Indium arsenide may provide clues to quantum information processing

first_img“We’re not saying we’ve built a quantum computer,” Andreas Fuhrer tells, “but this is an important first step towards spin manipulation via the spin-orbit interaction.” Citation: Indium arsenide may provide clues to quantum information processing (2007, July 23) retrieved 18 August 2019 from Fuhrer, a scientist with the Department of Solid State Physics/Nanometer Consortium at Lund University in Sweden, points out that one way quantum information processing might come about is through the manipulation of spin states. Fuhrer and his colleagues have directly measured spin-orbit interaction strength in a two-electron molecule along a nanowire made of indium arsenide (InAs). With the first example of tunable few-electron quantum dots in a material with strong spin-orbit interaction, they believe that spin-orbit based spin manipulation is a step closer to becoming reality.Fuhrer worked with Fasth and Samuelson, also associated with the Solid State Physics/Nanometer Consortium, and with Golovach and Loss from the University of Basel in Switzerland to understand the spin-orbit interaction of electrons in quantum dots along a nanowire. Their findings are published in a piece in Physical Review Letters titled, “Direct Measurement of the Spin-Orbit Interaction in a Two-Electron InAs Nanowire Quantum Dot.”“This is the first time tunable quantum dots with a single electron have been realized in indium arsenide nanowires,” Fuhrer explains via email. “While other material systems often require complex gate arrangements to confine the electrons in artificial atoms, the nanowire basically has the confinement in two directions built in due to its nanoscale crosssection.”The scheme set up by Fuhrer and his colleagues works fairly simply. Indium arsenide nanowires self-assemble during crystal growth into rods. “It’s not a bulk semiconductor like some other materials used for this purpose,” Fuhrer points out over the phone. “It is a really thin wire that is an ideal starting point for making quantum dots. You can induce as many of these artificial atoms along the nanowire as you like and couple them to each other.” In addition, the spin-orbit interaction might allow the spin states of quantum dots to be manipulated merely by applying pulses to the gates that confine the electrons. “Usually six gates, or sometimes more, need to be used.” In the paper, Fuhrer and his coauthors use four gates, but they have data to show that it would work with two gates per quantum dot. Additionally, most efforts to manipulate spin make use of conventional electron spin resonance, a technique that can be difficult to bring close to each individual quantum dot. “We expect that with our scheme it will be enough to pulse the gate.” Fuhrer then goes on to expound in greater detail through email: “When the gate is pulsed, you jerk the electron to one side along the nanowire, and by the movement of the orbital part of the electron wavefunction, also rotate the spin because of the spin-orbit coupling. This promises to be faster and easier than existing spin-manipulation techniques if we can demonstrate that spin states live long enough for computations to be feasible.”The main problem with this setup, Fuhrer admits, is that quantum information can be lost through decoherence. Typically, the idea is to decouple the spin from everything, including orbital motion, in order to avoid destroying the quantum calculations. “We’re hoping, though, that by strongly confining the electrons and by keeping track of the orbital energy levels, we can get around this.” Fuhrer says that realizing few-electron quantum dots in InAs is an important first step. “The next step is to measure the spin lifetimes and manipulate the spins.” He points out that within the next five to ten years efforts will be made to use such a setup for quantum information processing. “We still need to study this alternate option of spin state control. It could offer the possibility of manipulating qubits more easily.”Copyright 2007 All rights reserved. This material may not be published, broadcast, rewritten or redistributed in whole or part without the express written permission of 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.last_img read more

Imaginary Phone iPhone as a hand phone w video

first_img( — Once you have had your smart phone for a while using your touch screen becomes a bit of second nature. You begin to know where you icons are and how to do things without looking down at the screen. What if that means that in order to do some of those operations from memory, you did not have to take your phone out at all? Researchers in Germany are working on a new tool that would allow you to use your phone while it is still inside your pocket, by recreating the actions on the palm of your hand. The system, called ‘Imaginary Phone’, which would pair the movements that you made on your palm with the screen of your phone relies on a depth-sensitive camera that is designed to pick up the sliding and tapping motion that are made on your palm. The system uses a special software that is designed to analyze the video and send a wireless radio signal to the iPhone in question. More information: Project page: … imaginary_phone.html Citation: I-maginary Phone: iPhone as a hand phone? (w/ video) (2011, May 24) retrieved 18 August 2019 from The tool, which the team, led by Patrick Baudisch, professor of computer science at the Hasso Plattner Institute in Potsdam, Germany, pictures this as a short term solution that is used when touching your phone would not be desirable, say when you are washing your dog or paining your living room. The lack of visual feedback on the phone does not seem to be an issues for the users. A study submitted to the User Interface Software and Technology conference in October showed that about two-thirds of iPhone users could find the location of their apps with up to 80 percent accuracy. © 2010 Palm’s new smart phone synchronizes with iTunes Explore further 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.last_img read more

Study finds color and thickness of eggshells in wild birds related to

first_img Citation: Study finds color and thickness of eggshells in wild birds related to light level exposure (2014, July 30) retrieved 18 August 2019 from Explore further Different bird species lay their eggs in different places—most everyone knows that—some birds lay their eggs in nests in trees, others on the ground, while still others lay them in nests hidden from view inside of holes, etc. Wild bird eggs also come in a wide variety of colors and some have markings that serve as camouflage. Less well known is that shell thickness varies between species and previous research has found that some pigments in shells help fight embryo infections. In this new study, the researchers set out to determine if shell color and thickness might be related to how much sunlight exposure the eggs get. To find out, they analyzed eggshells residing in various museums—measuring thickness, pigment concentration, permeability, and their surface reflectance spectrum (color)—in all eggshells from 74 different species were examined. Most specifically, they focused on measuring how much light could come through a particular shell using a spectrophotometer. Once the examinations were complete, the researchers related what they’d learned about the eggshells to the environment in which the eggs were incubated and that led to correlations between color and sunlight exposure.The team found that eggs exposed to a lot of sunlight, such as those nested on the ground, had more pigment than did those that were hidden away, such as those tucked in tree holes or concealed in burrows. Eggs from hidden nests were the ones that were pure white, allowing the most light to penetrate the shell. The team also found that species with longer incubation periods tended to also have more color and thicker shells.The researchers conclude that eggshell thickness and color are a form of sunscreen, allowing in just the right amount of UV radiation—if there is too little light the babies inside won’t develop properly—if there’s too much, damage would result. Dinosaur egg study supports evolutionary link between birds and dinosaurs A team of biology researchers with members from Australia, the U.S., Czech Republic and the U.K. has found a correlation between eggshell color and thickness and the amount of light that shines on the eggs during incubation. In their paper published in Functional Ecology, the team describes their study that involved the analysis of eggshells from many native bird species in Britain and the results they found in doing so. More information: Functional Ecology, 29 JUL 2014. DOI: 10.1111/1365-2435.12314center_img Journal information: Functional Ecology © 2014 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. Image: Flickrlast_img read more

What An Insect Can Teach Us About Adapting To Stress

first_imgThe epic destruction wrought by swarms of locusts is downright biblical. Exodus tells of a plague that left nothing green in all of Egypt, and we’ve seen these harbingers of destruction at work in modern day Australia, Argentina and Israel, just to name a few. But for centuries, one essential piece of information about these strange insects eluded scientists: Where do they come from? These massive swarms just seemed to pop up out of nowhere, decimate everything and then vanish. What if we told you that you could learn a lot about handling adversity from the life of a bug? In their explorations of humans and how we interact with the world around us, the team that makes NPR’s Invisibilia stumbled on a surprising fact about the insect world — one that could inspire a new way of looking at ourselves. center_img Read the whole story: NPRlast_img read more

UN panel calls for North Korea referral to international court

first_imgThe UN General Assembly committee dealing with human rights on Tuesday called for the UN Security Council to consider referring North Korea to the International Criminal Court (ICC) for alleged crimes against humanity. The vote followed a UN Commission of Inquiry report published in February detailing wide-ranging abuses in North Korea, including prison camps, systematic torture, starvation and killings comparable to Nazi-era atrocities. The resolution passed by the UN Third Committee linked the alleged abuses to the policies of North Korea’s leadership and called on the Security Council to consider targeted sanctions against those responsible. Also Read – Pro-Govt supporters rally as Hong Kong’s divisions deepenThe vote increases political pressure on North Korea but it is largely symbolic. It is unlikely to lead to action in the International Criminal Court at The Hague, which looks at serious abuses like genocide and other crimes against humanity.Diplomats said N Korea ally China would probably use its Security Council veto power to stop any ICC referral. They said Beijing’s stance would likely be supported by Russia. China and Russia backed an amendment to the resolution by Cuba, which was voted down, to remove the call to refer North Korea to the ICC.last_img read more

An ode to classical beats

first_imgIndia Habitat Centre is hosting a musical evening titled An Ode to Indian Classical Music featuring Bishnumurari Chattopadhyay (popularly known as Champak). The  show that will witness Khayal, Thumri, Tarana and Bhajan will also Siddhartha Bhattacharyya will be accompanying Chattopadhyay on tabla. The classical singer believes that nothing rotates and run without the existence of God. With his larger-than-life heart, he owes his success story to many people in life. “I was initiated in music by my elder sister Purabi Chatterjee, a well-known classical vocalist and exponent of Nazrulgeeti. And then, my trainings with vocal maestro, Prof. Subhas Chakladar, a disciple of legendary Ustad Mehendi Hussain Khan of Rampur Gharana, and Ustad Abdul Gaffur Khan of Jaipur Gharana enhanced the skills,” shares the singer.  Also Read – ‘Playing Jojo was emotionally exhausting’Having completed his MA in Music from Kolkata, he took taalim of ‘tala’ and ‘laya’ from the Tabla maestro, Ustad Shaukat Ali Khan. A recipient of Sangeet Gunakar from ‘Sadarang Sangeet Samaj’, West Bengal, Bishnumurari has the distinction of participating in a large number of music conferences in Kolkata and Delhi. With more than 25 years experience in teaching music, he has also directed group performances in Bengali light, semi-classical music, Nazrulgeeti, and composed songs of different genres, including devotional hymns for agomoni, bhajans, raga-based songs, adhunik songs and patriotic songs in Hindi for children, which have been universally appreciated. Champak has had the opportunity to regale great maestros like Pt. Ravi Shankar with his performances from time to time, and get their invaluable appreciation and blessings.When: May 25Where: Amaltas Hall, India Habitat CentreTiming: 6:30 onwardslast_img read more

90 injured at PM Modis rally in Midnapore after pandal collapses

first_imgKolkata: Indiscipline by few BJP workers led to the collapse of a portion of a pandal during Prime Minister Narendra Modi’s address at Midnapore College ground on Monday in which around 90 people were injured, five of them seriously.The pandal was situated close to the main podium from where the Prime Minister addressed the gathering.Chief Minister Mamata Banerjee got in touch with the West Midnapore district administration and inquired about the condition of the injured. She instructed Midnapore Medical College and Hospital authorities to take care of the injured properly. Also Read – Rain batters Kolkata, cripples normal lifeShe tweeted later: “We pray for the speedy recovery of all those injured at the Midnapore rally today. The government is giving all help for medical treatment. “In a joint statement issued by TMC’s secretary general Partha Chatterjee and party’s MP Derek O’Brien held the state BJP responsible for the accident and said they should take responsibility.The accident took place when some BJP workers climbed to the top of the tent to have a clearer view of Narendra Modi. The latter, before addressing his speech, requested them to come down. But the workers turned a deaf ear and the pandal collapsed at around 12.50 pm when Modi was delivering his speech. Also Read – Speeding Jaguar crashes into Mercedes car in Kolkata, 2 pedestrians killedThe injured were rushed to Midnapore Medical College and Hospital. The Prime Minister also paid a visit to those admitted there, inquired about their health and also spoke to a few.Because of heavy rain that had hit the district, the ground was wet and the bamboos used to set up the makeshift pandal could not bear the additional load of the people particularly when they climbed to the top. The bamboos broke leading to the collapse of the pandal.The state BJP leaders had supervised the setting up of the makeshift tent. They even failed to bring down those supporters who had climbed to the top of the pandal. Senior police officers said as the ground was wet, the state leaders should not have allowed anyone to climb up. But there was no initiative from their side which finally led to the collapse.Hospital authorities said most of the injured had been released after treatment. Five have been admitted and doctors are monitoring their condition.The district administration has ordered a probe regarding the matter.last_img read more

Poetry festival A treat for audiences in City Santiniketan

first_imgIt’s spring,a time to celebrate poetry. It would be more of a meet among poets, their friends, listeners, followers meant for exchanging their creative thoughts through poetry. It is an initiative of Abrittilok, Kolkata, in association with Bratati Parampara in collaboration with Bengali Department, Visva Bharati, Sahitya Akademy and Ministry of Culture, Govt of India between Feb 22 and Feb 25, 2018, in Santiniketan and Kolkata.A curtain raiser will take place in association with the Press Club Kolkata on Feb 20 in the august presence of Bratya Basu( IT Minister, WB) followed by the audio enactment of Mrityunjay, a presentation by Nandikar at Kolkata Press Club. This year, the focus is on the poets from North Eastern region of India. On Feb 22, at Lipika (Santiniketan), the inaugural ceremony would be graced by Amal Pal (Head, Bengali Dep, Visva Bharati ), Gautam Paul ( Office-In-Charge, Sahitya Akademy,Kolkata), Malabika Mitra( President, Abrittilok,Kolkata), Bratati Bandyopadhyay (Director, Bratati Parampara ) at 5.30 PM. It would be followed by an evening of poetry with the inaugural recitation by Bratati Parampara, Santiniketan, solo recitation by Bratati Bandyopadhyay,Shubhabrata Roy Chowdhury, Avik Ghosh, Amartya Mukhopadhyay, Ei Banglar Shikore( Compilation by Soumitra Mitra ), presentation by Abrittilok and Bratati Parampara , Jagannath Bose and Urmimala Bose (Joint recitation). On Feb 23, the celebration of poetry would take place at Uttarayan Prangan. Inaugural recitation will be by the Techno India, Santiniketan. Poetry collage- Mrityur Poreo Jeno Hente Jete Pari by Soumitra Mitra, Sumantra Sengupta, Rabin Mazumdar, Nupur Bose and so on will e followed by the solo recitation by Debshankar Haldar, Sutapa Bandyopadhyay will be followed by Kobitar Gaan by Lopamudra Mitra, a musical presentation by Visva Bharati. Also Read – Add new books to your shelfThen it’s time for Kolkata. On Feb 24 and 25, the sessions will take place at P C Chandra Garden. On the first day, Shaoli Mitra will recite poems of Tagore followed by an audio enactment of Raktakarobi directed by Bratati Bandyopadhyay. The performers are Sumantra Sengupta, Srikanta Acharya, Kalyan Sen Barat, Madhubani Chatterjee, Manoj Murali Nayar, Alok Ray Ghatak, Bratati Bandyopadhyay, students of Kabyayan and so on. On the final day, Bratati Parampara will present Pratham Puja followed by a solo recitation by Soumitra Chatterjee, Pranati Tagore, Sohini Sengupta, Sovan Sundar Basu and then Tagore songs by Jayati Chakraborty. Special guests on the occasion will be Shankha Ghosh, Shirshendu Mukherjee and so on.last_img read more

Frequent dining out can harm your health

first_imgNext time you order a sandwich from your favourite fast food joint or plan a dinner with your friends at a nearby restaurant, you must give a try to home-cooked meal first. According to researchers, dining out more at restaurants, cafeterias and fast-food outlets may boost total levels of potentially health-harming chemicals called “phthalates” in the body, especially among pregnant women, children and teenagers.”Phthalates”, a group of chemicals used in food packaging and processing materials, are known to disrupt hormones in humans and are linked to a long list of health problems. Also Read – Add new books to your shelf”This study suggests food prepared at home is less likely to contain high levels of ‘phthalates’, chemicals linked to fertility problems, pregnancy complications and other health issues,” said senior author Ami Zota, Assistant Professor of Environmental and Occupational Health at Milken Institute School of Public Health, George Washington University.For the study, researchers used data from the US National Health and Nutrition Examination Survey (NHANES) collected between 2005 and 2014. Also Read – Over 2 hours screen time daily will make your kids impulsiveThe 10,253 participants in the study were asked to recall what they ate and where their food came from in the previous 24 hours.The researchers then analysed the links between what people ate and the levels of phthalate break-down products found in each participant’s urine sample.The team found that 61 per cent of the participants reported dining out the previous day. The study found that sandwiches consumed at fast food outlets, restaurants or cafeterias were associated with 30 per cent higher phthalate levels in all age groups. The researchers also found the association between phthalate exposure and dining out was significant for all age groups but the magnitude of association was highest for teenagers.last_img read more

Smaller expressions of a restless mind

first_imgFrom the realities of life that he has observed in the city he loves, to the men and animals that are depicted with passionate distortions, Shuvaprasanna has remained a restless innovator through an artistic journey spanning nearly half a century. Through all these creative years, he has contributed both to the artistic identity of Kolkata that remains his primary source of inspiration and to the creative consciousness of those who have fed on his bold initiatives. The large canvases in a string of impressive shows had seen him making sharp observations on social issues that had haunted him at different phases of his work. Also Read – Add new books to your shelfAt one point, the encounters with Gunter Grass became a turning point, shaping an artistic mind that was inevitably drawn towards broken images and a natural movement towards unconventional spaces. But seldom, if ever, has the artist chosen to shift his format from the large compositions where he could indulge in a good deal of creative freedom to the small format that he presented in his show called ‘Mixed Media’ at Art Exposure. The subjects were communicated in the visual language that was striking as ever but this time he sprang a pleasant surprise by transforming the idiom to a smaller format but largely with the same radical tendencies that, quite predictably, revealed the same kind of restless energy. Also Read – Over 2 hours screen time daily will make your kids impulsiveThe series of contemporary images in a smaller format came with a powerful blending of technical skill and social concern. The battered impressions of common men and women were as lasting in their impact as the refreshing warmth of flowery patterns that greet the visitor with a tender package of compositions and colours. Shuvaprasana never burdens the mind with complex statements even when he is seen to be driven by dark realities around him. His narratives mostly in an urban context are simple yet hard- hitting, easy to access and yet bold in their overall appeal. What makes the drawings of men and animals quite extraordinary is the power of their lines, the softness of his colours and the lingering effect of his distorted images. The sleeping elephant, birds locked in a romantic moment, mime artistes concealing the agony of life in comic postures, cats and crows frozen in their curious gestures and lovers lost in their fragile emotions all seem to be an integral part of his creative expression. The attention to detail and the perfection of his textures are unmistakable elements of his work. This time it acquired a fresh dimension in the intimate space of Art Exposure that Uma Mitra and Soma Bhowmik have visualised with care and artistic consciousness. This is evident from some of the shows that have been curated with an elegant flavour since the gallery opened its doors in 2006. Selections from two veterans – Lalu Prasad Shaw and Thota Vaikuntam – recaptured the faces in the social environment they were familiar with and, quite predictably, grabbed a resounding response. But in its concern for giving the art fraternity in Kolkata a glimpse of the emerging talent from other regions, the gallery brought experimental pen and ink drawings by Laxman Aelay that dealt with musicians eking out a livelihood in remote areas of rural Telengana. The same spirit of bringing veterans and prodigies on a common platform has brought Shuvaprasanna’s personal visual statements. Clearly there are influences drawn from his exposure to European masters that he acquired during his extensive travels but essentially they belong to his own environment and the city that has nourished his creative freedom. “As a conscious citizen or conscious worker, I can’t close my eyes. They are always open. So my way of looking and thinking continued to change through internal and external lessons and varied experiences at different point of time in my life. My language has been shifting, my concerns are changing, my approaches to art are seeking new forms and expressions”, the artist tells visitors who have expressed their curiosity about the new texture and format. But those who have been observing him had no reason to be surprised by the mixed media comprising acrylic, charcoal and ink that has served to take the new idiom to another level of popular interest. The show that added another dimension to the veteran’s impressive repertoire produced another splurge of structured metaphors that appealed to the eye as much as they stir the mind.last_img read more