A Rydberg impurity in a Fermi sea.

Rudolf Grimm

Jesper Levinsen, Meera M. Parish

Jhih-Shih You, Richard Schmidt, Dmitri A. Ivanov +2 more

John Sous, H. R. Sadeghpour, T. C. Killian +2 more

The authors demonstrate that a Rydberg impurity in a Fermi sea leads to a formation of a shell structure of occupied orbitals analogous to the nuclear shell model. At low gas densities, the paper uncovers a rotational blockade that inhibits molecule formation. This suppressed chemical reactivity also leaves its trace in the high-density regime.

Izak Snyman

I study the dynamical correlations that a quantum impurity induces in the Fermi sea to which it is coupled. I consider a quantum transport setup in which the impurity can be realized in a double quantum dot. The same Hamiltonian describes tunneling states in metallic glasses, and can be mapped onto the Ohmic spin-boson model. It exhibits a Fermi edge singularity, i.e., many fermion correlations result in an impurity decay rate with a nontrivial power-law energy dependence. I show that there is a simple relation between temporal impurity correlations on the one hand and the linear response of the Fermi sea to external perturbations on the other. This results in a power-law singularity in the space and time dependence of the nonlocal polarizability of the Fermi sea, which can be detected in transport experiments.

F F Bellotti, T. Frederico, M T Yamashita +3 more

We consider two identical impurities immersed in a Fermi sea for a broad range of masses and for both interacting and non-interacting impurities. The interaction between the particles is described through attractive zero-range potentials and the problem is solved in momentum space. The two impurities can attach to a fermion from the sea and form three-body bound states. The energy of these states increase as function of the Fermi momentum k F , leading to three-body bound states below the Fermi energy. The fate of the states depends highly on two- and three-body thresholds and we find evidence of medium-induced Borromean-like states in 2D. The corrections due to particle-hole fluctuations in the Fermi sea are considered in the three-body calculations and we show that in spite of the fact that they strongly affect both the two- and three-body systems, the correction to the point at which the three-body states cease to exist is small.