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Dynamique quantique

Photo de l'équipe Dynamique quantique en février 2018

Membres

Permanents : Marc Cheneau, Florence Nogrette
Doctorants : Anaïs Molineri, Clémence Fréjaville, Romaric Journet

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Une place de doctorant est à pourvoir en 2020. Contactez-nous si notre ligne de recherche vous intéresse !

Recherche

Statistical mechanics, a century-old theory, is probably one of the most powerful constructions of physics. It predicts that the equilibrium properties of any system composed of a large number of particles depend only on a handful of macroscopic parameters, no matter how the particles exactly interact with each other. But the question of how many-body systems relax towards such equilibrium states remains largely unsolved. This problem is especially acute for quantum systems, which evolve in a much larger mathematical space than the classical space-time and obey non-local equations of motion. Quantum relaxation dynamics is a flourishing research topic that has undergone a paradigm change in the past decade thanks to brilliant theoretical advances. Yet experimental evidence for the new paradigm remains scarce, which prevents the topic to reach full maturity.

Our team focuses its research precisely on the dynamics of quantum gases, which serve here as a model system for generic many-body quantum systems. We are currently building a new platform to perform our experiments. The atomic species we have chosen is Strontium, which offers both bosonic and fermionic isotopes and features a versatile optical spectrum with broad, narrow and ultra-narrow lines. The atoms will be confined to a two-dimensional geometry, and subject to an optical lattice. Our set-up will implement a fluorescence microscopy imaging system enabling single-atom sensitive, single-site resolved in-situ detection of the atoms. The ability to excite the atoms to a Rydberg state shall complete our tool set for tailoring the microscopic parameters of our model system.

Our first scientific objective will be to test the universality of the 'quasi-particle scenario' put forward to explain the propagation of correlations in a quantum system brought far from equilibrium by a so-called 'quantum quench'. According to this scenario, the first times of the dynamics consists in the emission of quasi-particle excitations which then propagate across the system and spread the correlations which exist between them. It follows that something analogous to a light-cone ‑meaning a well-defined space-time region in which correlations can develop‑ should emerge and bound the dynamics. Such scenario has been numerically observed in a number of configurations, but experiments are required where numerics fails.

Dernières nouvelles

6th November 2019: Today is a great day: Anaïs Molineri defends her PhD thesis! We are lucky that she decided to stay a few more months with us after that to complete the construction of the apparatus.

25th October 2019: Our first paper is now available on the arXiv server! In this article, we present a new spectroscopy scheme for the Strontium intercombination line. The work was performed in collaboration with the Magnetic Quantum Gases team at Laboratoire de Physique des Lasers.

October 2019: We have now received pretty much all the components to build the science chamber, the optical transport, traps and lattices, and the microscopy imaging system. We have started baking the chamber. We will start assembling the whole ensemble very soon!

October 2019: Romaric offcially starts his PhD thesis this month.

April 2019: We are proud to announce our first magneto-optical trap operated on the intercombination line! We would have loved to give you some more details on the newborn, but we first have to fix the stability of our 461-nm laser system...

March 2019: During the past months we had been working in collaboration with the Magnetic Quantum Gases team at Laboratoire de Physique des Lasers on a new spectroscopy scheme for the 689-nm strontium intercombination line of. We have now finished the measurement campaign and will start wrapping up our results in a joint article.

March 2019: We welcome a new Master student in our team: Romaric Journet. Romaric studied Optical engineering at Institut d'Optique. He will assist Clémence in trapping and cooling our atoms using the 689-nm intercombination line.

June 2018: Our experiment control software is up and running. We are using a Python software developed by Christoph Gohle, Christian Groß and Sebastian Blatt at MPQ Garching. There will still be some coding to do in the coming months, but we can already automatize most of the tasks.

March 2018: First magneto-optical of Strontium atoms!!! For now it is operating on the broad transition at 461 nm and is loaded with the most abundant isotope, Strontium 88.

October 2017: After months of head scratching and drawing sketches and Florence Nogrette, helped by Anaĩs and Clémence, has spent the summer assembling the vacuum system from the Strontium oven to the MOT chamber;

October 2017: Clémence officially starts her PhD with us!

March 2017: Clémence Briosne-Fréjaville joins us for her Master insternship. Clémence studied Optical Engineering at Institut d'optique. She will devise our strategy to transport atoms form the magneto-optical trap chamber to the science chamber.

September 2016: Anaĩs Molineri engages in a PhD with us! Her first task is to build the 461 nm laser system.

May 2016: Official start of the DYNAMIQS project funded by the ERC.

March 2016: Anaĩs Molineri joins the team for the internship concluding her Master studies. She will lock the frequency of the 689 nm laser on the high-finesse optical reference cavity. The system will provide a spectrally narrow laser source to address the Strontium intercombination line.

February 2016: The optical tables have been delivered. We can finally start setting up the laser system.

October 2015: Our project has been selected by the ERC panel for funding!!

March 2015: The RySQ project is starting! Our team is one of the many partners running this EU funded project, which aims at leveraging Rydberg atoms for performing quantum simulation.

Remerciements

Since the start of the project we have formed close ties with Bruno Laburthe‑Tolra, Étienne Maréchal and Martin Robert-de-Saint-Vincent from the Laboratoire de Physique des Lasers (CNRS, University Paris 13). Their experiments reveal the magnetic properties in quantum gases of atoms with a large spin: Chromium for quite some time and most recently Strontium.

We also thank Christian Groß and Sebastian Blatt from the Max-Planck-Institute for Quantum Optics in Garching for providing us with their powerful experiment control software and with all the support to adapt the software to our needs.

Financements

This project has received funding from:

  • the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme (grant agreement number 679408 / DYNAMIQS)
  • the European Union's Horizon 2020 research and innovation programme (H2020-FETPROACT-2014 grant number 640378 / RYSQ)
  • the Balzan Prize foundation through the prize awarded to Alain Aspect in 2013
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