Self-trapping of Fermi and Bose gases under spatially modulated repulsive nonlinearity and transverse confinement

Dilute Fermi and Bose Gases

We give a unified perspective on the properties of a variety of quantum liquids using the theory of quantum phase transitions. A central role is played by a zero density quantum critical point which is argued to control the properties of the dilute gas. An exact renormalization group analysis of such quantum critical points leads to a computation of the universal properties of the dilute Bose g...

Experiments with Degenerate Bose and Fermi Gases

Two sets of studies are described in this thesis. In the first set, an atom interferometry technique was developed for the measurement of the fine structure constant using a BoseEinstein Condensate. In the second set, degenerate Fermi gases were prepared and their properties explored in a regime of strong interactions. We have developed an atom interferometer which is capable of measuring with ...

Cooling and Trapping a Bose-Fermi Mixture of Dilute Atomic Gases

Self-trapping of impurities in Bose-Einstein condensates: Strong attractive and repulsive coupling

We study the interaction-induced localization – the so-called self-trapping – of a neutral impurity atom immersed in a homogeneous Bose-Einstein condensate (BEC). Based on a Hartree description of the BEC we show that – unlike repulsive impurities – attractive impurities have a singular ground state in 3d and shrink to a point-like state in 2d as the coupling approaches a critical value β⋆. Mor...

Self-trapping of impurities in Bose-Einstein condensates: Arbitrarily strong attractive and repulsive coupling

We study the interaction-induced localization – the so-called self-trapping – of a neutral impurity atom immersed in a homogeneous Bose-Einstein condensate (BEC). Based on a Hartree description of the BEC we show that – unlike repulsive impurities – attractive impurities have a singular ground state in 3d and shrink to a point-like state in 2d as the coupling approaches a critical value β⋆. Mor...