8 research outputs found
Experimental realization of Laughlin quasiparticle interferometers
Laughlin quasiparticles are the elementary excitations of a highly-correlated
fractional quantum Hall electron fluid. They have fractional charge and obey
fractional statistics. The quasiparticles can propagate quantum-coherently in
chiral edge channels, and constructively or destructively interfere. Unlike
electrons, the interference condition for Laughlin quasiparticles has a
non-vanishing statistical contribution that can be observed experimentally. Two
kinds of interferometer devices have been realized. In the primary-filling
interferometer, the entire device has filling 1/3, and the e/3 edge channel
quasiparticles encircle identical e/3 island quasiparticles. Here the flux
period is h/e, same as for electrons, but the back-gate charge period is e/3.
In the second kind of interferometer, a lower density edge channel at filling
1/3 forms around a higher density island at filling 2/5, so that e/3 edge
quasiparticles encircle e/5 island quasiparticles. Here we observe
superperiodic oscillations with 5h/e flux and 2e charge periods, both
corresponding to excitation of ten island quasiparticles. These periods can be
understood as imposed by the anyonic braiding statistics of Laughlin
quasiparticles.Comment: in Proc. of EP2DS-17 (Genoa, Italy, 2007
Full Counting Statistics of Multiple Andreev Reflections in incoherent diffusive superconducting junctions
We present a theory for the full distribution of current fluctuations in
incoherent diffusive superconducting junctions, subjected to a voltage bias.
This theory of full counting statistics of incoherent multiple Andreev
reflections is valid for arbitrary applied voltage. We present a detailed
discussion of the properties of the first four cumulants as well as the low and
high voltage regimes of the full counting statistics. The work is an extension
of the results of Pilgram and the author, Phys. Rev. Lett. 94, 086806 (2005).Comment: Included in special issue Spin Physics of Superconducting
heterostructures of Applied Physics A: Materials Science & Processin
NEOTROPICAL XENARTHRANS: a data set of occurrence of xenarthran species in the Neotropics
Xenarthrans – anteaters, sloths, and armadillos – have essential functions for ecosystem maintenance, such as insect control and nutrient cycling, playing key roles as ecosystem engineers. Because of habitat loss and fragmentation, hunting pressure, and conflicts with 24 domestic dogs, these species have been threatened locally, regionally, or even across their full distribution ranges. The Neotropics harbor 21 species of armadillos, ten anteaters, and six sloths. Our dataset includes the families Chlamyphoridae (13), Dasypodidae (7), Myrmecophagidae (3), Bradypodidae (4), and Megalonychidae (2). We have no occurrence data on Dasypus pilosus (Dasypodidae). Regarding Cyclopedidae, until recently, only one species was recognized, but new genetic studies have revealed that the group is represented by seven species. In this data-paper, we compiled a total of 42,528 records of 31 species, represented by occurrence and quantitative data, totaling 24,847 unique georeferenced records. The geographic range is from the south of the USA, Mexico, and Caribbean countries at the northern portion of the Neotropics, to its austral distribution in Argentina, Paraguay, Chile, and Uruguay. Regarding anteaters, Myrmecophaga tridactyla has the most records (n=5,941), and Cyclopes sp. has the fewest (n=240). The armadillo species with the most data is Dasypus novemcinctus (n=11,588), and the least recorded for Calyptophractus retusus (n=33). With regards to sloth species, Bradypus variegatus has the most records (n=962), and Bradypus pygmaeus has the fewest (n=12). Our main objective with Neotropical Xenarthrans is to make occurrence and quantitative data available to facilitate more ecological research, particularly if we integrate the xenarthran data with other datasets of Neotropical Series which will become available very soon (i.e. Neotropical Carnivores, Neotropical Invasive Mammals, and Neotropical Hunters and Dogs). Therefore, studies on trophic cascades, hunting pressure, habitat loss, fragmentation effects, species invasion, and climate change effects will be possible with the Neotropical Xenarthrans dataset