Experiments

Welcome to Tarik Yefsah Labs

Our group studies the physics of ultracold Fermi gases in a regime where the interplay between interactions and quantum statistics gives rise to strong correlations between particles. At low temperature, the collective behavior of these interacting particles leads to dramatic effects, such as superfluidity, the analog for neutral particles of superconductivity. While strongly correlated Fermi systems are ubiquitous in Nature and modern materials, they are notoriously difficult to tackle theoretically. Our group aims at understanding the behavior of strongly-interacting fermionic systems using an atom-based quantum simulator featuring single-atom imaging and manipulation capabilities. 

Learn more on our group webpage here.

Quantum Gas Microscopy of Fermions in the Continuum

Microscopically probing quantum many-body systems by resolving their constituent particles is essential for understanding quantum matter. In most physical systems, distinguishing individual particles, such as electrons in solids, or neutrons and quarks in neutron stars, is impossible. Atom-based quantum simulators offer a unique platform that enables the imaging of each particle in a many-body system. Until now, however, this capability has been limited to quantum systems in discretized space such as optical lattices and tweezers, where spatial degrees of freedom are quantized. Here, we introduce a novel method for imaging atomic quantum many-body systems in the continuum, allowing for in situ resolution of every particle. We demonstrate the capabilities of our approach on a two-dimensional atomic Fermi gas. We probe the density correlation functions, resolving their full spatial functional form, and reveal the shape of the Fermi hole arising from Pauli exclusion as a function of temperature. Our method opens the door to probing strongly-correlated quantum gases in the continuum with unprecedented spatial resolution, providing in situ access to spatially resolved correlation functions of arbitrarily high order across the entire system.

Tim de Jongh, Joris Verstraten, Maxime Dixmerias, Cyprien Daix, Bruno Peaudecerf, and Tarik Yefsah arXiv:2411.08776 (2024)

See related works from the Zwierlein group and Ketterle group 

In-situ Imaging of a Single-Atom Wave Packet in Continuous Space

The wave nature of matter remains one of the most striking aspects of quantum mechanics. Since its inception, a wealth of experiments has demonstrated the interference, diffraction or scattering of massive particles. More recently, experiments with ever increasing control and resolution have allowed imaging the wavefunction of individual atoms. Here, we use quantum gas microscopy to image the in-situ spatial distribution of deterministically prepared single-atom wave packets as they expand in a plane. We achieve this by controllably projecting the expanding wavefunction onto the sites of a deep optical lattice and subsequently performing single-atom imaging. The protocol established here for imaging extended wave packets via quantum gas microscopy is readily applicable to the wavefunction of interacting many-body systems in continuous space, promising a direct access to their microscopic properties, including spatial correlation functions up to high order and large distances.


Joris Verstraten, Kunlun Dai, Maxime Dixmerias, Bruno Peaudecerf, Tim de Jongh, and Tarik Yefsah arXiv:2404.05699 (2024)

Featured in : 1) NewScientist​ 2) LiveScience 3) IFLScience 4) NewScientist Netherlands