Quasiparticles - wholes in the Fermi sea

Imagine a particle flying through a dense gas, interacting with the particles of that gas. Due to the interaction the particle will experience dissipation and fluctuation. Both effects will typically increase as the density goes to infinity.

While this is true for a classical gas and also for Bose gases, the behaviour is very different for gases of Fermions: A charged particle moving through a Fermi sea of high density behaves almost like a free particle.

Here the Fermi pressure leads to a suppression of the fluctuations in the gas and eventually a suppression of fluctuation and dissipation.

While this is easy to prove in one dimension, the two dimensional case is highly non trivial. I will present recent results on this question.