Description du sujet de thèse

The NS2 group developed an activity linking quantum transport and plasmonics. We have investigated the emission mechanism of photons from a tunnel junction and established a quantitative relationship between the emitted light power and current fluctuations at optical frequencies. Although this allowed us to measure tunneling time directly1, it turns out that inelastic processes excite surface plasmons before emitting photons. Understanding the correlations between the current and the photons emitted by inelastic electron tunneling is crucial for the electrical control of photon emission. In order to measure such correlations, we have to measure plasmons directly.

To that purpose, we are developing an on-chip surface plasmon detector based on kinetic inductance technology. With this detector, we aim to explore correlations between current and radiative decaying plasmons, analogous to the third moment of current fluctuations at optical frequencies. From a more fundamental point of view, this also raises a basic question related to the quantum detection theory: is a radiofrequency electronic measurement equivalent to a photo-detection measurement2? The objectives are to address several questions of fundamental interest including a possible back action in the presence of high-Q optical modes onto the junctions or even cross-correlations between several junctions coupled to the same optical bath. The experimental work will be supported by theoretical input from the University of Marseille developing a new theoretical framework based on the Non-Equilibrium Green's Function for investigating IET.

The candidate must have a strong theoretical background in condensed matter physics and light-matter interaction, with a strong interest in nano-devices, nano-optics, and weak-signal detection.

[1] P. Février et al. Tunneling time probed by quantum shot noise. Nat. Comm. 9, 4940 (2018).
[2] J. Gabelli et al. Electron–photon correlations and the third moment of quantum noise, New J. Phys. 15 113045 (2013)

Contexte de travail

The Laboratoire de Physique des Solides (LPS) is a joint research unit (UMR 8502) affiliated with Université Paris-Saclay and the French National Center for Scientific Research (CNRS). It is part of the CNRS Physics Institute and associated with section 28 of the National Council of Universities (CNU). The LPS is also a member of the Friedel-Jacquinot Federation, a coordination structure for physics research on the Moulon campus in Orsay, Île-de-France.

The laboratory hosts around one hundred researchers and faculty members—both experimentalists and theorists—and its research activities are supported by approximately sixty engineers, technicians, and administrative staff. Each year, LPS welcomes a large number of undergraduate and graduate students, including many PhD candidates, as well as postdoctoral researchers and visiting scientists.

Despite its name, the Laboratoire de Physique des Solides covers a much broader range of topics and aims to address the full diversity of condensed matter physics. Research at LPS is structured around three main scientific themes, each involving roughly the same number of researchers:

Novel Electronic States of Matter

Physical Phenomena at Reduced Dimensions

Soft Matter and the Physics–Biology Interface

The first axis includes both theoretical and experimental studies of systems where electronic correlations play a dominant role, often giving rise to remarkable properties and unconventional electronic states such as superconductivity, magnetism, and metal–insulator transitions.

The second axis encompasses activities related to nanoscience in the broad sense, focusing on fundamental properties that emerge when the dimensions of an object approach characteristic physical length scales (e.g., coherence length, mean free path, etc.).

The third axis extends the concept of soft matter to biological systems, covering topics ranging from complex systems to living tissues, liquid crystals to foams, and including polymers and granular materials. These studies lie at the intersection of physics, physical chemistry, and biology.
The research work will take place within the NS2 team at the Laboratoire de Physique des Solides (CNRS–UMR 8502). This PhD project is funded by the French National Research Agency (ANR).

Informations complémentaires

The candidate must have a strong theoretical background in condensed matter physics and light-matter interaction, with a strong interest in nano-devices, nano-optics, and weak-signal detection.