Study of Low Energy Excitations of Cold Atomic Fermi Systems using Quantum Monte Carlo Methods

The calculation of dynamical properties of quantum many-body theories is a big challenge from both the theoretical and computational point of view. Quantum Monte Carlo methods are considered to be some of the most accurate apporaches for unravelling physical mechanisms in systems where correlations are so strong that simple approaches are doomed to fail. Most of the success of Quantum Monte Carlo techniques involve static properties of physical systems, like phase diagrams and density correlations. The extension to dynamical quantities, like the spectrum of density fluctuations or the spectral function is still a major challenge, despite some important recent successes. Cold atomic Fermi systems are unique due to the unprecedented experimental control that can be achieved and due to the flexibility of hamiltonians that can be engineered. This makes them a unique test ground for correlated methodologies like Quantum Monte Carlo. In this presentation we will review important recent advances in the calculations, and we will present new results about the spectrum of density fluctuations and spectral functions of Fermi gases.