56,417 research outputs found
Probing Neutral Majorana Fermion Edge Modes with Charge Transport
We propose two experiments to probe the Majorana fermion edge states that
occur at a junction between a superconductor and a magnet deposited on the
surface of a topological insulator. Combining two Majorana fermions into a
single Dirac fermion on a magnetic domain wall allows the neutral Majorana
fermions to be probed with charge transport. We will discuss a novel
interferometer for Majorana fermions, which probes their Z_2 phase. This setup
also allows the transmission of neutral Majorana fermions through a point
contact to be measured. We introduce a point contact formed by a
superconducting junction and show that its transmission can be controlled by
the phase difference across the junction. We discuss the feasibility of these
experiments using the recently discovered topological insulator Bi_2 Se_3.Comment: 4 page
Electricity from photovoltaic solar cells: Flat-Plate Solar Array Project final report. Volume VII: Module encapsulation
The Flat-Plate Solar Array (FSA) Project, funded by the U.S. Government and managed by the Jet Propulsion Laboratory, was formed in 1975 to develop the module/array technology needed to attain widespread terrestrial use of photovoltaics by 1985. To accomplish this, the FSA Project established and managed an Industry, University, and Federal Government Team to perform the needed research and development.
The objective of the Encapsulation Task was to develop, demonstrate, and qualify photovoltaic (PV) module encapsulation systems that would provide 20-year (later increased to 30-year) life expectancies in terrestrial environments, and which would be compatible with the cost and performance goals of the FSA Project. The scope of the Encapsulation Task included the identification, development, and evaluation of material systems and configurations required to support and protect the optically and electrically active solar cell circuit components in the PV module operating environment. Encapsulation material technologies summarized in this report include the development of low-cost ultraviolet protection techniques, stable low-cost pottants, soiling resistant coatings, electrical isolation criteria, processes for optimum interface bonding, and analytical and experimental tools for evaluating the long-term durability and structural adequacy of encapsulated modules. Field testing, accelerated stress testing, and design studies have demonstrated that encapsulation materials, processes, and configurations are available that will meet the FSA cost and performance goals. Thirty-year module life expectancies are anticipated based on accelerated stress testing results and on extrapolation of real-time field exposures in excess of 9 years
Lies on the Lips: Dying Declarations, Western Legal Bias, and Unreliability as Reported Speech
When one party is killed by another, there are often no witnesses to the murder other than the killer and the victim who is now absent. In some circumstances, the victim has enough life left to utter some final words to an individual who happens to be in the vicinity of the crime. Usually these statements, known in legal terms as dying declarations, relate to the circumstances of the victim\u27s death, including the identity of the perpetrator. If the crime is investigated by law enforcement authorities, the final words of the victim can be reported by the individual who received this last utterance. If the matter goes to trial, this report may be heard in a courtroom by judge and jury who will decide the fate of the accused, which may include loss of liberty or even death
Multiwavelength Observations of GX 339-4 in 1996. II. Rapid X-ray Variability
As part of our multiwavelength campaign of GX 339-4 observations in 1996 we
present the rapid X-ray variability observed July 26 using the RXTE when the
source was in a hard state (= soft X-ray low state). We found that the source
was extremely variable, with many bright flares. The flares have relatively
symmetric time profiles. There are a few time intervals where the flux rises
steadily and then drops suddenly, sometimes to a level lower than the average
before the increase. Hardness ratios showed that the source was slightly softer
when the flux was brighter. The power density spectra (PDS) were also
complicated and we found that broken power laws do not provide adequate fits to
any of them. Instead a pair of zero-centered Lorentzians gives a good general
description of the shape of the PDS. We found several quasi-periodic
oscillations (QPO), including some that are harmonically spaced with the most
stable frequency at 0.35 Hz. While the overall rms variability of the source
was close to being constant throughout the observation (29% integrating between
0.01 and 50 Hz), there is a small but significant change in the PDS shape with
time. More importantly, we show that the soft 2-5 keV band is more variable
than the harder 5-10 and 10-40 keV bands, which is unusual for this source and
for other black hole candidates. Cross correlation functions (CCF) between
these bands show that the light curve for the 10-40 keV band lags that of the
2-5 keV band by 5 msec.Comment: Submitted to Astrophysical Journal. 20 pages. 8 figure
Differential expansion for link polynomials
The differential expansion is one of the key structures reflecting group
theory properties of colored knot polynomials, which also becomes an important
tool for evaluation of non-trivial Racah matrices. This makes highly desirable
its extension from knots to links, which, however, requires knowledge of the
-symbols, at least, for the simplest triples of non-coincident
representations. Based on the recent achievements in this direction, we
conjecture a shape of the differential expansion for symmetrically-colored
links and provide a set of examples. Within this study, we use a special
framing that is an unusual extension of the topological framing from knots to
links. In the particular cases of Whitehead and Borromean rings links, the
differential expansions are different from the previously discovered.Comment: 11 page
Spin-dependent transport in a quasiballistic quantum wire
We describe the transport properties of a 5 m long one-dimensional (1D)
quantum wire. Reduction of conductance plateaux due to the introduction of
weakly disorder scattering are observed. In an in-plane magnetic field, we
observe spin-splitting of the reduced conductance steps. Our experimental
results provide evidence that deviation from conductance quantisation is very
small for electrons with spin parallel and is about 1/3 for electrons with spin
anti-parallel. Moreover, in a high in-plane magnetic field, a spin-polarised 1D
channel shows a plateau-like structure close to which
strengthens with {\em increasing} temperatures. It is suggested that these
results arise from the combination of disorder and the electron-electron
interactions in the 1D electron gas.Comment: 4 pages, 5 figures, latex to be published in Phys. Rev. B (15/3/2000
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