STAGE Quantum magnetism of ultracold fermions in optical lattices

Date de mise à jour de l’offre

Laboratoire de physique des lasers :

Le Laboratoire de Physique des Lasers est une Unité Mixte de Recherche du CNRS Logo CNRS (UMR 7538) et de l'Université Sorbonne Paris Nord (anciennement Université Paris 13)Université Sorbonne Paris Nord. Nous étudions les interactions entre la lumière et la matière. Nos expériences vont des domaines les plus fondamentaux à la recherche appliquée : physique quantique, atomique et moléculaire, dispositifs photoniques, optique biomédicale... Les thématiques scientifiques du laboratoire s'étendent jusqu'aux interfaces avec la chimie, la biologie et les nanotechnologies. La recherche au laboratoire est structurée en cinq axes et elle bénéficie du soutien de cinq services généraux. Il est constitué d’environ quatre-vingts personnes (10 chercheurs C.N.R.S., 30 enseignants-chercheurs, 15 personnels techniques, plus de 25 doctorants et post-doctorants) auxquelles s’ajoutent des stagiaires et des visiteurs étrangers.

Description de la mission

We offer an experimental internship in the field of ultracold atoms. Our research topic is
quantum magnetism, i.e., the collective behavior of ensembles of interacting spin-carrying
particles. We experiment on ensembles of strontium atoms, arranged on a periodic structure
created by interfering laser beams: an optical lattice potential. Our aim is to study the
conditions for the emergence of antiferromagnetic ordering. We will be able to realize
situations analogous to those encountered by electrons (of spin ½) in crystalline materials, but
also situations that strongly contrast with those, as a consequence of the spin 9/2 of our atomic
species. For studies of magnetism, atomic physics offers an interesting new set of tools; in
particular, the narrow lines of Sr, of use to atomic clocks, will be exploited in original
protocols to prepare alternating-spin textures and thus study the low-energy behavior of our
system.
Our experiment produces since 2019 degenerate fermionic quantum gases of 87Sr. We are
presently building the optical lattice, such that our system will realize the antiferromagnetic
Heisenberg Hamiltonian. The internship project, and its extension into a PhD thesis, will be
the following:
- The intern will be responsible for installing a high-resolution imaging system (~1.2 μm)
orthogonal to the lattice planes. A homemade mechanical support with fine position and angle
adjustments, required for aberration-free imaging, will be designed and built.
- The intern will contribute to loading the sample in the optical lattice. The first objective will
be to load the ground Bloch band. The imaging system will enable measurements of the
quasi-momentum distribution. We aim at reaching two distinct physical regimes: the band
insulator, with a sample polarized in a single spin state; and the Mott insulator ensured by
interactions, with an unpolarized sample.
If the progresses allow it, we will start the implementation of our protocols for preparing lowenergy
spin textures, that relies on a laser system already built. The response of the sample to
these manipulations, e.g. their degree of reversibility, will provide insight into the low-energy
magnetic properties of the system.

Profil recherché

The project is built in strong connection with a second experiment in our group (quantum
magnetism with dipolar chromium atoms), and a theory activity in our group (P. Pedri) and at
ENS Lyon (T. Roscilde). The internship will provide an introduction to the essential
experimental tool of cold atom experiments (lasers, optics, optomechanics, electronics), and
will include an important part of team work on the setup that produces the degenerate gases.
This work can act as an introduction to a PhD thesis on the Sr experiment. In September 2021,
the new PhD student will work with a 3rd-year PhD student, and two permanent researchers
on the Sr experiment.

Niveau de qualification requis

Bac + 4/5 et +
  • Employeur
    Laboratoire de physique des lasers
  • Secteur d’activité de la structure
    Enseignement - Formation - Recherche
  • Effectif de la structure
    De 51 à 250 salariés
  • Site internet de la structure
    http://www-lpl.univ-paris13.fr
  • Type de stage ou contrat
    Stage pour lycéens et étudiants en formation initiale
  • Date prévisionnelle de démarrage
  • Durée du stage ou contrat
    Plus de 4 mois et jusqu'à 6 mois
  • Le stage est-il rémunéré ?
    Oui
  • Niveau de qualification requis

    Bac + 4/5 et +
  • Lieu du stage
    99, avenue Jean-Baptiste Clément
    93430 VILLETANEUSE
  • Accès et transports
    http://www-lpl.univ-paris13.fr/FR/Venir-au-LPL.awp