AMO Seminar: Hadrien Kurkjian, Laboratoire de Physique Théorique de Toulouse, “Excitation spectrum of fermionic condensates”

Event time: 
Wednesday, May 24, 2023 - 2:00pm to 3:00pm
Sloane Physics Laboratory SPL, Room 51 See map
217 Prospect Street
New Haven, CT 06511
Hadrien Kurkjian, Laboratoire de Physique Théorique de Toulouse
Event description: 

Unlike their bosonic counterparts, fermionic condensates (such as superconductors, superfluid Helium 3 or two-component Fermi gases) are made of composite objects: the Cooper pairs. This underlying composite structure gives them a rich excitation spectrum: besides the phononic (in neutral systems) or plasmonic branch (in charged systems) of density excitations, fermionic condensates support a collective branch corresponding to a vibration of the binding energy of the Cooper pairs. At low temperature, this mode (sometimes reductively called a Higgs mode) can be observed with ultracold gases by tuning the interaction strength, and tracking the decaying oscillations of the order parameter. Near the critical temperature, the mode evolves into a low-energy pairing mode of quadratic dispersion, which (above Tc) acts as a precusor of the phase transition.
Host: Nir Navon (