4,842 research outputs found
A long-lived spin-orbit-coupled degenerate dipolar Fermi gas
We describe the creation of a long-lived spin-orbit-coupled gas of quantum
degenerate atoms using the most magnetic fermionic element, dysprosium.
Spin-orbit-coupling arises from a synthetic gauge field created by the
adiabatic following of degenerate dressed states comprised of optically coupled
components of an atomic spin. Because of dysprosium's large electronic orbital
angular momentum and large magnetic moment, the lifetime of the gas is limited
not by spontaneous emission from the light-matter coupling, as for gases of
alkali-metal atoms, but by dipolar relaxation of the spin. This relaxation is
suppressed at large magnetic fields due to Fermi statistics. We observe
lifetimes up to 400 ms, which exceeds that of spin-orbit-coupled fermionic
alkali atoms by a factor of 10-100, and is close to the value obtained from a
theoretical model. Elastic dipolar interactions are also observed to influence
the Rabi evolution of the spin, revealing an interacting fermionic system. The
long lifetime of this weakly interacting spin-orbit-coupled degenerate Fermi
gas will facilitate the study of quantum many-body phenomena manifest at longer
timescales, with exciting implications for the exploration of exotic
topological quantum liquids.Comment: 11 pages, 8 figures, one appendi
Trapping ultracold dysprosium: a highly magnetic gas for dipolar physics
Ultracold dysprosium gases, with a magnetic moment ten times that of alkali
atoms and equal only to terbium as the most magnetic atom, are expected to
exhibit a multitude of fascinating collisional dynamics and quantum dipolar
phases, including quantum liquid crystal physics. We report the first laser
cooling and trapping of half a billion Dy atoms using a repumper-free
magneto-optical trap (MOT) and continuously loaded magnetic confinement, and we
characterize the trap recycling dynamics for bosonic and fermionic isotopes.
The first inelastic collision measurements in the few partial wave, 100 uK to 1
mK, regime are made in a system possessing a submerged open electronic f-shell.
In addition, we observe unusual stripes of intra-MOT <10 uK sub-Doppler cooled
atoms.Comment: 4+ pages, 4 figures; minor edits in V
Integration of fiber coupled high-Q silicon nitride microdisks with atom chips
Micron scale silicon nitride (SiN_x) microdisk optical resonators are
demonstrated with Q = 3.6 x 10^6 and an effective mode volume of 15 (\lambda /
n)^3 at near visible wavelengths. A hydrofluoric acid wet etch provides
sensitive tuning of the microdisk resonances, and robust mounting of a fiber
taper provides efficient fiber optic coupling to the microdisks while allowing
unfettered optical access for laser cooling and trapping of atoms. Measurements
indicate that cesium adsorption on the SiN_x surfaces significantly red-detunes
the microdisk resonances. A technique for parallel integration of multiple (10)
microdisks with a single fiber taper is also demonstrated.Comment: Published vesion. Minor change
Observation of low-field Fano-Feshbach resonances in ultracold gases of dysprosium
We report the observation of resonance-like loss in the trap population of
ultracold dysprosium as a function of magnetic field, which we attribute to
anisotropy-induced Fano-Feshbach resonances arising from Dy's large magnetic
dipole moment and nonzero electronic orbital angular momentum. We recorded
these resonances for four different isotopes, three bosonic and one fermionic,
over a field range of 0-6 G and show that the number of resonances changes
significantly as a function of temperature, even in the nK regime. Most of the
observed resonances are of very narrow width. The fermionic isotope, unlike its
bosonic counterparts, possesses nonzero nuclear spin and exhibits a much higher
density of resonances.Comment: 5 pages, 3 figure
An atom mirror etched from a hard drive
We describe the fabrication of an atom mirror by etching of a common hard
drive, and we report the observation of specular retroreflection of 11 uk
cesium atoms using this mirror. The atoms were trapped and cooled above the
hard drive using the mirror magneto-optical trap technique, and upon release,
two full bounces were detected. The hard drive atom mirror will be a useful
tool for both atom optics and quantum computation.Comment: 4 pages, 4 figure
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