Large quantum systems, such as Bose-Einstein condensates (BEC) where many bosonic particles collectively behave as a single quantum object, are powerful experimental tools for advancing our knowledge of quantum physics and enabling applications surpassing the limits of technology relying on classical physics. For example, BECs made of atoms have led the way in testing theories and found applications in quantum simulations and metrology. However, atomic BECs can only operate in ultracold environments (~ nK) requiring complex vacuum and cooling systems, hindering compact device designs for practical and scalable deployments.

Promising alternative particles for harnessing many-body quantum states are exciton polaritons – hybrid light-matter quasiparticles in a semiconductor microcavity. They can form a BEC but in a semiconductor device at high temperatures (> 300 K), enabling integration of BECs onto chips for large-scale implementation and electrical injection. This makes polaritons a unique and versatile platform for on-chip generation of quantum sources for integrated quantum technologies. As hybrid light-matter system, polaritons also offer a unique platform in bridging matter-based and light-based quantum technologies.

This project aims to measure the quantum properties of polaritons by probing continuous variables of the emitted light (as the polariton decay. The project will provide foundational experiments of quantum polaritonics, which will pave the way for applications, such as quantum light generation on a chip. Potential experiments include quantum state tomography of polariton condensates, detection and control of squeezing, and generation of more complex quantum states, such as non-Gaussian states and spin squeezing.