"Cavity microscope for local control of atom-cavity interactions"
Francesca Orsi
Institute of Physics and Center for Quantum Science and Engineering, EPFL, Lausanne (Switzerland)

Cavity quantum electrodynamics studies the strong interaction between matter and the electromagnetic field of an optical cavity: the enhanced interaction is useful both for reading the properties of the atoms with a fast, sensitive and weakly destructive measurement and for quantum simulation where atoms interact by exchanging photons with each other at a distance. One of the drawbacks of these systems is the loss of spatial information that cavity-based measurement implies: the result of these measurements is an average of the properties of the atoms over the entire cavity field volume. I will explain how we built and operated a cavity-microscope device that overcomes this problem: it realizes both a cavity and a pair of high numerical-aperture lenses in a single device and can be used to couple a microscopic part of the atomic cloud to the cavity field [1]. We produce a cavity-based image of the atomic density by scanning the position of the microscope focus. This technology opens the doors to analog quantum simulations of programmable, all-to-all interacting systems. I will report about optical techniques to randomize cavity-mediated interactions [2]. These interactions can drastically change the behavior of the system, and open the door to the exploration of models of holographic quantum matter such as the Sachdev-Ye-Kitaev model.

[1] Orsi, F., Sauerwein, N., Bhatt, R.P et al., Cavity microscope for micrometer-scale control of atom-photon interactions, PRX Quantum 5 (2024)

[2] Sauerwein, N., Orsi, F., Uhrich, P. et al. Engineering random spin models with atoms in a high-finesse cavity, Nat. Phys. 19, 1128 (2023)