Our very own Xin and Eugen, together with Emilio and Richard have a new preprint on arXiv!

They address a long-standing challenge in quantum many-body physics: unifying the quasiparticle description of Fermi polarons with Anderson’s orthogonality catastrophe. They show that impurity recoil naturally introduces a mass gap in the fermionic dispersion, which explains the power-law decay of quasiparticle weights and the emergence of the polaron-to-molecule transition. This universal mechanism bridges the conceptual divide between mobile and static impurities, offering a coherent framework for understanding various phenomena. Its universal nature and predictive power make it broadly relevant for ultracold-atom experiments and condensed-matter systems.

New preprint: Mass-gap description of heavy impurities in Fermi gases

• Xin Chen, Eugen Dizer, Emilio Ramos Rodríguez, Richard Schmidt, Mass-gap description of heavy impurities in Fermi gases, [arXiv:2507.15957](2025).