Low-temperature atomic systems manifest phenomena that are strikingly different from classical mechanics. Quantum mechanics implies that energy levels are discrete and this is the foundation of the current definition of the second.

Accuracy and precision of optical clocks are entering a regime where not only single-atom quantum mechanics is crucial, but also quantum many-body phenomena play a relevant role. When going beyond mean-field or perturbative theoretical approaches, their study generically requires massively parallel computation on HPC resources.

We are presently investigating:

- the role of ultracold atomic collisions in optical atomic clocks, to improve their accuracy, by means of quantum Monte Carlo methods;

- the dynamics of ultracold atoms in an optical cavity, as a means to engineer collective behavior for better clock precision, by means of quantum dynamics libraries such as QuTip and novel quantum Monte Carlo methods;

- the equation of state of trapped ultracold Fermi and Bose gas mixtures