6,306 research outputs found
High-Resolution Imaging and Optical Control of Bose-Einstein Condensates in an Atom Chip Magnetic Trap
A high-resolution projection and imaging system for ultracold atoms is
implemented using a compound silicon and glass atom chip. The atom chip is
metalized to enable magnetic trapping while glass regions enable high numerical
aperture optical access to atoms residing in the magnetic trap about 100
microns below the chip surface. The atom chip serves as a wall of the vacuum
system, which enables the use of commercial microscope components for
projection and imaging. Holographically generated light patterns are used to
optically slice a cigar-shaped magnetic trap into separate regions; this has
been used to simultaneously generate up to four Bose-condensates. Using
fluorescence techniques we have demonstrated in-trap imaging resolution down to
2.5 micronsComment: 4 pages, 5 figures, 12 reference
Photovoltaic Oscillations Due to Edge-Magnetoplasmon Modes in a Very-High Mobility 2D Electron Gas
Using very-high mobility GaAs/AlGaAs 2D electron Hall bar samples, we have
experimentally studied the photoresistance/photovoltaic oscillations induced by
microwave irradiation in the regime where both 1/B and B-periodic oscillations
can be observed. In the frequency range between 27 and 130 GHz we found that
these two types of oscillations are decoupled from each other, consistent with
the respective models that 1/B oscillations occur in bulk while the
B-oscillations occur along the edges of the Hall bars. In contrast to the
original report of this phenomenon (Ref. 1) the periodicity of the
B-oscillations in our samples are found to be independent of L, the length of
the Hall bar section between voltage measuring leads.Comment: 4 pages, 4 figure
Possible observation of phase coexistence of the fractional quantum Hall liquid and a solid
We have measured the magnetoresistance of a very low density and an extremely
high quality two-dimensional hole system. With increasing magnetic field
applied perpendicularly to the sample we observe the sequence of insulating,
fractional quantum Hall liquid, and insulating phases. In both of the
insulating phases in the vicinity of the filling the
magnetoresistance has an unexpected oscillatory behavior with the magnetic
field. These oscillations are not of the Shubnikov-de Haas type and cannot be
explained by spin effects. They are most likely the consequence of the
formation of a new electronic phase which is intermediate between the
correlated Hall liquid and a disorder pinned solid.Comment: 5 pages, 4 figure
Microwave photoresistance of a high-mobility two-dimensional electron gas in a triangular antidot lattice
The microwave (MW) photoresistance has been measured on a high-mobility
two-dimensional electron gas patterned with a shallow triangular antidot
lattice, where both the MW-induced resistance oscillations (MIRO) and
magnetoplasmon (MP) resonance are observed superposing on sharp commensurate
geometrical resonance (GR). Analysis shows that the MIRO, MP, and GR are
decoupled from each other in these experiments.Comment: 5 pages, 4 figures, paper accepted by PR
- âŚ