Seminarium Optyczne

Interacting spin-boson models provide the foundational framework for exploring strong light-matter interactions across various platforms, such as atoms in optical cavities, superconducting circuits, and trapped ions. In the strongly interacting scenario, where both spin-spin and spin-boson correlations become critical to the underlying physics, standard mean-field treatments fundamentally fail. To tackle this problem, we develop a theoretical framework that goes beyond mean-field limits to accurately capture the closed-system dynamics. Applying this framework we uncover new phenomena, such as an intermediated coexisting phase where strong spin-spin and spin-photon correlations enhance the superradiant response. In the open-system scenario, we apply a distinct but related approach, which is particularly aligned with realistic setups like Rydberg atoms in optical cavities, in the fast-cavity limit, where the far-detuned cavity acts as a mediator of spin interactions. Finally, the effective spin Hamiltonians that arise from virtual photon exchange in this regime are shown to lead to highly efficient spin squeezing generation.