Graphene quantum dot may solve some quantum computing problems

first_img Scientists discover coal-derived ‘dots’ are effective antioxidant 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. Ensslin, along with fellows at the Solid State Physics Laboratory, Stampfer, Güttinger, Molitor, Graf and Ihn, believe that they can use electron spins from a tunable graphene quantum dot to create qubits, the building blocks of a quantum computer. These graphene-based qubit could rectify some of the problems found with gallium arsenide. As a first step they present a graphene single electron transistor in Applied Physics Letters: “Tunable Coulomb blockade in nanostructured graphene.”One of the main problems with spin-based quantum computers, Ensslin explains, is that spins won’t keep their direction indefinitely. “Spin is up or down in a magnetic field,” he tells PhysOrg.com, “which can be identified with zero or one.” He explains that in a quantum set up, it can even be both simultaneously. But spin states don’t always stay in the same state. “They interact with different parameters in their environment, and that can change things.” Electrons have their own spin, and the nuclei of neighboring atoms also have spin. Eventually, the electron spin used in quantum computing will couple with other nuclear spins, causing a breakdown of coherence in the quantum system.“Graphene turns out to be a material which is expected to overcome this,” Ensslin says. He is careful to explain that even though he and his peers have created a graphene quantum dot, extrapolations of how it would work in a quantum computer are still at the theory stage. “When you look at this theoretically, you find that 98 percent of carbon has no nuclear spin. This means that the coupling between nuclear spins and electron spins would be strongly reduced.”The expectation is that this would be a nice system to “realize a spin qubit, provided one can make a quantum dot in graphene – which has now been done – and provided one finds ways to manipulate individual spins in this system.”Ensslin calls the work the Zurich team has done a first step. “We have shown that a quantum dot made from graphene is possible. Basically it’s a proof of principle.” But there are subsequent steps that need to be taken as well. The quantum dot needs to be tested, and it needs to be made smaller, so there are challenges ahead.“We need to be able to distinguish between individual electrons,” Ensslin says. “Right now we don’t know how many there are.” The whole point is to figure out how to get the quantum dot to a point where there are no more than one or two electrons.Another issue is the edge, Ensslin says. “In contrast to semiconductors, which generally have smooth edges, graphene has a rougher edge. Theoretically, the edges play a role in graphene. It will be important to figure out where the atoms are on the edge, and to gain experimental control over the edge. This is crucial to control the electrons.”Ensslin believes that if this can be done, perhaps a couple of years into the future, it will be possible to test the fitness of a graphene quantum dot for spin-based quantum computing. “ There is no fundamental reason why it shouldn’t work.”Copyright 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. Around the world, many scientists are working on various models of a quantum computer. One of the proposed models is a quantum computer that makes use of electron spins. And while quantum dots in gallium arsenide have been used to accomplish the first steps in this direction, there are certain problems that come with a spin-based quantum computer that uses gallium arsenide. Klaus Ensslin, a scientist at the Solid State Physics Laboratory in Zurich, believes that he and his colleagues may have found a new approach.center_img Citation: Graphene quantum dot may solve some quantum computing problems (2008, January 15) retrieved 18 August 2019 from https://phys.org/news/2008-01-graphene-quantum-dot-problems.html Explore furtherlast_img read more

Amazons Bezos envisions airbag phone files patent

first_img As one smartphone scenario goes, the user drops the phone. Whoops, says the safety monitoring system, this device is no longer in contact with the user. The approaching surface is measured and the velocity is determined. Does the risk of damage exceed the threshold? If so, here comes the airbag to be deployed, and it’s the airbag, not the poor device, that makes first contact with the surface.When the news hit that Bezos had filed a patent for phones with airbags, a number of responses from writers in the blogosphere admitted disbelief, perhaps not unrelated to bearing witness to the sting of discovering that the ‘Internet Explorer users are more stupid’ report was a hoax. The application states conditions that make such a proposal appear practical considering the heavy use of mobile devices and the need to protect them from damage. “These portable devices are sometimes vitally important to the user as they often contain data that is related to the user’s work and personal life,” says the application. That data might include private data difficult or nearly impossible to replace.Bezos studied electrical engineering and computing science at Princeton, and also worked as a financial analyst. That, leave alone his ascent as leader of click-and-buy Amazon, suggests a scientist who knows how to market ideas. His business case in the application is as interesting as his technical description.“With the number of cellular phones in use exceeding several billion and repairs typically exceeding $25, the costs of damage and loss of cellular phones amounts to billions of dollars per year,” says Bezos. He also notes in the application, “At least one report claims 1 out of 3 cellular phones are damaged or lost in the first year of ownership.”Whatever direction the patent application takes, or whoever compares Bezos more to Don Quixote than Thomas Edison, Bezos is not likely to feel demolished. As he once told new students at Princeton, “Failure is an essential component of innovation.” © 2011 PhysOrg.com (PhysOrg.com) — A U.S. patent application was filed in February 11, 2010 bearing the names of Amazon founder Jeff Bezos and Amazon VP Greg Hart but was discovered this week by Geekwire. According to their patent application titled “Protecting Devices From Impact Damage,” smartphones will get airbags as a safety precaution in case their users drop the phones or they fall accidentally. The two patent-seekers are proposing the system and method not just for the smartphone but for a range of mobile devices that nobody likes to drop, such as audio players, cameras and pagers. Bezos and Hart’s patent filing has Illustrations and flowcharts to further explain their “removably attachable damage avoidance system.” Amazon CEO: Color Kindle ‘still a long way out’ Explore furthercenter_img Citation: Amazon’s Bezos envisions airbag phone, files patent (2011, August 14) retrieved 18 August 2019 from https://phys.org/news/2011-08-amazons-bezos-envisions-airbag-patent.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. More information: appft.uspto.gov/netacgi/nph-Pa … 30&RS=DN/20110194230last_img read more

Research group finds creating boundaries key to reducing ethnic violence

first_img Explore further Maps of Switzerland showing the 2000 census proportion of (A) linguistic groups, (B) Catholic and Protestant (Mercator projection). Image: arXiv:1110.1409v1 More information: Good Fences: The Importance of Setting Boundaries for Peaceful Coexistence, arXiv:1110.1409v1 [physics.soc-ph] arXiv:1110.1409v1 [physics.soc-ph]AbstractWe consider the conditions of peace and violence among ethnic groups, testing a theory designed to predict the locations of violence and interventions that can promote peace. Characterizing the model’s success in predicting peace requires examples where peace prevails despite diversity. Switzerland is recognized as a country of peace, stability and prosperity. This is surprising because of its linguistic and religious diversity that in other parts of the world lead to conflict and violence. Here we analyze how peaceful stability is maintained. Our analysis shows that peace does not depend on integrated coexistence, but rather on well defined topographical and political boundaries separating groups. Mountains and lakes are an important part of the boundaries between sharply defined linguistic areas. Political canton and circle (sub-canton) boundaries often separate religious groups. Where such boundaries do not appear to be sufficient, we find that specific aspects of the population distribution either guarantee sufficient separation or sufficient mixing to inhibit intergroup violence according to the quantitative theory of conflict. In exactly one region, a porous mountain range does not adequately separate linguistic groups and violent conflict has led to the recent creation of the canton of Jura. Our analysis supports the hypothesis that violence between groups can be inhibited by physical and political boundaries. A similar analysis of the area of the former Yugoslavia shows that during widespread ethnic violence existing political boundaries did not coincide with the boundaries of distinct groups, but peace prevailed in specific areas where they did coincide. The success of peace in Switzerland may serve as a model to resolve conflict in other ethnically diverse countries and regions of the world. Citation: Research group finds creating boundaries key to reducing ethnic violence (2011, October 13) retrieved 18 August 2019 from https://phys.org/news/2011-10-group-boundaries-key-ethnic-violence.html © 2011 PhysOrg.com Switzerland, the very modern symbol of a peaceful country, might have gone another direction the team finds, were it not for the way the differing groups (French, German and Italian) and religions (Catholic and Protestant) have been physical grouped within the borders of the small country.Those of German descent make up the largest group, taking up most of the north, central and eastern parts of the country while those with Italian backgrounds live predominately in the south; those of French descent have settled mainly in the west. Not surprisingly, those of the Catholic faith live predominately in the southern and middle parts of the country, due to the influx of those of Italian descent, while those of the Protestant faith live mainly in the rest of the country.To find out how all these differing groups found a way to get along, the team looked at the geography of the country (mainly mountains and lakes) and how its regions are subdivided. In Switzerland, areas of the country are partitioned into what are known as cantons, which are similar to states in other countries except that each has much more autonomy than is usual. After careful study, the team found that the main reason the groups all manage to get along, is because they are separated from one another. Each canton is comprised of almost all the same types of people, essentially ruling themselves, thus, there is very little overlap. Other areas are separated by lakes or mountains. The end result is that people of differing cultures very seldom run into one another (except in the larger cites of course) and thus friction is averted. The one exception appears to be a little area north of Bern, where violence did erupt in the 1970’s. That problem was apparently fixed by simply redistricting the cantons in that area.One problem with the study of course is that it doesn’t take into account the history of the land itself. The problems with India and Pakistan, for example, or with Israel and the rest of the Middle East aren’t likely to be solved by building better borders. But, nonetheless, the study does shed a rather bright light on the idea that simple separation can sometimes lead to peace. Not unlike how a schoolteacher might solve a problem between two quarreling youngsters. (PhysOrg.com) — History is filled with examples of ethnic violence, the type that erupts when people with differing cultures attempt to live side by side. The Middle East comes to mind, as does Northern Ireland or Yugoslavia. What’s not so common are studies done that show what sorts of things actually work to prevent problems when people of dissimilar backgrounds live next door to one another. Thus, a new study done by Yaneer Bar-Yam and his team at the New England Complex Systems Institute, appears to be particularly relevant. He and his colleagues, describe in their paper on the preprint server arXiv, how a study they’ve done of the ethnically diverse country of Switzerland, shows that political and geographical boundaries have served to keep the peace between the different groups. Earth from space: Central Europe 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

Subhabrata Majumdar who kept mothers corpse in freezer gets bail

first_imgKolkata: Subhabrata Majumdar who had put his mother’s corpse in a deep freezer for three years got a bail on Friday day.Majumdar was released on a bail bond worth Rs 500. The judge has instructed the police to treat him in a state run hospital.The doctors at the Institute of Psychiatry said he was suffering from Schizophrenia. He has “auditory hallucination” and often heard “voices of the Russian and German consulates talking to him.” The patients suffering from auditory hallucination often hear voices from unknown persons who give them instructions. The voices even use filthy words. Also Read – Heavy rain hits traffic, flightsMajumdar’s mother died three years ago in a hospital. Instead of cremating her, Subhabrata brought her corpse back home and kept it in a commercial chest freezer.The doctors said Subhabrata had acquired profound knowledge in preservation of bodies particularly the technique used by the Russians in the 1970s. In a bid to study books, he learnt Russian language. He can talk on different things. Police have seized many books on human Anatomy and Physiology from his residence. Also Read – Speeding Jaguar crashes into Merc, 2 B’deshi bystanders killedThe doctors said his body language and attitude suggest that he is suffering from “non affective psychosis.” During interaction, the doctors found that he is talking incoherently at times.He was taken to the Pavlov Institute where he was put up. The Psychiatrists will talk to him later. He will be put under observation and his behavior will be closely monitored and studied.During interrogation, Subhabrata told the police that he thought that his mother would come back to life. Police will interrogate the bank employees to find out the reasons Subhabrata had put forward to express his mother’s inability to come to the bank to withdraw pension and who had signed the documents which are submitted annually to the bank by pension holders.Cops have found another deep freezer of similar size at the residence. Preliminary investigation had revealed that his father did not know anything about his son’s misdeeds and that her corpse was kept inside the deep freezer.last_img read more

Balurghat Cops body found floating

first_imgBalurghat: A policeman’s body was found floating in Atreyee at Balurghat’s Kalyanighat on Wednesday. The deceased has been identified as Babun Hela (35). He was a resident of Kalyanighat.Police said the deceased was posted at police commissionerate in Siliguri. Police rushed to the spot after being informed by the locals who found Babun floating in Atreyee in the morning. Police rescued the body and sent it for post-mortem.A probe has also been initiated by police after the locals informed them that the deceased cop was an expert swimmer and he used to swim regularly while staying in Balurghat. Babun got married about four years back. However, his wife resides with the only girl child in Kolkata with her parents. Babun stayed with his elder brother and sister-in-law when he visited Balurghat.The deceased was on a leave over the past few days and had come to Balurghat. On Tuesday around 10 in the morning, he went to take a bath in the river and didn’t return the whole day. His body was found floating on Wednesday.last_img read more

Steps taken to bolster security ahead of Maheshtala bypoll

first_imgKolkata: All steps have been taken to ensure that the by-election in Maheshtala Assembly constituency in South 24-Parganas passes peacefully, without any untoward incident.The by-election is going to be held at 283 booths spread across the 44 sq km area of the Assembly constituency, where the poll is going to start from 7 am on Monday morning and continue till 5 pm.In a bid to ensure that the election passes peacefully, a total of nine companies of Central forces have been deployed at the Assembly constituency, which became vacant with the death of two-time MLA Kasturi Das in February. Also Read – Heavy rain hits traffic, flightsTrinamool Congress has fielded the sitting Chairman of Maheshtala Municipality Dulal Das, whereas CPI(M) has fielded Pravash Chodhury. Congress has not fielded its candidate due to its alliance with CPI(M). Meanwhile, BJP’s candidate for the by-election is Sujit Ghosh.There will be paramilitary forces in each of the polling premises, along with a policeman. Besides ensuring security in the polling stations, steps have also been taken to ensure that no untoward incident takes place in any part of the Assembly constituency area. Also Read – Speeding Jaguar crashes into Merc, 2 B’deshi bystanders killedThere will be mobile patrolling vans that will keep moving around the area to ensure proper vigilance when the election will go on. At the same time, there will also be quick response teams (QRT) that will remained stationed at strategic locations and they will be directed to move immediately to tackle a situation if deterioration of the law and order situation comes to notice at any place. There was patrolling at different parts in the area since morning and polling personnel were also found busy making all necessary arrangements to start the election on time in all the booths. There will also be VVPAT machines.There is a total of 2,48,754 voters, including 1,27,178 male and 1,21,576 female citizen, who will be exercising their power on Monday, while the counting is scheduled to be held on May 31. There will also be necessary security arrangements to avoid any untoward incident on the day of counting as well.last_img read more

Bengalimedium students given raw deal says Mamata

first_imgKolkata: Chief Minister Mamata Banerjee expressed her immense dissatisfaction over the way Bengali-medium students have been deprived of in the National Eligibility cum Entrance Test (NEET).Chairing a meeting at Nabanna on Tuesday, she said: “I am offended as our students have not got a better opportunity. I heard there were issues with the question paper. The English and Bengali question papers were different.”Criticising the Centre for the same, the Chief Minister also added: “They are not giving priority to the regions. Students from the states are getting deprived. The matter has to be taken up with the MCI and we plan to take it up with the Centre as well.” Also Read – Heavy rain hits traffic, flightsIt may be mentioned here that the Chief Minister had written to Union Human Resource Development minister Prakash Javadekar drawing his attention to the question paper debacle that occurred mainly in the Bengali translation. Despite her intimation, no steps have been taken in this regard so far.As a result of the incident, students from the state who had opted for Bengali as the medium of language performed miserably in the NEET the result of which was published on Monday. A student has already moved Calcutta High Court seeking its intervention regarding the question paper. The Calcutta High Court sought clarification from the Centre and also the CBSE on how the Bengali translation of the question paper was full of so many errors and also asked the Centre to reserve a seat for the petitioner who filed a writ petition with the court. Also Read – Speeding Jaguar crashes into Merc, 2 B’deshi bystanders killedThe Chief Minister asked senior health officials to take up the NEET issue with the Centre so that the Bengali-medium students would not be deprived to study MBBS. While giving a detailed account of what the state government has done in the health sector, Banerjee said seats have been increased from 1,300 to 2,900 after the present government came to power. Mother and child hubs have also been set up. There is, however, an urgent need to increase the number of doctors. “There is a requirement of more doctors and sisters in the hospitals and we want that the number of doctors to increase. Many of the doctors go out creating a dearth in the state. There is a need of neuro-surgeons as well,” the Chief Minister maintained.”The dearth can only be addressed if the number of doctors is produced in the state. The issue was never looked into before. We have overcome the issue to a great extent and it will take some time to address the deficit. Doctors are the assets and they have to cater to huge number of patients in hospitals like SSKM Hospital, Calcutta Medical College and Hospital, NRS Medical College and Hospital, RG Kar Medical College and Hospital where more than 2 lakh patients turn up in Out Patient Department (OPD) each in a month, she said.last_img read more

Bombs explode in Burdwan school 3 children injured

first_imgThree school children were injured, two of them critically, in a bomb explosion at a village school in West Bengal’s Burdwan district on Friday. Police said several children had climbed the roof of Dahuka Girish Primary School at Khandaghosh, which was closed on account of EId-ul-Azha, to help their parents dry paddy.A child found a bag full of bombs stored at a corner of the roof. Mistaking the round bombs for balls, he threw one on the field near the school, where some more children were playing, the police said. Also Read – Punjab on alert after release of excess water from Bhakra damThe bomb exploded with a loud sound and injured the three, including two siblings – a brother and a sister aged four years and five years respectively. Another injured was a teenaged girl of class seven.The three were rushed to a medical facility at Khandaghosh from where the siblings were referred to Burdwan Medical College and Hospital as they were critically injured. Later, the police found two more live bombs from the school roof. Investigations are on, the police added. Also Read – Union Min doubts ‘vote count’ in Bareilly, seeks probeOne killed, two injured in Kolkata blastOne man was killed and two others injured in a crude bomb explosion at an abandoned factory site here on Friday, police said. Sanjeev Das and his co-workers were cleaning an abandoned factory site in Cossipore in north Kolkata when a crude bomb exploded around 3 pm Das died while the two others were injured.“We are carrying out further investigation into the explosion. The site was completely abandoned. We are examining the site now,” said Deputy Commissioner of Police (North), Subhankar Sinha Sarkar.last_img read more

Medical board formed at NRS Hospital to treat needle case victim

first_imgKolkata: A medical board has been formed at NRS Medical College and Hospital for the treatment of the Krishnanagar girl who had swallowed 10 needles.The doctors have successfully removed all the needles from Aparupa Biswas’s throat on 31 July. The patient’s condition is stated to be serious and she has been kept in the Intensive Care Unit (ICU) of the hospital. The hospital authorities have formed a medical board for her treatment. According to the hospital sources, the patient has developed some psychological problems and has been kept under observation. Also Read – Rain batters Kolkata, cripples normal lifeAccording to the hospital authorities, many tests are yet to be conducted on the patient to ascertain her problems. A senior official of the hospital said special attention has been given to her.A student of class VIII from Krishnanagar Akshay Vidyapith had swallowed as many as 10 needles. She complained of pain following which her family members took her to a local doctor, who prescribed some medicine but her condition did not improve. The family members initially thought that she might have caught cold. She was later taken to NRS Medical College and Hospital on 30 July. After conducting an X-ray, the doctors found that needles are stuck on her throat. Doctors gave a fresh lease to the 14-year-old girl by removing the needles from her throat through an operation that lasted for more than three hours.The doctors are not yet sure as to how and why the girl had swallowed 10 needles. It is suspected that she might have been involved in black magic after she lost her elder brother three years ago. She had been under depression since the death of her brother. The medical board is been examining the patient to ascertain the exact cause.last_img read more

SIMI member Abu Faizal gets life sentence for cops murder

first_imgA special trial court here on Saturday sentenced Abu Faizal, a member of the banned Students Islamic Movement of India (SIMI), to life imprisonment after finding him guilty of killing a police constable in 2009.Faizal had been convicted by the additional sessions judge B S Bhadoria on Friday. The court also awarded three years’ imprisonment to co-accused Mahtab after finding him guilty under the Arms Act for supplying a weapon to Faizal which was used in the crime, said Special public prosecutor Naresh Gupta. Also Read – Punjab on alert after release of excess water from Bhakra damFaizal has been found guilty for the murder of constable Sitaram Yadav in Khandwa district in 2009. Faizal, who attended the hearing from jail through video conference facility, lost his cool and shouted after the judge pronounced the verdict on Friday. On Saturday also he attended the hearing through video conference. Faizal and four others shot Yadav dead. Three of them are still absconding while one died, Gupta said.last_img read more