CarbonNanotube Memory that Really Competes

first_imgA side-view schematic of the single-walled carbon-nanotube field-effect transistor, showing the two halfnium dioxide layers (HfO2). The nanotube is represented by the honeycomb pattern in the center of the figure. VGS is the voltage across the transistor’s gate and source. (PhysOrg.com) — Researchers in Finland have created a form of carbon-nanotube based information storage that is comparable in speed to a type of memory commonly used in memory cards and USB “jump” drives. Researchers combine logic, memory to build a ‘high-rise’ chip 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: Carbon-Nanotube Memory that Really Competes (2009, January 26) retrieved 18 August 2019 from https://phys.org/news/2009-01-carbon-nanotube-memory.html The group’s memory scheme has a write-erase time of 100 nanoseconds, which is about 100,000 times faster than previously reported carbon-nanotube memory, and retains this ability over more than 10,000 write-erase cycles. The work is reported in the January 16, 2009, online edition of Nano Letters.”In terms of speed and endurance, our memory structure is as good as the commercially available Flash memory technologies,” said Helsinki University of Technology physicist Päivi Törmä, the paper’s corresponding author, to PhysOrg.com.The memory scheme stores information using single-walled carbon-nanotube transistors, specifically field-effect transistors, which are among the fastest carbon-nanotube electrical components. Each transistor consists of four key parts, the gate, source, drain, and substrate.As a substrate, Törmä and her colleagues chose a silicon wafer. In collaboration with Finnish technology-equipment company Beneq Oy, they applied a 20-nanometer-thick layer of hafnium oxide using atomic layer deposition, a technique used to deposit materials in very thin layers. The hafnium oxide separates the substrate, which was also used as the gate in this case, from the rest of the structure. Choosing hafnium dioxide as the gate “dielectric” material—an insulator placed between two conductors to separate them—appears to be the key to the device’s fast operation, as it can trap and release charge very quickly and efficiently.On top of the hafnium-oxide layer, the group deposited a few drops of a carbon-nanotube solution, produced using commercially available nanotubes with diameters between 1.2 and 1.5 nanometers and lengths of 100 to 360 nanometers. Using an atomic force microscope, they identified nanotubes with the proper alignment; only those nanotubes became transistors. They then created source and drain electrodes for each nanotube using the metal palladium, with the nanotube forming the transistor’s conductive channel. Finally, the researchers deposited another 20-nanometer layer of hafnium oxide on top of the nanotube transistor, to “passivate” the surface, preventing unwanted reactions.”The fast memory operation we have demonstrated could potentially also be realized using other carbon materials, such as carbon-nanotube bundles or graphene,” said Törmä.Each transistor stores information based on whether current is running through it. When the voltage applied across the transistor reaches a certain threshold, current flows, which can represent one bit of information, either a “0” or a “1” (bit is short for binary digit). For example, when the transistor is conducting it may represent a “1,” and when not conducting, a “0.”Each transistor can store information for about 150,000 seconds, or about 42 hours. This is quite short, although Törmä and her group think they can improve it by adding an oxide layer between the gate and the nanotube.Citation: Nano Lett., Article ASAP DOI: 10.1021/nl8029916Copyright 2008 PhysOrg.com. All rights reserved. This material may not be published, broadcast, rewritten or redistributed in whole or part without the express written permission of PhysOrg.com. Explore furtherlast_img read more


Researchers entangle a single electron spin to a single photon in a

first_img More information: 1. Quantum-dot spin–photon entanglement via frequency downconversion to telecom wavelength, Nature, 491, 421–425 (15 November 2012) doi:10.1038/nature11577AbstractLong-distance quantum teleportation and quantum repeater technologies require entanglement between a single matter quantum bit (qubit) and a telecommunications (telecom)-wavelength photonic qubit. Electron spins in III–V semiconductor quantum dots are among the matter qubits that allow for the fastest spin manipulation and photon emission, but entanglement between a single quantum-dot spin qubit and a flying (propagating) photonic qubit has yet to be demonstrated. Moreover, many quantum dots emit single photons at visible to near-infrared wavelengths, where silica fibre losses are so high that long-distance quantum communication protocols become difficult to implement. Here we demonstrate entanglement between an InAs quantum-dot electron spin qubit and a photonic qubit, by frequency downconversion of a spontaneously emitted photon from a singly charged quantum dot to a wavelength of 1,560 nanometres. The use of sub-10-picosecond pulses at a wavelength of 2.2 micrometres in the frequency downconversion process provides the necessary quantum erasure to eliminate which-path information in the photon energy. Together with previously demonstrated indistinguishable single-photon emission at high repetition rates, the present technique advances the III–V semiconductor quantum-dot spin system as a promising platform for long-distance quantum communication.2. Observation of entanglement between a quantum dot spin and a single photon, Nature, 491, 426–430 (15 November 2012) doi:10.1038/nature11573AbstractEntanglement has a central role in fundamental tests of quantum mechanics1 as well as in the burgeoning field of quantum information processing. Particularly in the context of quantum networks and communication, a main challenge is the efficient generation of entanglement between stationary (spin) and propagating (photon) quantum bits. Here we report the observation of quantum entanglement between a semiconductor quantum dot spin and the colour of a propagating optical photon. The demonstration of entanglement relies on the use of fast, single-photon detection, which allows us to project the photon into a superposition of red and blue frequency components. Our results extend the previous demonstrations of single-spin/single-photon entanglement in trapped ions, neutral atoms and nitrogen–vacancy centres to the domain of artificial atoms in semiconductor nanostructures that allow for on-chip integration of electronic and photonic elements. As a result of its fast optical transitions and favourable selection rules, the scheme we implement could in principle generate nearly deterministic entangled spin–photon pairs at a rate determined ultimately by the high spontaneous emission rate. Our observation constitutes a first step towards implementation of a quantum network with nodes consisting of semiconductor spin quantum bits. Level structure of quantum dot and spin manipulation. Credit: (c) Nature, 491, 421–425 (15 November 2012) doi:10.1038/nature11577 Explore further © 2012 Phys.org To create a quantum computer, scientists believe it will be necessary to combine or connect stationary quantum bits (qubits) with mobile or “flying” qubits. Thus, research has been focused on building a system in which this is possible. In this new research, quantum dots were used to represent the stationary particles while photons were used to represent those that fly. To connect them, the researchers relied on entanglement between pairs of particles and the properties they share.In their labs, both teams used very small semiconductors to trap a single electron, e.g. a quantum dot. They then both fired a laser at the dot to set its spin state to either up or down (representing “0” or “1”). Next both teams also fired another laser pulse at the dot to force it to a higher energy level. Doing so caused an entangled photon to be released as the energy decayed. The photon was emitted as either horizontally or vertically polarized with a wavelength that was demonstrated by either a red or blue color. It was at this stage that the work between the two teams diverged. To use the information from a (qubit) in a quantum system, only one of the two properties can be allowed to exist; thus the other must be removed. The first team’s work involved removing the color, the second, the polarization.To remove the color the first team ran the photon through a crystal that was also shot with a laser beam. Doing so caused the colors to smear which was enough to remove that property from the entangled particles. The second team removed the polarization by allowing the photon to pass through a polarizing filter which forced it into an anticlockwise state which effectively erased the shared property from the particles. Journal information: Naturecenter_img (Phys.org)—Two teams working independently have succeeded in entangling a single electron spin with a single photon in a solid-state platform. Both teams describe their process and results in papers they’ve had published in the journal Nature. The two teams used laser pulses fired at quantum dots to entangle pairs of electrons and photons then used different techniques to remove either the shared color that resulted or their polarization. Quantum computing: The light at the end of the tunnel may be a single photon Citation: Researchers entangle a single electron spin to a single photon in a quantum dot (2012, November 15) retrieved 18 August 2019 from https://phys.org/news/2012-11-entangle-electron-photon-quantum-dot.html 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


Flower power

first_imgThe theme of this year’s Festival was Vertical Gardens.As Delhi witnessed a pleasant days, visitors in huge numbers came to see the unique floras on display. More than 5000 various floras are on display at this year’s festival. The highlight of this year’s Festival is the specially designed Vertical Gardens of size 20 ft. X 30 ft.This year’s theme Vertical Gardens encourages the use of vertical space for gardens indoors and outdoors. It is enlightening, garden enthusiasts about planting on roofs, walls and creating structures within small spaces as green covers. Also Read – ‘Playing Jojo was emotionally exhausting’Various competitions were organized in more than 30 odd categories and an on the spot painting competition for children’s was also held today.Garden Tourism Festival is the only Festival in India where people finds plethora of floras on display. There are Rudraksh plants all the way from Nepal for sale, Orchids from Sikkim, Bonsai plants, Cacti etc. There were alos stalls where visitors could buy plants and other equipments.Apart from providing visitors a glimpse into some of the most exquisite flowers, Delhi Tourism has also created an Adventure Park at the venue to indulge visitors in outdoor activities such as Rappling, Flying Fox, Burma Bridge, Zorbing Ball etc. This zone is witnessing tremendous response from adventure enthusiasts.last_img read more


This is Her story

first_imgThe multi-faceted and impactful story of HeLa has been brought to India by QTP as part of its 15th anniversary celebrations.HeLa has been inspired by the book The Immortal Life of Henrietta Lacks by Rebecca Skloot, and is about ethics, equality and ownership of our DNA and will pose a question: ‘What is more human – the DNA that make up our bodies or the personalities that come from our souls?’ It is a true story of Henrietta Lacks, who in 1951 walked into the coloured section of the John Hopkins Hospital in Baltimore with a pain in her abdomen. A cell sample taken without her permission was used as the raw material for some of the most important scientific discoveries of the past 100 years. This solo, one-woman show by actor Adura Onashile, takes as its inspiration the true life story of Henrietta Lacks and the extraordinary life of the HeLa cell line. It is an all-consuming story, intertwining genetic identity, social responsibility and current ethical debates about human tissue research and ownership. Directed by Graham Eatough, performed by actor Adura Onashile, HeLa is produced by Iron-Oxide, Scotland’s leading large-scale companies that specialises in producing daring outdoor shows. HeLa is a fusion of video, music, monologue and physicality.The play was showcased at the Edinburgh Fringe Festival 2013 and ran to packed houses. HeLa was nominated for numerous Fringe Awards and also won the Flying Artichoke Award (Scottish Arts Club-Edinburgh Guide-Scottish Theatre Fringe Award). It also received nominations for Total Theatre Award 2013 and Amnesty International Freedom of Expression Award 2013.last_img read more


Kolkata Police organises campaign prohibiting use of mobile phones while walking on

first_imgKolkata: The Kolkata Police has organised an awareness campaign to make people realise the ill effects of using mobile phones while walking on roads.According to an officer of the Kolkata Traffic Police, it has been noticed that many accidents can be avoided if pedestrians in the city become a bit more careful and avoid using cell phones while walking on roads.A police officer said earlier people only used to speak over phone while walking. Though their concentration used to get diverted, at least they used to look straight while walking. But now the situation has turned worse as people keep texting while walking. Also Read – Heavy rain hits traffic, flightsMany were even found remaining glued to the screens of their cell phones while crossing a road. There were many instances when pedestrians were found walking on city roads using earphones to speak on cell phones or listen to songs. “This is more dangerous as many times they cannot realise that a vehicle is approaching when he or she is crossing a road and it often leads to an accident,” the police said.So, the police have started creating awareness among pedestrians so that they do not use cell phones while walking on roads. The awareness campaign was held mainly at two important locations in the city including Hare Street. Such initiatives have brought down the rate of accidents as Chief Minister Mamata Banerjee had launched the state-wide campaign Safe Drive Save Life.The Headquarter Traffic Guard took the initiative to create awareness on this particular issue and it was done by engaging school goers as it is considered that people easily accept when a child requests him or her to follow something.last_img read more


Rabindra Manch revamped

first_imgSiliguri: Rabindra Manch is soon going to host bright and colourful cultural programmes. “The renovation work of the stage had been encouraged by the Chief Minister and thus the responsibility has been handed over to the Siliguri Jalpaiguri Development Association,” said the Chairman of SJDA Sourav Chakraborty, during his visit to the newly inaugurated building at Shaktigarh in Siliguri.The North Bengal Development department has spent an amount of Rs 1,49,48,886 on the renovation of the building. The construction of the stage had commenced many days ago, but the NBDD had decided to take the responsibility of its completion due to some flaws that had erupted during the construction work.Rabindra Manch had been inaugurated by North Bengal Development minister Rabindranath Ghosh and Tourism minister Goutam Deb on October 4, 2017.last_img read more


Varsity at Mungpoo to be named Darjeeling Hill University

first_imgDarjeeling: The name of the State University to come up at Mungpoo, Darjeeling will be undergoing a change in nomenclature from “Greenfield University” to “Darjeeling Hill University.”Chief Minister Mamata Banerjee talking to media persons in Darjeeling on Tuesday stated: “It was a long standing demand of the people that a University come up in the Hills. The foundation stone of the new university ‘The Darjeeling Hill University’ will be laid on Wednesday. The university will come up at Mungpoo.” Also Read – Rain batters Kolkata, cripples normal lifeIncidentally, the Government programme at Darjeeling Chowrasta that was supposed to take place at 3pm on Wednesday has been rescheduled to 11am.Mamata Banerjee will lay the foundation stone of the University from this programme and head for Kolkata. “However, during the discussion on the bill we had requested that the nomenclature be changed as it is the sentiment of the Hill masses that a University come up which bears the identity of the region. The Chief Minister has honoured the sentiments of the people. Now, an amendment has to be brought in the winter session of the Assembly to change the nomenclature,” stated Amar Rai, MLA, Darjeeling.”We have already earmarked a land of 100-acre at Yogighaat in Mungpoo for the University. A new 8-km long road will be built through which the distance between Siliguri and the University will be a mere 45 minutes drive,” stated Binoy Tamang, Chairman, GTA.last_img read more


I know my style of singing is the future Indeep Bakshi

first_imgThe music sensation Indeep Bakshi, who has to its credit the popular number Saturday Saturday from Humpty Sharma ki Dulhania’ said that he is not intimidated by his contemporaries as he believes that every artist has his own style. Since when did you develop an interest in music?Academically, I come from ‘Architect’ background but always loved singing. It all began eventually because I studied about buildings, designs and construction but had a good hobby of writing poems or quirky lines which made me to think to get into music industry. I tried experimenting with my voice when I was young and as I had my writing samples and talent to write poems which provoked me to sing professionally also. My writings needed just a touch of tunes or surr. And when I saw today’s generation enjoying music be it of any kind that encouraged me to continue with my decision of entering into singing. All I needed is music, tunes and raps which were combined with my song Saturday Saturday and you see; it went on to become a blockbuster hit amongst youth and everyone.Singing came naturally to me and I’ve spent years honing that ability.  Also Read – ‘Playing Jojo was emotionally exhausting’On what basis do you pen down your songs?My lyrics are very conversational, and I write them to cater to the youth and the way that youngsters talk today and my music style is mostly R&B.My first sad song Tere Liye’ it’s a slow track and was in the movie Delhi Wali Zalim Girlfriend. This track was not to sale it out and nor was meant to be released, the song was one of the incidents of my life which turned out to be a fallout in a relationship and I wrote this song when I was in Shimla. At that time I wrote two songs one is Tere Liye and other one is 2 AM which is soon to be released.  Also Read – Leslie doing new comedy special with NetflixTere Liye was bought by T-Series after they listened to my track which was set as my ringtone. Also another song which came was Billionaire and was based out of my real life story which lately Raftaar gifted me at the launch.How did ‘Indeep Sound’ happen?I used to listen to international and bollywood music both, then I try recreating bollywood music by putting my own music in it. After that I started writing songs and then I came up with Saturday Saturday, this happened when I was teasing my friend one day who had come from Punjab and was excited to see the nightlife of Delhi. Uski ek baat hoti thi, every Saturday party karni hai! I used to tease her ki Saturday Saturday karti raheti hai. I made a rough dummy of that track and my friend encouraged me to release it. Then I met Badhsah bhai and did it professionally.   Tell us about your Bad Wali Feeling song.This is song has an adult certificate and the video content is strictly 18+. This song is in another genre of RNB mix only like Saturday Saturday was first house music.For this particular song, we had shot the video three times as I was not satisfied with the kind of video I wanted. At last the final video was shot in Dubai with a lot of entertainment in it.Sharing the platform with your contemporary artists like Yo Yo Honey Singh and Badshah how do you think the competition will affect you?As such there is no competition and nor do I take any singer as my competition. Every artist as his own style of singing and genre of music is also different. Secondly, more than profession it’s my passion and if we see the competition is more in the profession as compared to passion. Moreover, I know my style of singing is the future and the kind of music I produce will be the future.What are the other aspects of life which interest you?Music, cars and bikes are my interests for which I can go to any lengths. Also I possess a large classy collection of the same. I am an extreme junkie and have an attitude to try sports and also I’m willing to try my hand at new things. Though my interests keep changing, ultimate passion is luxury and music and yes I am constantly on the hunt for something bold and adventurous.What are your future projects? I am coming up with a new track Bad Wali Feeling which is an 18+ track. Also since my Sikh fans are saying that I am not wearing turban in the videos so for them I am coming up with a special track Singh honde Badhsah te Kaur hondi Queen. This is a pure bhangra track which has Punjabi culture in it. Besides this, my new track 2 AM which is very close to me will be out soon. Also, for the first time I will be featuring with Sunny Leone in the title track Paheli Bari Ki of the movie Tina and Lolo. This will be my third track in bollywood after Saturday Saturday and Tere Liye.I was not doing live concerts and performances for a long time but now I am planning them. I will be soon seen performing live in concert at the CEOL Festival at Metro Walk, Rohini.last_img read more


Divya Khosla Kumar turns showstopper at LFW 2016

first_imgThe Hindi film industry has a lot of versatility in terms of talent and same is the case with the fashion industry. These two however find a way to collaborate and promote each other. To showcase the latest collection, the talented actor, director and producer Divya Khosla Kumar walked the ramp for ‘Garo’ by Priyangsu and Sweta on the final day at the Lakme Fashion Week 2016. She wore a floor length kalidar with patchwork and embroidery detailed peplum top with sharara. Also Read – ‘Playing Jojo was emotionally exhausting’Divya Khosla Kumar said: “It is a beautiful dress which is wearable at any occasion. It is a very light weight outfit and the designers Priyangsu and Sweta of ‘Garo’ have made the entire collection with material which is so easy to wear, soft and easily likable. As a woman you need to be very presentable and ‘Garo’ has something to offer that you should not miss”.The collection theme was ‘Femmes di Tahiti’ which is inspired by native tahitian prints, colours and motifs. It has incorporated the stunning natural beauty, beautiful floral landscapes and bohemian style of tahitian women with an eclectic French Polynesian flavour. “We are elated to be a part of the Lakme Fashion Week and it has been a wonderful experience. We wish to be a part of Lakme Fashion Week in many more seasons to come,” said the designers Priyangsu and Sweta.‘Garo’ by Priyangsu Maji and Sweta Tantia, launched in Kolkata is an Indian luxury brand that creates and designs contemporary Indian wear for women.last_img read more


Man stabbed to death by son in North Dinajpur

first_imgKolkata: Ranjit Das (52), a resident of Indran village under Itahar police station in North Dinajpur, was stabbed to death inside his house on Sunday night.Locals have alleged that the victim’s son Rajesh might have killed him to take revenge on his mother’s death. It was also stated that Ranjit had killed his wife a few years ago. Police have started a detailed probe to ascertain the exact cause behind the murder. According to the preliminary investigation, police also suspect that the victim was killed by his son. Also Read – 3 injured, flight, train services hit as rains lash BengalThe villagers told police Rajesh often got involved in fights with his father over the death of his mother, Rupa Das. The woman was murdered five years ago. Ranjit was arrested on the charges of killing his wife and later released on bail. It was learnt that when the incident had occurred, Rajesh lived in Delhi for professional reasons. After returning home, a year ago, he came to know about this father’s involvement in his mother’s death. The equation between Rajesh and his father had changed since then but nobody in the locality could expect that it would lead to such a crime. It was learnt that the accused son hit his father’s head with a sharp weapon following a quarrel. The injured father was taken to a hospital in Raigunj on late Sunday night. He succumbed to his injuries at the hospital on Monday morning. The accused, Rajesh, has been absconding since the incident took place. Police have started a probe into the incident and are raids are being conducted to nab the culprit.last_img read more