This report addresses topics and questions of common interest in the fields of ultra-cold
gases and nuclear physics in the context of the BCS–BEC crossover. By this crossover, the …

In this review, we discuss the properties of a few impurity atoms immersed in a gas of
ultracold fermions—the so-called Fermi polaron problem. On one hand, this many-body …

The crossover from weak-coupling Bardeen-Cooper-Schrieffer (BCS) pairing to a Bose-
Einstein condensate (BEC) of tightly bound pairs, as a function of the attractive interaction in …

We study the thermal evolution of a highly spin-imbalanced, homogeneous Fermi gas with
unitarity limited interactions, from a Fermi liquid of polarons at low temperatures to a …

We derive exact general relations between various observables for N spin-1/2 fermions with
zero-range or short-range interactions, in continuous space or on a lattice, in two or three …

Many-body fermion systems are important in many branches of physics, including
condensed matter, nuclear, and now cold atom physics. In many cases, the interactions …

We measure radio frequency (rf) spectra of the homogeneous unitary Fermi gas at
temperatures ranging from the Boltzmann regime through quantum degeneracy and across …

A light impurity in a Fermi sea undergoes a transition from a polaron to a molecule for
increasing interaction. We develop a method to compute the spectral functions of the …

We theoretically analyze inverse radio-frequency (rf) spectroscopy experiments in two-
component Fermi gases. We consider a small number of impurity atoms interacting strongly …

We analyze the properties of a single impurity immersed in a Fermi sea. At positive energy
and scattering lengths, we show that the system possesses a well-defined but metastable …