5 research outputs found
Nonuniversal transmission phase lapses through a quantum dot: An exact-diagonalization of the many-body transport problem
Systematic trends of nonuniversal behavior of electron transmission phases
through a quantum dot, with no phase lapse for the transition N=1 -> N=2 and a
lapse of pi for the N=2 -> N=3 transition, are predicted, in agreement with
experiments, from many-body transport calculations involving exact
diagonalization of the dot Hamiltonian. The results favor shape anisotropy of
the dot and strong e-e repulsion with consequent electron localization, showing
dependence on spin configurations and the participation of excited doorway
transmission channels.Comment: Published version. REVTEX4. 4 pages with 3 color figures. For related
papers, see http://www.prism.gatech.edu/~ph274cy
Bosonic molecules in rotating traps
We present a variational many-body wave function for repelling bosons in
rotating traps, focusing on rotational frequencies that do not lead to
restriction to the lowest Landau level. This wave function incorporates
correlations beyond the Gross-Pitaevskii (GP) mean field approximation, and it
describes rotating boson molecules (RBMs) made of localized bosons that form
polygonal-ring-like crystalline patterns in their intrinsic frame of reference.
The RBMs exhibit characteristic periodic dependencies of the ground-state
angular momenta on the number of bosons in the polygonal rings. For small
numbers of neutral bosons, the RBM ground-state energies are found to be always
lower than those of the corresponding GP solutions, in particular in the regime
of GP vortex formation.Comment: To appear in Phys. Rev. Lett. LATEX, 5 pages with 5 figures. For
related papers, see http://www.prism.gatech.edu/~ph274cy
Single Impurity In Ultracold Fermi Superfluids
The role of impurities as experimental probes in the detection of quantum
material properties is well appreciated. Here we study the effect of a single
classical magnetic impurity in trapped ultracold Fermi superfluids. Depending
on its shape and strength, a magnetic impurity can induce single or multiple
mid-gap bound states in a superfluid Fermi gas. The multiple mid-gap states
could coincide with the development of a Fulde-Ferrell-Larkin-Ovchinnikov
(FFLO) phase within the superfluid. As an analog of the Scanning Tunneling
Microscope, we propose a modified RF spectroscopic method to measure the local
density of states which can be employed to detect these states and other
quantum phases of cold atoms. A key result of our self consistent Bogoliubov-de
Gennes calculations is that a magnetic impurity can controllably induce an FFLO
state at currently accessible experimental parameters.Comment: 5 pages, 3 figures; added calculations for 3
Classical magnetic impurity in ultracold fermi superfluids
In cold atom experiments, we have tools to create spin dependent optical potential, which gives us the possibility to achieve classical magnetic impurity in cold atom systems. Here we study the physics of magnetic impurity. A localized magnetic impurity can induce a mid-gap bound state, the Yu-Shiba state, in superfluid Fermi gas. We propose a modified RF spectroscopy to measure the local density of states, as a cold-atom analog of STM, which may be used to detect Yu-Shiba state. In addition, magnetic impurity can locally induce population imbalance in the system, potentially providing a method to realize FFLO-like state in a controlled way. We demonstrate such a possibility by solving the self-consist Bogoliubov-de Gennes equations