Control of coherent backscattering by breaking optical reciprocity

Reciprocity is a universal principle that has a profound impact on many areas of physics. A fundamental phenomenon in condensed-matter physics, optical physics and acoustics, arising from reciprocity, is the constructive interference of quantum or classical waves which propagate along time-reversed paths in disordered media, leading to, for example, weak localization and metal-insulator transition. Previous studies have shown that such coherent effects are suppressed when reciprocity is broken. Here we show that by breaking reciprocity in a controlled manner, we can tune, rather than simply suppress, these phenomena. In particular, we manipulate coherent backscattering of light, also known as weak localization. By utilizing a non-reciprocal magneto-optical effect, we control the interference between time-reversed paths inside a multimode fiber with strong mode mixing, and realize a continuous transition from the well-known peak to a dip in the backscattered intensity. Our results may open new possibilities for coherent control of classical and quantum waves in complex systemsComment: Comments are welcom

Mobile edge computing for big-data-enabled electric vehicle charging

As one of the key drivers of smart grid, EVs are environment-friendly to alleviate CO2 pollution. Big data analytics could enable the move from Internet of EVs, to optimized EV charging in smart transportation. In this article, we propose a MECbased system, in line with a big data-driven planning strategy, for CS charging. The GC as cloud server further facilitates analytics of big data, from CSs (service providers) and on-the-move EVs (mobile clients), to predict the charging availability of CSs. Mobility-aware MEC servers interact with opportunistically encountered EVs to disseminate CSs' predicted charging availability, collect EVs' driving big data, and implement decentralized computing on data mining and aggregation. The case study shows the benefits of the MEC-based system in terms of communication efficiency (with repeated monitoring of a traffic jam) concerning the long-term popularity of EVs

The Performance of CRTNT Fluorescence Light Detector for Sub-EeV Cosmic Ray Observation

Cosmic Ray Tau Neutrino Telescopes (CRTNT) using for sub-EeV cosmic ray measurement is discussed. Performances of a stereoscope configuration with a tower of those telescopes plus two side-triggers are studied. This is done by using a detailed detector simulation driven by Corsika. Detector aperture as a function of shower energy above 10^17 eV is calculated. Event rate of about 20k per year for the second knee measurement is estimated. Event rate for cross calibration with detectors working on higher energy range is also estimated. Different configurations of the detectors are tried for optimization.Comment: 5 pages, 4 figures, submitted to HEP & N

Preparation of CNx/Carbon Nanotube Intramolecular Junctions by Switching Gas Sources in Continuous Chemical Vapour Deposition

Nitrogen-doped carbon nanotubes (CNx)/carbon nanotube intramolecular junctions were prepared by a simple continuous chemical vapour deposition (CVD) method at 650 °C. The catalyst was obtained by calcination of a layered double hydroxide precursor containing Fe and Mg. By switching between hexane and ethylenediamine repeatedly in the CVD process, multiple intramolecular junctions composed of CNx with a bamboo-like structure and empty hollow carbon nanotubes were observed, and such different structures at both sides of the junctions indicated some interesting properties and offered potential applications for future nanodevices.Keywords: Nitrogen-doped carbon nanotubes, junction, chemical vapour depositio