W. I. McAlexander

Elastic and inelastic collisions of 6Li atoms in magnetic and optical traps

We use a full coupled channels method to calculate collisional properties of magnetically or optically trapped ultracold 6-Li. The magnetic field dependence of the s-wave scattering lengths of several mixtures of hyperfine states are determined, as are the decay rates due to exchange collisions. In one case, we find Feshbach resonances at B = 0.08 T and B = 1.98 T. We show that the exact coupled channels calculation is well approximated over the entire range of magnetic fields by a simple analytical calculation.

Superfluid state of atomic 6 Li in a magnetic trap

We report on a study of the superfluid atate of spin-polarized atomic 6-Li confined in a magnetic trap. Density profiles of this degenerate Fermi gas, and the spatial distribution of the BCS order parameter are calculated in the local density approximation. The critical temperature is determined as a function of the number of particles in the trap. Furthermore we consider the mechanical stability of an interacting two-component Fermi gas, both in the case of attractive and repulsive interatomic interactions. For spin-polarized 6-Li we also calculate the decay rate of the gas, and show that within the mechanically stable regime of phase space, the lifetime is long enough to preform experiments on the gas below and above the critical temperature if a bias magnetic field of about 5 T is applied. Moreover, we propose that a measurement of the decay rate of the system might signal the presence of the superfluid state.

Photoassociative spectroscopy of long‐range states of ultracold 6Li2 and 7Li2

We have obtained spectra of the high‐lying vibrational levels of the A1Σu+ and 13Σg+states of both 6Li2 and 7Li2 via photoassociation of colliding ultracold atoms confined to a magneto‐optical trap. Because of the low collision energies (∼1 mK), very high spectroscopic resolution is realized, and sensitivity is greatest for the usually difficult to access long‐range states. Binding energies relative to the center of gravity of the resolved hyperfine structure are given for the A1Σu+ vibrational levels v =62–88 for 6Li2 and v=65–97 for 7Li2, and the 13Σg+ vibrational levels v=56–84 for 6Li2 and v=62–90 for 7Li2. These are extremely long‐range levels with outer classical turning points ranging from 25 a0 to 220 a0, where a0 is the Bohr radius. The spectra arise mainly from s‐wave collisions, and therefore exhibit little rotational structure.

Superfluid state of atomic 6Li in a magnetic trap

We report on a study of the superfluid atate of spin-polarized atomic 6-Li confined in a magnetic trap. Density profiles of this degenerate Fermi gas, and the spatial distribution of the BCS order parameter are calculated in the local density approximation. The critical temperature is determined as a function of the number of particles in the trap. Furthermore we consider the mechanical stability of an interacting two-component Fermi gas, both in the case of attractive and repulsive interatomic interactions. For spin-polarized 6-Li we also calculate the decay rate of the gas, and show that within the mechanically stable regime of phase space, the lifetime is long enough to preform experiments on the gas below and above the critical temperature if a bias magnetic field of about 5 T is applied. Moreover, we propose that a measurement of the decay rate of the system might signal the presence of the superfluid state.

Superfluid state of atomic6Liin a magnetic trap

We report on a study of the superfluid atate of spin-polarized atomic 6-Li confined in a magnetic trap. Density profiles of this degenerate Fermi gas, and the spatial distribution of the BCS order parameter are calculated in the local density approximation. The critical temperature is determined as a function of the number of particles in the trap. Furthermore we consider the mechanical stability of an interacting two-component Fermi gas, both in the case of attractive and repulsive interatomic interactions. For spin-polarized 6-Li we also calculate the decay rate of the gas, and show that within the mechanically stable regime of phase space, the lifetime is long enough to preform experiments on the gas below and above the critical temperature if a bias magnetic field of about 5 T is applied. Moreover, we propose that a measurement of the decay rate of the system might signal the presence of the superfluid state.

Superfluid state of atomic Li-6 in a magnetic trap

We report on a study of the superfluid atate of spin-polarized atomic 6-Li confined in a magnetic trap. Density profiles of this degenerate Fermi gas, and the spatial distribution of the BCS order parameter are calculated in the local density approximation. The critical temperature is determined as a function of the number of particles in the trap. Furthermore we consider the mechanical stability of an interacting two-component Fermi gas, both in the case of attractive and repulsive interatomic interactions. For spin-polarized 6-Li we also calculate the decay rate of the gas, and show that within the mechanically stable regime of phase space, the lifetime is long enough to preform experiments on the gas below and above the critical temperature if a bias magnetic field of about 5 T is applied. Moreover, we propose that a measurement of the decay rate of the system might signal the presence of the superfluid state.

The Superfluid State of Atomic Li6 in a Magnetic Trap

We report on a study of the superfluid atate of spin-polarized atomic 6-Li confined in a magnetic trap. Density profiles of this degenerate Fermi gas, and the spatial distribution of the BCS order parameter are calculated in the local density approximation. The critical temperature is determined as a function of the number of particles in the trap. Furthermore we consider the mechanical stability of an interacting two-component Fermi gas, both in the case of attractive and repulsive interatomic interactions. For spin-polarized 6-Li we also calculate the decay rate of the gas, and show that within the mechanically stable regime of phase space, the lifetime is long enough to preform experiments on the gas below and above the critical temperature if a bias magnetic field of about 5 T is applied. Moreover, we propose that a measurement of the decay rate of the system might signal the presence of the superfluid state.