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Polaronic effects in superfluid Fermi gases.

When a particle is placed in a medium consisting of other quantum particles, the interaction with this medium will lead to new effective properties for this particle. This was systematically studied for an electron in an ionic or polar lattice: the electron charge distorts the lattice, and the electron together with the lattice deformation is a new, heavier composite object called a polaron. This "polaronic effect" turns out to be ubiquitous in physical systems. Its most recent realization is the dressing of impurity atoms in a quantum gas of atoms cooled down to the nanokelvin regime where the gas turns into a superfluid, i.e. a state of matter exhibiting frictionless flow. The quantum gas embodiment of the polaron problem is particularly useful to study polaron physics since quantum gases are tunable and controllable to a high degree of precision by experimentalists. Hence, polarons can be brought into regimes hitherto inaccessible, where many-body theory can be tested in unprecedented ways. In that respect, superfluid Fermi gases show even more promise than superfluid Bose gases, as they possess a much richer and more tunable spectrum of elementary excitations that can dress the impurity atom. In this project, we will provide an in-depth study of the polaronic effects in these superfluid Fermi gases.This will lead not only to a better understanding of polaron physics, but also to new insights on the formation of superfluid Cooper pairs of fermionic atoms.
Date:1 Jan 2020 →  31 Dec 2023
Disciplines:Degenerate quantum gases and atom optics