Starts 27 Sep 2016 14:00
Ends 27 Sep 2016 15:00
Central European Time
One dimensional (1D) strongly correlated quantum systems are nowadays the subject of intense theoretical and experimental activity due to the incredible experimental control offered by ultra-cold atoms setups. In such systems, the momentum distribution is a powerful probe of both gas statistics and of the intertwined effect of interactions between particles and the effective dimensionality they move in. A remarkable momentum distribution feature, in all dimensions, is the presence of universal power-law tails n(k)~k^{-4} for a gas where interactions can be schematized as contact ones (as it is the case for most standard cold gases experiments). The weight of such tails, denoted as Tan’s contact, can be put into relation with several many-body quantities, ranging from the interaction energy to the depletion rate by inelastic collisions. In this work, we show that such tails also encode precious information about the permutational symmetry hiding behind the formation of magnetic-like structures in strongly-interacting multi-component Fermi gases.

More in details, we combine an exact solution at infinite interactions and numerical Matrix-Product-State (MPS) simulations at finite interactions, in order to predict the behavior of the momentum distribution tails for a mixture of k fermionic components under 1D harmonic confinement and interacting among each other with completely SU(k)-symmetric repulsive contact interactions. We show that both the ground and excited states of the system have a well defined symmetry, thus indicating magnetic-like properties of the mixture, and that such information is fully encoded in the Tan’s contact.