Many-body non-classical signatures in cold atoms fluorescence

Abstract

The access to non-classical processes in many-body systems is a challenge that intrigues both theorists and experimentalists. Even if the realization of such phenomena is possible from a technological-experimental point of view, there are still few theoretical predictions guiding such experiments. The situation worsens when the quantum dynamics of many particles is out-of-equilibrium, as the associated Hilbert space grows exponentially with the number of degrees of freedom. This makes exact numerical simulations completely infeasible and motivates the search for new approaches. In the context of light scattering by a single atom, light fluorescence has successfully connected theory and experiments. Non-classical phenomena, such as the appearance of side bands in the radiation spectrum (the Mollow triplet) and photon antibuching, were predicted in the radiation field coherences and successfully corroborated. In a cloud with many atoms, real and virtual photons give rise to short- and long-range interactions between the dipoles. In the diluted regime, the long-range terms prevail which allows the emergence of cooperative modes in the system. The present project aims to reveal many-body quantum correlations through light fluorescence emitted by cold and dilute atomic clouds. Cooperative corrections of the Mollow triplet and photon antibuching must arise, as well as the competition between superradiance and long-range dipole blockage. Many-body non-classical signatures are expected to be obtained by resummation of diagrams in the coherences of the radiation field. This methodology is extracted from quantum field theory and little used in quantum optics community, therefore, it is believed that such fusion will result in a research line not yet explored in Brazil. The results will be confronted with experiments in São Carlos - SP and will boost the development of quantum sensors with ultra-cold atoms.