• thermal radiation
• quantum simulator
• Rydberg atoms

Ultracold Rydberg atoms are turning out to be an excellent framework to implement quantum simulators. The presence of dissipation, which is naturally implemented in Rydberg atoms through pontaneous decay and thermal radiation-induced transitions, permits to simulate out of equilibrium systems.
In a typical ultracold atoms apparatus like ours, the hypotheses that underlies the Planck formula are not satisfied. It is important to characterize the actual thermal radiation spectrum, in order to know and eventually control the form of the dissipation in simulations.
In my thesis I implemented simulations for the Rydberg states lifetimes which take into account an arbitrary modification of the thermal radiation spectrum with respect to Planck's formula.
To characterize the microwave spectrum, I measured the microwave intensity seen by the atoms (which depends on the mode structure inside the apparatus), exploiting AC Stark shift.
However, for physical reasons I explain in my thesis, we were not able to normalize the measured intensity with the incident power.
Without this normalization, we can't reconstruct quantitatively the form of the thermal radiation spectrum. We can still observe how the position of some additional electrodes near the atoms causes the appearance or disappearance of some resonances in the spectrum. Some possible solutions to overcome the normalization problem and reach the goal of reconstructing the exact form of the thermal radiation spectrum are proposed.