ideally at telecommunication wavelengths) and serve as a quantum memory allowing long-lived, faithful and multiplexed storage of entangled quantum bits.

Pascale Senellart
Chaire annuelle Innovation technologique Liliane Bettencourt (2025-2026)
Collège de France
Année 2025-2026

Colloque : Light-based Quantum Technologies
Pascale Senellart, chaire Innovation technologique Liliane Bettencourt

Colloque - Adriana E. Lita : Development of Superconducting Single-Photon Detectors for Quantum Information Applications

Adriana E. Lita

Résumé

Single-photon detectors are a key enabling technology for the realization of light-based quantum information applications. These devices operate at the fundamental limit of electromagnetic signal strength, which places stringent requirements on their performance. The quest for an ideal single-photon detector aims to combine as many of the following performance metrics as possible: near-unity detection efficiency, ultra-low dark count rates, fast temporal response, and photon-number-resolving capability, all across a wide spectral range.  In this presentation I will review the development and latest performance records achieved by single-photon detectors, with a focus on superconducting detectors such as Superconducting Nanowires Single-Photon Detectors (SNSPDs) and Transition-Edge Sensors (TESs). I will highlight how these detectors have redefined the state-of-the-art and conclude by showcasing representative applications in quantum information science and related fields.

Pascale Senellart
Chaire annuelle Innovation technologique Liliane Bettencourt (2025-2026)
Collège de France
Année 2025-2026

Colloque : Light-based Quantum Technologies
Pascale Senellart, chaire Innovation technologique Liliane Bettencourt

Colloque - Alexia Auffèves : An Energetic Perspective on Fundamental Processes in Quantum Optics

Alexia Auffèves

Résumé

For the emerging field of quantum energetics, a crucial motivation is to understand how quantum features impact energy and entropy exchanges in the quantum realm. Energetic footprint of quantum coherence and entanglement, irreversibility of quantum measurement and decoherence are typical research topics in the field. By staging simple interacting systems like atoms and photons, quantum optics provides a convenient scenery to study these effects. In this talk I will present a new framework to analyse energy and entropy exchanges in quantum optics, and apply it to elementary mechanisms: spontaneous and stimulated emission, coherent driving, driven-dissipative dynamics. I will showcase a few recent experimental results to illustrate the operationality of this framework before concluding on the impact of this research on the energy cost of quantum technologies.