Researchers develop metamaterials able to control spread of light

center_img Journal information: Science More information: Spin-Optical Metamaterial Route to Spin-Controlled Photonics, Science 10 May 2013: Vol. 340 no. 6133 pp. 724-726 DOI: 10.1126/science.1234892ABSTRACTSpin optics provides a route to control light, whereby the photon helicity (spin angular momentum) degeneracy is removed due to a geometric gradient onto a metasurface. The alliance of spin optics and metamaterials offers the dispersion engineering of a structured matter in a polarization helicity–dependent manner. We show that polarization-controlled optical modes of metamaterials arise where the spatial inversion symmetry is violated. The emerged spin-split dispersion of spontaneous emission originates from the spin-orbit interaction of light, generating a selection rule based on symmetry restrictions in a spin-optical metamaterial. The inversion asymmetric metasurface is obtained via anisotropic optical antenna patterns. This type of metamaterial provides a route for spin-controlled nanophotonic applications based on the design of the metasurface symmetry properties. Current electronic components used in communications technology are considered by most in the field to be bulky compared to other types of equipment. Also, engineers find it difficult to integrate such devices with typical microelectronic circuitry. For that reason, scientists have been looking for ways to change the way such devices are designed and built. In this new effort, the team from Israel has created a class of metamaterials that control the way light spreads, paving the way for entirely new types of communications devices.The new metamaterials developed by the team are based on spin optics where photon helicity degeneracy is prevented due to the geometric gradient that exists on their surface. They are also anisotropic—they don’t behave the same way when measured from different directions. Also, unlike current technology, they are polarization-dependent. Together these features cause light waves to propagate in ways not typically seen in current communications equipment. In addition, because of their polarization dependence, design engineers can create new devices that allow for a novel way to control communication devices—by the selection of the polarization of light at the outset. The researchers also report the new materials don’t show inversion symmetry on their surface. Citation: Researchers develop metamaterials able to control spread of light (2013, May 10) retrieved 18 August 2019 from https://phys.org/news/2013-05-metamaterials.html Thermal radiation modes emitted by spin-optical metamaterial based on inversion asymmetric kagome lattice. The illuminated color spirals symbolize the photon helicity-split due to optical Rashba effect. False-colored electric field distribution near the metasurface obtained by numerical simulation. The design of photonic metasurface symmetries via geometric gradient of the optical antenna patterns provides a route to control light-matter interaction at the nanoscale. Credit: Technion-Israel Institute of Technologylast_img read more

Physicists use magnetism simulation software to model US presidential elections

first_imgConnected by commuters. This map shows connections between home and work counties for the most common connections (top 10%), according to census data. Researchers used these data as part of a simulation of voting behavior in US presidential elections. Credit: J. Fernández-Gracia et al., Phys. Rev. Lett. (2014) PausePlay% buffered00:0000:00UnmuteMuteDisable captionsEnable captionsSettingsCaptionsDisabledQuality0SpeedNormalCaptionsGo back to previous menuQualityGo back to previous menuSpeedGo back to previous menu0.5×0.75×Normal1.25×1.5×1.75×2×Exit fullscreenEnter fullscreen (Phys.org) —A team of physicists working at IFISC in Palma de Mallorca, Spain has used a computer simulation originally designed to model the transition of iron between magnetized states to create a model to do something similar for voting patterns in the United States. In their paper published in Physical Review Letters, the team describes how they used factors of influence by interactions between voters to create a model that accurately predicted how influenced voters would vote. Creating a computer model that can accurately predict the outcome (the winner and loser) of an election is still just a pipe dream, of course. What is possible though is modeling human behavior as it relates to voter patterns. One such behavior is the tendency of voters to be impacted by the opinions of others, whether those of people that live near them, or those that commute to places where they work. It’s this tendency that the team in Spain has tried to model.To model voter tendencies on a computer the researchers narrowed down the factors of influence that lead to voting tendencies to just two: the proportion of Republicans versus Democrats in a given voter’s home county and the proportion of Republicans versus Democrats where they work. This (and probability and statistics) allowed for modeling the impact of influence in a variety of situations. One example would be where a voter is Democrat but lives or works among Republicans, a situation that can in many cases cause them to vote Republican. The model allowed for increasing or decreasing the distance between such voters to allow for an increase or dissipation of influence impacting possible voting trends. Play 36 years of simulated US presidential election maps have some statistical properties that remain constant in time and are similar to the real election results. (Counties that voted for the Democrat are blue; those for the Republican are red. The intensity of the color indicates the margin of victory.) Credit: J. Fernández-Gracia/IFISC/ Physics Focus Instead of trying to predict who would win a given election, the model alternatively shows trends by focusing on margin of victory—by noting voter trends across varying regions—with visual representations of changes in voting behavior as distance between impact factors change. To find out if their model was accurate, the team input census data from the nine presidential elections covering the years 1980 to 2012. Doing so revealed previously unknown correlations between regions that actually existed in the real world of vote casting and graphically illustrated the influence that voters have on one another. One striking example was the county to county variability displayed, indicating the percentage of votes going to either party—showing that the national mean changes from election to election, but not the degree of fluctuation between counties. Explore further Swing voters hold more sway over candidates on economic issuescenter_img This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. Citation: Physicists use magnetism simulation software to model US presidential elections (2014, April 24) retrieved 18 August 2019 from https://phys.org/news/2014-04-physicists-magnetism-simulation-software-presidential.html © 2014 Phys.org Journal information: Physical Review Letters More information: Is the Voter Model a Model for Voters? Phys. Rev. Lett. 112, 158701 – Published 18 April 2014. journals.aps.org/prl/abstract/ … ysRevLett.112.158701ABSTRACTThe voter model has been studied extensively as a paradigmatic opinion dynamics model. However, its ability to model real opinion dynamics has not been addressed. We introduce a noisy voter model (accounting for social influence) with recurrent mobility of agents (as a proxy for social context), where the spatial and population diversity are taken as inputs to the model. We show that the dynamics can be described as a noisy diffusive process that contains the proper anisotropic coupling topology given by population and mobility heterogeneity. The model captures statistical features of U.S. presidential elections as the stationary vote-share fluctuations across counties and the long-range spatial correlations that decay logarithmically with the distance. Furthermore, it recovers the behavior of these properties when the geographical space is coarse grained at different scales—from the county level through congressional districts, and up to states. Finally, we analyze the role of the mobility range and the randomness in decision making, which are consistent with the empirical observations.last_img read more

A slice of Bengal in Dilli Haat

With Durga Puja around the corner, Bengal is the flavour at Dilli Haat. What better reason for shopaholics to pick up handicrafts and exquisite saris from the state which is known for saris? A total of 32 self-help groups from various districts of West Bengal have taken over Dilli Haat. They are a part of a West Bengal government organised initiative which is being organised at Dilli Haat.  ‘This has been organised so that Bengalis in Delhi can do their puja shopping. It is also an opportunity for artisans from West Bengal to showcase their wares,’ said a West Bengal government official. Apart from 10 stalls each for handlooms and handicrafts, there are two stalls for jute products and a food court that is selling delicious snacks like cutlet, luchi alur dom, mishti doi among others.  Members of the Savitri self help group has travelled all the way from North 24 Parganas with jute shoes, bags and jewellery. ‘We have already finished most of our stock and more will be coming soon. Business has been good over the weekend,’ says a happy member. Others have travelled with kantha stitch saris, kurtas, dupattas and stoles. These are in fabrics like cotton, tussar, silk and georgette and have beautiful kantha work done on them. The renowned Dhaniakhali taant saris are there too. One stall we liked had leather products from Santiniketan. There were pretty coin purses, moneysaver pouches, sling bags, folders and others. Go take a look.DETAILAt: Dilli Haat, INAOn Till: 30 September read more

and step two

first_imgYou remember them for Laila and the Channel V Launchpad and then well frankly you would not have heard too much about them except a few concerts here and there. But then these guys are all set to change that! The band is about to launch their next studio album Phir Se. Armed with their signature hooklines and brand of ‘confused pop’, these guys are raring to go with a six-city tour that includes Mumbai, Kolkata, Hyderabad, Bangalore, Pune and of course – Delhi.  Also Read – ‘Playing Jojo was emotionally exhausting’Phir se is an Electronic album produced through Rock N Roll sounds with as the band members say, ‘nostalgic ideas of the future’. With this album, Faridkot for the first time features five guest artists namely, Aditi Singh Sharma (Vocal Duet on Gulz), Suhail Yusuf Khan (Saarangi solo on Aaina), Gyan Singh (Tabla on Jats), Subadhra Kamath and Sonam Gaychen Wangdi (Background vocals).  The album was mixed in LA, California and mastered at the coveted Mastering Palace in New York, USA. Also Read – Leslie doing new comedy special with NetflixThe album features ten tracks that sway between the many emotions: From introspection in Aaina, realisation of the energy source that makes us who we are in- Bijli, to love for the natural and cosmic beauty around us captured in Gul and Suno, Phir Se encapsulates many shades of wonder.The basic idea behind the second  album is to evoke a variable take on trance – in musicality. Faridkot seeks to create a sort of repeating and evolving musical trance with their songs, similar to electronic music.  Except that the album is made of organic elements such as vocal harmonies, guitars and drums. ‘All of these elements and ideas were combined to make songs with inherent pop structures which we love. We love pop-music because it doesn’t reflect a type of music or a particular sound. It reflects the timeline of the society we live in. Everything is verse/chorus/bridge like all pop-music, except we wanted to make it a little interesting this time around’, says IP Singh, vocalist Faridkot.Do not miss this one. And this article works best because we are reminding you today! Head over.last_img read more

Ode to the mountains

first_imgThe Beckoning of Gyanganj a fiction written by Chandan K Pathak has been released in the capital. The event took place at the India habitat Centre in the presence of many eminent personalities. Film actor Adil Hussain graced the occasion as the chief guest. Anamika Yaduvanshi- Life Coach and Motivational speaker and president of Astitva Foundation, John Uche Jesus- Nigeria born Indian Fashion designer and CEO of Diamond Ark, Avininder Singh- hospitality professional and Asst. Prof. Manjeet  Baruah- North East Studies from JNU were among others who attended the programme.  Also Read – ‘Playing Jojo was emotionally exhausting’Gyanganj is a mystical abode of immortal beings located in the remote Himalayas. It influences series of events from two eras and results in The Beckoning of Gyanganj, a cocktail of Himalayan adventures, spiritualism, love and romance, hatred and politics, sufferings and revolt. Having travelled to the Himalayas number of times in search of elusive true-saints and at times even contemplating to retire to a cave there to meditate for the rest of his life to attain spiritual knowledge, there was a phase of Chandan K Pathak’s life when he juggled with the materialistic and spiritual influences with lots of challenges. Through this book, he has tried to weave his own story encompassing all aspects of love, romance, spiritualism and politics. The Beckoning of Gyanganj is his second book. His first effort Footprints was a collection of short stories which were earlier in form of blogs. Pathak is currently working on his third novel (untitled) which is loosely based on a real life story from 1980s.last_img read more

Notification out on 25 DA hike

first_imgKolkata: The notification declaring a total additional dearness allowance (DA) of 25 percent has been issued on Thursday. There will also be an ad-hoc increase in the existing daily rate of wages by Rs 53 from January 1 in 2019.The memorandum stated that “state government employees drawing basic pay up to Rs 80,000 per month, shall draw with effect from January 1, 2019 DA at 125 percent by taking into account the existing DA at 100 percent…” It has also been stated that “there will be a further ad-hoc increase in the existing daily rate of wages by Rs 53, with effect from January 1, 2019, for the daily wage workers under the government, whose wages are not regulated by any statutory provision like the Minimum wages Act.” Also Read – Heavy rain hits traffic, flightsIn connection with the DA, it has been stated that it will be applicable for teachers and non-teaching employees of government-aided educational institutions, employees of statutory bodies, government undertakings, Panchayats including Panchayat Karmee and Municipal Corporations, Municipalities and local bodies. It may be recalled that on June 19, Chief Minister Mamata Banerjee had announced the release of additional DA for the state government employees, with the merger of 10 percent interim relief and it was 90 percent more than that of the Left Front government. She had said: “We are now announcing additional DA, despite there being financial constraints. But the decision to release the DA has been taken as I had given my word to the employees.”last_img read more

Fun and frolic

first_imgThe little kids moved about, some working on their drawings, some concentrating on winning the games and some wailing out loud and rolling on the floor to get their demands fulfilled in an event which saw the amalgamation of education and entertainment. Meenakshi Lekhi, Member of Parliament, inaugurated the two-day event Jack n Jill, the fun expo for children, which was held in the national Capital on Saturday and Sunday. Along with games, there were activities and competitions which kept the little ones busy. Also Read – ‘Playing Jojo was emotionally exhausting’With the new generation spending their time with latest gadgets and hoping for instant gratification in terms of entertainment these days, it has become necessary to introduce the children to the activities which fuse education within entertainment. Giving a modern twist to traditional fun and frolic, the event was a success, as large number of children walked-in and indulged in various activities like games, fashion show, dance, fancy dress competition, magic show and rakhi-making competition. Also Read – Leslie doing new comedy special with NetflixA nine-year-old child Gurmay Singh Malwai said, “I enjoyed the competition where the participant had to match elements to their state and those who got all elements correctly matched were winners. I am sad that I couldn’t get all elements matched but it was fun.”Jyoti Mayal, organiser and CEO of Redhat Communications said, “It has been a fun filled first edition of the expo with children between the age of 0-10 years enjoying a number of activities to the hilt. We are delighted to see such a great response from both children and their parents. It was also fascinating to see so many young and inquisitive minds and connect with them under one roof. The entire venue has been brimming with positive energy and we are certain that the next edition will be a bigger success, where we will be able to inculcate tourism, wellness and education from the formative years in school.” Parents too were busy buying toys and clothes while their children participated in the activities. A grandparent was observing her elder grandchild participate in an activity. When asked about her experience of the event, the 62-year-old Poonam said, “Bacche khush toh hum khush (if the kids are happy we are happy).”last_img read more

Bollywood has to be more adventurous Ketan Mehta

first_imgDirector Ketan Mehta feels Bollywood should attempt making adventurous films. “There are all kind of filmmakers and all kind of reasons of a making a film. The Hindi film industry has to be more adventurous and make all kind of films. I start working on a script first and then think who should be cast,” Mehta told a media person. Mehta is looking forward to the release of Manjhi – The Mountain Man, an upcoming biographical film based on the life of Dashrath Manjhi. A poor labourer from a village in Bihar, he spent 22 years carving a path through a mountain. Mehta is happy with the response he is getting for the film, which will hit the screens on August 21. “The moment the trailer was released it was heartening to see an amazing response. It was surprising to see an overwhelming response from the youth. They identified with the spirit of the man,” the filmmaker said.last_img read more