Low-temperature atomic systems manifest behavior that is strikingly different from classical physics. In quantum mechanics, discrete energy levels underpin the current definition of the second and enable the operation of atomic clocks. As optical clocks reach ever lower uncertainties, the limiting physics is no longer only single-atom quantum mechanics: many-body correlations, interactions and collective effects can become relevant.
This laboratory develops theoretical and computational tools to analyze quantum many-body systems connected to time and frequency metrology and to quantum technologies. When problems go beyond mean-field or perturbative treatments, accurate modeling often requires massively parallel computation on High-Performance Computing (HPC) resources.
Research topics include interacting ultracold gases, quantum optics, impurity problems and spin models relevant to quantum simulation and to the interpretation of precision experiments. The work provides quantitative predictions, uncertainty estimates and data-analysis support for experiments in the Sector, helping identify systematic effects and performance limits.
Optical clocks and atom-based sensors increasingly operate in regimes where entanglement, collisions and collective dynamics affect both stability and accuracy. Theoretical modeling helps determine when these effects can be treated as small corrections and when they must be engineered or exploited, for example to achieve quantum-enhanced performance.
The laboratory also contributes to method development (efficient numerical algorithms such as stochastic quantum Monte Carlo or variational approaches) so that realistic experimental parameters can be simulated. Close interaction with experimental groups allows theory to guide measurement strategies and to interpret results, including the identification of signatures of non-equilibrium dynamics.
This way, quantum many-body theory becomes an enabling capability for both precision metrology and quantum-technology applications pursued within the Time and Frequency Sector.