699 research outputs found
Non-Abelian Anyon Collider
A collider, where particles are injected to a beam splitter from opposite
sides, has been used for identifying quantum statistics of identical particles.
The collision leads to bunching of the particles for bosons and antibunching
for fermions. In recent experiments, a collider was applied to a fractional
quantum Hall regime hosting Abelian anyons. The observed negative cross
correlation of electrical currents cannot be understood with fermionic
antibunching. Here we predict, based on a conformal field theory and
non-perturbative treatment of non-equilibrium anyon injection, that the
collider provides a tool for direct observation of the braiding statistics of
various Abelian and non-Abelian anyons. Its dominant process is not direct
collision between injected anyons, contrary to common expectation, but braiding
between injected anyons and an anyon excited at the collider. The dependence of
the resulting negative cross correlation on the injection currents
distinguishes non-Abelian SU(2) anyons, Ising anyons, and Abelian Laughlin
anyons.Comment: Main text: 7 pages, 3 figures, Supplementary text: 8 pages, 3 figure
Gambling and sexual behaviors in African-American adolescents
Objectives: Late adolescence represents a developmental risk period when many youth become involved in multiple forms of high-risk behaviors with adverse consequences. This study assessed the degree to which two such behaviors, adolescent sexual behaviors and gambling, were associated in a community-based sample with a large African-American presence. Study design: Data are derived from a cohort study. This study focuses on 427 African-American participants with complete information on gambling and sexual behaviors by age 18 (72% of original cohort). Gambling involvement and related problems were based on responses to the South Oaks Gambling Screen — Revised for Adolescents. Several questions assessed sexual behaviors, including age of initiation. Multivariable logistic regression models adjusted for demographics, intervention status, impulsivity, depressive and anxiety symptoms, and alcohol and illegal drug use. Results: Almost half of the sample (49%, n = 211) had gambled at least once before age 18. More gamblers than non-gamblers had initiated sexual intercourse by age 18 (aOR: 2.29 [1.16, 4.52]). Among those who had initiated sexual activity, more gamblers than non-gamblers with high impulsivity levels at age 13 (vs. low impulsivity levels) had become pregnant or had impregnated someone. Among those who had initiated sexual activity by age 18, more male gamblers had impregnated someone by age 18 as compared to female gamblers becoming pregnant. Conclusions: Gambling and sexual behaviors often co-occur among adolescents. Such findings prompt the need for the inclusion of gambling, an often overlooked risky behavior, in behavioral prevention/intervention programs targeting adolescents
Partitioning of Diluted Anyons Reveals their Braiding Statistics
Correlations of partitioned particles carry essential information about their
quantumness. Partitioning full beams of charged particles leads to current
fluctuations, with their autocorrelation (AC, shot noise) revealing the
particle's charge. This is not the case when the partitioned particle beams are
diluted. Bosons or fermions will exhibit particles antibunching (due to their
discreteness). However, when partitioning anyons, such as the quasiparticles in
fractional quantum Hall states (FQH), the AC unveils an essential aspect of
their exchange statistics: their 'braiding phase'. Here, we describe detailed
measurements of partitioning diluted anyonic edge modes of the FQH 1/3-state.
The measured excess AC agrees with our theory of braiding in the 'time-domain'
- with a braiding angle of 2{\theta}=2{\pi}/3 - without any fitting parameters.
Our work offers a relatively straightforward and simple method to observe the
braiding statistics of other exotic states, such as non-abelian states, without
resorting to complex interference experiments.Comment: 8 pages, 5 figure
Long-Term Reliability of Polyimide Electrode Array in Rabbit Retina
Korea Health 21 R&D Project MOHW A050251, NBS-ERC supported by
KOSE
Reliable Multivalued Conductance States in TaOx, Memristors through Oxygen Plasma-Assisted Electrode Deposition with in Situ-Biased Conductance State Transmission Electron Microscopy Analysis
Transition metal oxide-based memristors have widely been proposed for applications toward artificial synapses. In general, memristors have two or more electrically switchable stable resistance states that device researchers see as an analogue to the ion channels found in biological synapses. The mechanism behind resistive switching in metal oxides has been divided into electrochemical metallization models and valence change models. The stability of the resistance states in the memristor vary widely depending on: oxide material, electrode material, deposition conditions, film thickness, and programming conditions. So far, it has been extremely challenging to obtain reliable memristors with more than two stable multivalued states along with endurances greater than similar to 1000 cycles for each of those states. Using an oxygen plasma-assisted sputter deposition method of noble metal electrodes, we found that the metal-oxide interface could be deposited with substantially lower interface roughness observable at the nanometer scale. This markedly improved device reliability and function, allowing for a demonstration of memristors with four completely distinct levels from similar to 6 x 10(-6) to similar to 4 x 10(-8) S that were tested up to 10(4) cycles per level. Furthermore through a unique in situ transmission electron microscopy study, we were able to verify a redox reaction-type model to be dominant in our samples, leading to the higher degree of electrical state controllability. For solid-state synapse applications, the improvements to electrical properties will lead to simple device structures, with an overall power and area reduction of at least 1000 times when compared to SRAM.11Ysciescopu
Assessment of the APCC Coupled MME Suite in Predicting the Distinctive Climate Impacts of Two Flavors of ENSO during Boreal Winter
Forecast skill of the APEC Climate Center (APCC) Multi-Model Ensemble (MME) seasonal forecast system in predicting two main types of El Nino-Southern Oscillation (ENSO), namely canonical (or cold tongue) and Modoki ENSO, and their regional climate impacts is assessed for boreal winter. The APCC MME is constructed by simple composite of ensemble forecasts from five independent coupled ocean-atmosphere climate models. Based on a hindcast set targeting boreal winter prediction for the period 19822004, we show that the MME can predict and discern the important differences in the patterns of tropical Pacific sea surface temperature anomaly between the canonical and Modoki ENSO one and four month ahead. Importantly, the four month lead MME beats the persistent forecast. The MME reasonably predicts the distinct impacts of the canonical ENSO, including the strong winter monsoon rainfall over East Asia, the below normal rainfall and above normal temperature over Australia, the anomalously wet conditions across the south and cold conditions over the whole area of USA, and the anomalously dry conditions over South America. However, there are some limitations in capturing its regional impacts, especially, over Australasia and tropical South America at a lead time of one and four months. Nonetheless, forecast skills for rainfall and temperature over East Asia and North America during ENSO Modoki are comparable to or slightly higher than those during canonical ENSO events
Reflections on the Cost of Low-Cost Whole Genome Sequencing: Framing the Health Policy Debate
The cost of whole genome sequencing is dropping rapidly. There has been a great deal of enthusiasm about the potential for this technological advance to transform clinical care. Given the interest and significant investment in genomics, this seems an ideal time to consider what the evidence tells us about potential benefits and harms, particularly in the context of health care policy. The scale and pace of adoption of this powerful new technology should be driven by clinical need, clinical evidence, and a commitment to put patients at the centre of health care policy
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