Tue, January 1, 2013

Spin-Orbit Suppression of Cold Inelastic Collisions of Aluminum and Helium

Cold collisions between atoms play a critical role in much of atomic physics, being responsible for few-body interactions, thermalization, trap loss and decoherence.  The development of a detailed understanding of collisions is therefore crucial to the continued expansion of the field into new atomic systems, an expansion that has already led to the discovery of...

Sun, January 1, 2012

Vacuum-Induced Transparency

Sun, January 1, 2012

Initialization and readout of spin chains for quantum information transport

In these works we studied theoretically and experimentally the many-body dynamics of spin systems and analyzed conditions that would allow for their use in quantum communication.

Sun, January 1, 2012

Compressibility of an ultracold Fermi gas with repulsive interactions

To study the effect of repulsive interactions on the equation of state of a Fermi we have measured the isothermal compressibility of the gas as a function of interaction strength [1].  The strength of repulsive interactions for 6Li atoms can be arbitrarily tuned by varying the magnetic field around a broad Feshbach resonance centered at...

Sun, January 1, 2012

Formation of Ultracold Fermionic NaLi Feshbach Molecules

We have produced NaLi Feshbach molecules from an ultracold mixture of bosonic 23Na and fermionic 6Li [1]. Precise magnetic field sweeps across a narrow Feshbach resonance convert 5% of free atoms into weakly bound molecules, corresponding to a molecule number of 5 × 104.   NaLi is only the second fermionic heteronuclear molecule produced at ultracold...

Sun, January 1, 2012

Ultracold Fermionic Feshbach Molecules of 23Na40K

We report on the formation of ultracold fermionic Feshbach molecules of $^{23}$Na$^{40}$K, the first fermionic molecule that is chemically stable in its ground state. The lifetime of the nearly degenerate molecular gas exceeds 100 ms in the vicinity of the Feshbach resonance. The measured dependence of the molecular binding energy on the magnetic field demonstrates...

Sun, January 1, 2012

Heavy Solitons in a Fermionic Superfluid

Topological excitations are found throughout nature, in proteins and DNA, as dislocations in crystals, as vortices and solitons in superfluids and superconductors, and generally in the wake of symmetry-breaking phase transitions. In fermionic systems, topological defects may provide bound states for fermions that often play a crucial role for the system’s transport properties. Famous examples...

Sun, January 1, 2012

Spin-Injection Spectroscopy of a Spin-Orbit Coupled Fermi Gas

The coupling of the spin of electrons to their motional state lies at the heart of recently discovered topological phases of matter. Here we create and detect spin-orbit coupling in an atomic Fermi gas, a highly controllable form of quantum degenerate matter. We reveal the spin-orbit gap via spin-injection spectroscopy, which characterizes the energy-momentum dispersion...

Sun, January 1, 2012

Quantum nonlinear optics with single photons enabled by strongly interacting atoms

We have realized a quantum nonlinear medium that transmits one, but absorbs two photons. This is accomplished by coupling slowly traveling photons in an atomic gas to highly excited, strongly interacting Rydberg states. This result opens not only possibilities for single-photon sources, but may also enable deterministic quantum gates between photons.

Sat, January 1, 2011

Quantum degenerate Bose-Fermi mixture of chemically different atomic species with widely tunable interactions

We have created a quantum degenerate Bose-Fermi mixture of 23Na and 40K with widely tunable interactions via broad interspecies Feshbach resonances. Twenty Feshbach resonances between 23Na and 40K were identified. The large and negative triplet background scattering length between 23Na and 40K causes a sharp enhancement of the fermion density in the presence of a...