University of the State of Rio de Janeiro.
«Nematic fluctuations and exceptional points in Fermi liquids»
Fermi liquid theory successfully describes the low-energy properties of most metals. However, higher angular momentum interactions, such as quadrupolar couplings, reveal unexpectedly rich collective behavior. In this seminar, I will analyze collective excitations in a two-dimensional Fermi liquid with quadrupolar interactions.
Our main result is the discovery of a dynamical phase transition, marked by the sudden appearance or disappearance of stable collective modes. At a critical attractive coupling, two stable modes coalesce into a single damped mode, a singularity identified as an exceptional point.
I will characterize this singularity, discuss its topological properties, and present experimental signatures. These findings open new perspectives on dissipative collective dynamics in Fermi liquids and may be relevant to nematic fluctuations in cuprates, iron-based superconductors, and ultracold Fermi gases.