Casimir-polder Interaction Control of Cold Atoms

**Casimir-Polder interaction control of cold atoms and nano devices for fundamental physics**:

- Réf **ABG-125773**
- Sujet de Thèse- 11/09/2024- Autre financement public- Laboratoire de Physique des Lasers- Lieu de travail- Villetaneuse - Ile-de-France - France- Intitulé du sujet- Casimir-Polder interaction control of cold atoms and nano devices for fundamental physics- Champs scientifiques- Physique
- Mots clés- experimental physic, Casimir-Polder, cold atoms, fundamental physics**Description du sujet**:

- A striking feature of quantum mechanics is the possibility of energy change E during a time t due to the Heisenberg principle ( E t ħ/2). It leads to quantum fluctuations that create virtual photons and generate a quantized field. In particular, the presence of boundaries, given for example by a surface and an atom, modifies this field. It results in a force between the surface and the atom, known as the Casimir-Polder (C-P) force. This force becomes preponderant at the nanoscale and thus plays a major role in a multitude of areas of Physics, ranging from atomic physic to** **theoretical fundamental physics such as the 5th force and accurate gravity measurement.- Despite its simplicity, combined with strong scientific and technological interests, C-P interaction, at its fundamental level, remains largely unexplored mainly due to challenges associated with precise control of the atom-surface distance and knowledge of the surface characterization. In this context, our team_ _has built a slow atomic beam interacting with a nanograting [1,2]. This jet interacts with a carefully self-engineered nanograting, leading to a diffraction pattern dominated by the C-P force. This unique configuration allows us to study precisely the C-P interaction.- The current interest of the experiment is to achieve an in-depth understanding of the C-P interaction. To achieve this goal, the successful applicant will take an active role in various aspects of the experiment including **data acquisition, data analysis**, the development of tools for characterizing the atomic source, and the installation of an **optical dipole trap** (to increase the atomic flux and reduce the atomic velocity). Additionally, the internship has as well a **theoretical component with the description of the interference figure and quantum electrodynamic calculations**. There will also be a clean-room aspect to the project, involving work on the generation of new nanogratings. The short term goal of the project is to tailor the C-P interaction using material geometries. In the medium term, this work will open the door to study eventual modifications of the Newtonian gravitational interaction at short range, where C-P interaction shields such forces.- The successful applicant will work as a fully integrated team member. The PhD encompasses various components, including experimental work, cleaning room activities, and theoretical studies.- [1] C. Garcion, et al. _Phys. Rev. Lett_. **127**, 170402 (2021).- [2] J. Lecoffre et al, _arXiv:2407.14077_ (2024).**Prise de fonction**:

- 01/09/2025**Nature du financement**:

- Autre financement public**Précisions sur le financement**:

- ANR**Présentation établissement et labo d'accueil**:

- Laboratoire de Physique des LasersLe Laboratoire de Physique des Lasers est une Unité Mixte de Recherche du CNRS (UMR 7538) et de l’Université Sorbonne Paris Nord (anciennement Université Paris 13). La recherche au laboratoire est structurée en cinq axes et elle bénéficie du soutien de cinq services généraux.

L’équipe OIA réalise au moyen de jets d’atomes métastables froids diffusés par des surfaces, des expériences d’optique et d’interférométrie atomiques.

**Intitulé du doctorat**:

- Doctorat de Physique**Pays d'obtention du doctorat**:

- France**Etablissement délivrant le doctorat**:

- Université Paris Sorbonne Nord