Quantum Science Colloquium - Jean-Philippe Brantut, EPFL – Laboratory for Quantum Gases, Lausanne
Oplysninger om arrangementet
Title: Exploring quantum matter with atoms and photons
Cavity quantum electrodynamics (QED) is one of the most powerful framework to observe and leverage quantum phenomena. While it has been thoroughly studied for simple quantum systems such as two-level systems or harmonic oscillators, it has only recently become available for complex, correlated quantum many-body systems. In the last five years, we have developed systems combining cavity QED with Fermi gases. After describing this system, I will present the use of the cavity to engineer long-range interactions between Fermions or between spins encoded atoms. In a first experiment, we realize a doubly-tunable Fermi gas, with strong contact interactions and strong long-range, photon mediated interactions. This system exhibits superfluidity without long-range interactions and a density-wave order above a critical long-range interaction strength, opening a new window into the complex interplay of phases in quantum matter. In a second experiment, we realize an all-to-all connected quantum magnet and study the competition between ferromagnetism and a controlled disorder, by controlling locally the spatial structure of light-matter interaction. This opens the perspective to engineer of arbitrary strength and range of interactions in quantum gases.