Operating quantum memory at room temperature

first_img Explore further Citation: Operating quantum memory at room temperature (2008, August 25) retrieved 18 August 2019 from https://phys.org/news/2008-08-quantum-memory-room-temperature.html Quantum dots, along with quantum wires, have been attracting notice over the past decade as possible building blocks of quantum information processing. Indium arsenide quantum dots (InAs) can be used for memory operations in devices made from gallium arsenide and aluminum gallium arsenide (known as GaAs/AlGaAs devices). The problem is that at room temperature – the experiments are usually done at lower temperatures, the memory operation of these devices suffers, unless there are multiple quantum dot layers. Digitally programmable perovskite nanowire-block copolymer compositescenter_img That is changing now, thanks work done by a team of scientists at Würzburg University in Germany. “Memory operated at room temperature, and with only a single layer quantum dot layer, is important because it can be used in every day life,” Lukas Worschech, a member of the team at Würzburg tells PhysOrg.com. The work done by the team, which includes Müller, Heinrich, Höfling and Forchel, appears in Applied Physics Letters: “Room temperature memory operation of a single InAs quantum dot layer in a GaAs/AlGaAs heterostructure.”For quantum information processing, some sort of memory operation is necessary. One of the ways of realizing a memory device is to use quantum dots coupled to a transport channel. Memory (nonvolatile – such as flash memory) is realized when the charge state of the quantum dots control the system’s threshold. A floating gate is used to manage the threshold voltage. In GaAs/AlGaAs devices, the charge storage that is needed can be induced optically as well as electrically, which increases their usefulness and compatibility with different electronic and optoelectronic devices.“Until now, though,” Worschech explains, “low temperatures were needed with single layer quantum dot. Our idea was to create a system that could work under increased temperatures. Otherwise, you always have to put your samples in cryostats, and use long wirings. This makes it harder to extract all the information you want.” The Würzburg team suggests that with the InAs quantum dot functioning as a floating gate, the memory could be operated at room temperature. “From this structure, field emission is reduced drastically and we are able to observe the memory effect at room temperature.”One of the more interesting things about this set-up is that the InAs quantum dot is actually self-assembling. “The trick here is that the material does not match directly to the gallium arsenide. You do not have to structure them.” However, it can be difficult to control where these InAs quantum dots end up. “They are randomly distributed,” Worschech says, “you cannot say in a lateral field where they are placed.”Other scientists, though, have been working on this issue. “Through etching – making small holes at pre-defined sites – it turns out that indium arsenide growth can be controlled laterally,” Worschech points out. “Others have been working on this, and we would like to see our method combined with this lateral positioning that is being studied.”“This field of quantum dots is being intensely studied right now,” Worschech continues, “for use in quantum computers and sensors. Quantum cryptography is another field that would benefit from this work. It is also interesting for optical electronics. Our work may sever as an inter-connect for different applications.” Copyright 2007 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. 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

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Study shows songbird prefers singing in harmonic series similar to humans

first_img Citation: Study shows songbird prefers singing in harmonic series similar to humans (2014, November 4) retrieved 18 August 2019 from https://phys.org/news/2014-11-songbird-harmonic-series-similar-humans.html More information: Emily L. Doolittle, Bruno Gingras, Dominik M. Endres, W. Tecumseh Fitch. Overtone-based pitch selection in hermit thrush song: Unexpected convergence with scale construction in human music.  Proceedings of the National Academy of Sciences (PNAS). November 2014. www.pnas.org/cgi/doi/10.1073/pnas.1406023111 AbstractMany human musical scales, including the diatonic major scale prevalent in Western music, are built partially or entirely from intervals (ratios between adjacent frequencies) corresponding to small-integer proportions drawn from the harmonic series. Scientists have long debated the extent to which principles of scale generation in human music are biologically or culturally determined. Data from animal “song” may provide new insights into this discussion. Here, by examining pitch relationships using both a simple linear regression model and a Bayesian generative model, we show that most songs of the hermit thrush (Catharus guttatus) favor simple frequency ratios derived from the harmonic (or overtone) series. Furthermore, we show that this frequency selection results not from physical constraints governing peripheral production mechanisms but from active selection at a central level. These data provide the most rigorous empirical evidence to date of a bird song that makes use of the same mathematical principles that underlie Western and many non-Western musical scales, demonstrating surprising convergence between human and animal “song cultures.” Although there is no evidence that the songs of most bird species follow the overtone series, our findings add to a small but growing body of research showing that a preference for small-integer frequency ratios is not unique to humans. These findings thus have important implications for current debates about the origins of human musical systems and may call for a reevaluation of existing theories of musical consonance based on specific human vocal characteristics.Press release (Phys.org) —A team of researchers with members from Germany, the U.S. and Austria has found that male hermit thrush appear to sing following a harmonic series similar to the way humans produce music. In their paper published in Proceedings of the National Academy of Sciences, the team describes how they studied bird songs recorded by various people over the past half century and then compared the way the birds sang to the way people create music. Hermit Trush. Credit: Daniel Berganza/Wikimedia 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. Male songbirds don’t have to be studs to find a matecenter_img When human beings create music, whether it’s singing, or using instruments, we tend to follow a harmonic series, which is where notes that follow a base note are multiples of that base note—doubles, triples, etc. Generally an entire piece of music is made from the notes that belong to scales based on a particular note—the C Major scale, for example, starts with the note C, and the music for such a scale would generally be in the key of C. In this new effort, the researchers have found that at least one species of songbird adheres to roughly the same set of rules when creating and performing its songs—which would make it the first time any other animal besides humans have been found to do so.The researchers discovered this unique attribute of the male hermit thrush by analyzing song samples found in Ohio State’s Borror Laboratory—researchers there have been collecting audio samples for the past fifty years. All told, they looked at 71 different songs made by 14 individual males. They found that 57 of those songs, when analyzed mathematically, followed a harmonic series—a much higher percentage than can be attributable to chance. They also noted that only 5 percent of the songs consisted of what appeared to be random noise making.The researchers noted that the anatomy of the songbirds’ throat clearly allows for playing a far wider range of notes, thus, the birds appear to be choosing notes from a particular scale when singing their songs, allowing them, like us humans to remain on key. This suggests, they add, that song-making in humans is likely more biological than due to custom. Journal information: Proceedings of the National Academy of Sciences Explore further © 2014 Phys.orglast_img read more

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Neolithic pottery sherds from China reveal alcoholic beverage production techniques

first_img Explore further Human beings have been making alcoholic beverages for approximately 13,000 years, and they have been doing it in different ways depending on what resources they had available to them—the people living in Neolithic China, in what is now the Wei River Valley, had rice, millet and several other ingredients that allowed them to make fermented beverages. In this new effort, the researchers have found evidence showing that people made alcoholic beverages in at least two ways.The pottery sherds the researchers tested were dated to approximately seven to nine thousand years ago. They found traces of fungi, starches and plant tissue—ingredients for brewing fermented beverages. The sherds and the shape of the pottery they came from indicate that the Neolithic people were making their alcoholic beverages with two methods. One was to allow grains to sprout, which frees sugars in the plant. The other method was more complicated, involving fungi, herbs and grains to make a starter called qū—it allowed for “simultaneous saccharification and fermentation.”The researchers note that the early drink makers also designed and made pottery vessels that promoted fermentation—small-mouthed with wide sides and thin necks allowed for sealing to keep out fresh air, which encouraged anaerobic brewing processes. They also point out that neither process likely resulted in very strong drinks. They also claim the early evidence of fermenting drinks suggests that the desire to create such beverages might have been part of the push toward the development of agriculture. They believe drinking alcohol likely became linked with social and religious activities, and might have even bestowed some degree of status on those able to provide it to others. Alcoholic beverages are frequently considered migraine triggers A group of pottery vessels studied, with some analyzed for food traces, in the Baoji Museum in Shaanxi province, China. Credit: Li Liu Citation: Neolithic pottery sherds from China reveal alcoholic beverage production techniques (2019, June 4) retrieved 18 August 2019 from https://phys.org/news/2019-06-neolithic-pottery-sherds-china-reveal.html A team of researchers from Stanford University, Zhengzhou University, the Chinese Academy of Social Sciences and Shaanxi Provincial Institute of Archaeology has learned more about the ways Neolithic people in China made alcoholic beverages by studying pottery sherds from that era. In their paper published in Proceedings of the National Academy of Sciences, the group describes their study of residue left behind on fragments of pottery. A globular jar fitted with a funnel-steamer in the Baoji Museum in Shaanxi province, China. Credit: Li Liu. More information: Li Liu et al. The origins of specialized pottery and diverse alcohol fermentation techniques in Early Neolithic China, Proceedings of the National Academy of Sciences (2019). DOI: 10.1073/pnas.1902668116 © 2019 Science X Network Journal information: Proceedings of the National Academy of Sciences 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

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For the mind and soul

first_imgOn the auspicious occasion of Maha Shiv Ratri witnessed an musical treat. The 51st Mahashivratri Sangeet Sammelan 2015 saw the performance by santoor maestro and music composer Abhay Rustum Sopori. He was accompanied by Ustad Rafiuddin Sabri. The event further was carried by Pt Salil Bhatt on Satwik Veena and Ustad Akram Khan on Tabla. The sammelan was held at Azad Bhawan Auditorium, ICCR on February 17. Abhay Rustum Sopori is the youngest Santoor maestro and the youngest classical musicianto compose and conduct orchestras and folk ensembles. He has also been the youngest recipient of all the awards that he has received. Abhay was born in Srinagar and inherited a profound sense of music from his fabled Sufiana Gharana of Kashmir – the exclusive traditional Santoor family – with its roots spanning nine generations over more than 300 years. Abhay continues to innovate and experiment with the Santoor further extending its dimension. In keeping with his lineage he has established the concept of Gayan-Vadan Baaj in the Indian classical system and introduced the Open String Concept on the Santoor together with the Enhanced Sustain Technique. He has revived the old Sufiana Tarana compositions of his predecessors and adopted them in the Indian Classical scenario and also composed and introduced new Khayal compositions based on Sufi Saints of Kashmir.last_img read more

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Fourfold jump in infra devp budget since 2011 Mamata

first_imgKolkata: In a bid to ensure overall development of the state, the Mamata Banerjee government has increased the expenditure for developing physical infrastructure “four-fold”, since 2011.This is the first time when the state has witnessed such a huge investment for development of infrastructure.The Chief Minister tweeted on Sunday: “Infrastructure development is going on in a rapid pace in Bengal. In fact, expenditure on physical infrastructure in the state has increased almost 4-fold since 2011.” Also Read – Heavy rain hits traffic, flightsGiving detailed information on the expenditure carried out by her government, the Chief Minister stated in the tweet: “Recently, new infrastructure projects including flyovers, rural and urbandrinking water, roads and bridges, power, affordable housing, irrigation etc worth Rs 18,000 crore, have beensanctioned by our government.”She also tweeted: “This is in addition to the Rs 25,755 crore budgetary allocation for capital expenditure, for the current financial year. These will open up huge investment opportunities and generate employment in the state…” Also Read – Speeding Jaguar crashes into Merc, 2 B’deshi bystanders killedAfter coming to power, Banerjee had given equal stress on the development of both the rural and urban parts of the state. Development of roads and bridges has ensured better connectivity between different parts of the state.At present, there are several projects which are going on and include major projects like construction of the new Iswar Gupta Setu on river Hooghly. A project has also been taken up to construct flyovers at different parts of the city to ensure fast movement of vehicles. Recently, the Chief Minister inaugurated the 4.4 km long Garden Reach flyover, that has made the journey from Brooklyn crossing near Ramnagar to Majherhat railway station hassle-free.Most importantly, the state now has one of Asia’s biggest convention centres, Biswa Bangla Convention Centre, at Rajarhat, where all sorts of major events including Bengal Global Business Summit is organised.Besides developing the infrastructure that helps attract investment in the state, the Mamata Banerjee government has also developed cultural and sports centres. Recently, the announcement of the decision to develop a Khel City at Dumurjola in Howrah has been made.The problem of water crisis has become history at most places and the work to ensure the same in the remaining areas, where people had been suffering due to poor water supply for decades, is going on in full swing.last_img read more

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Antibody may help old people regain muscle power

first_imgA newly created antibody could treat the decline in muscle mass and power associated with ageing, show results of a phase-two trial by an international research team.The myostatin antibody treatment improved muscle power in the elderly, as indicated by improvements in the ability to climb stairs, walk briskly and rise repetitively from a chair, the findings showed.“Myostatin is a natural protein produced within the body that inhibits muscle growth,” said one of the researchers Stuart Warden from Indiana University-Purdue University Indianapolis, US.  Also Read – ‘Playing Jojo was emotionally exhausting’“It has been hypothesised for some time that inhibition of myostatin may allow muscle to grow, resulting in improved muscle mass and physical performance. The current study confirms these beliefs,” Warden said. In the study, injections of a myostatin antibody, made by US-based Eli Lilly and Co, over a 24-week period resulted in an increase in lean (muscle) mass and improved performance on tasks requiring muscle power in patients older than 75 with low muscle strength, low muscle performance and a history of falling.  Also Read – Leslie doing new comedy special with Netflix“This is the first study to show that myostatin antibody treatment improves performance on activities requiring muscle power,” Warden said. “Muscle power’ refers to the ability to generate muscle force quickly. During ageing, it is lost more rapidly than muscle strength, contributing to disability, falls, reduced quality of life and, in some instances, death,” Warden explained.He said “the current study provides proof-of-concept evidence to proceed to the larger studies that are required to demonstrate whether myostatin antibody treatment improves quality of life and reduces falls and their consequences during ageing”.  “This is an important and exciting first step,” Warden noted in an official statement.last_img read more

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Up above the world so high

first_imgIIC is going to present an exhibition of photographs of the night skies across India, by Cyril Lucido Kuhn in the first week of July in the national Capital. The images have been captured over a span of two years in several destinations across the country. The exhibition is the first milestone on a journey which began in the Nilgiris when the photographer witnessed the Milky Way for the first time.During his journey, Cyril became aware of the rapid and ever increasing loss of our night sky. We are unable to see the stars in the night sky due to light pollution. A perfect night sky is hidden from our view because of the illumination of the atmosphere from the urban lights.The aim of the artiste is to share the extraordinary beauty of the sky bursting with stars, planets and other celestial objects. He also wishes to highlight the negative impacts, glare from the artificial lights has, on the environment disturbing all life forms and blocking our vision to the universe.last_img read more

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Presidency Univ signs MoU with CNCI on modern DNA sequencing technology

first_imgKolkata: Presidency University has signed a Memorandum of Understanding (MoU) with Chittaranjan National Cancer Institute (CNCI) for collaborating on a modern sequencing technology that will help researchers sequence DNA faster for investigating cervical cancer. Sequencing has been in practice for a long time, but Next Generation Sequencing (NGS) is a new concept, Presidency University professor and programme coordinator Abhik Saha said. Presidency University Vice-Chancellor Anuradha Lohia said on Monday that the MoU inked recently with the CNCI, one of the oldest cancer research institutions in the country, would give an opportunity to students for undergoing training. It will also open a new chapter in medical research, she said. “With this research, we will be able to see if any other microbe can cause cervical cancer, apart from the virus. “We also aim to develop a diagnostic kit, with which we can test samples from patients,” the programme coordinator said. Depending on the outcome, such research would be used to investigate other forms of cancer, other than cervical cancer, Saha said. Another university official said it will help students have access to different laboratories involved in such research and help both the institutions. CNCI authorities did not comment on the issue.last_img read more

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Two days after being kidnapped girl returns home

first_imgNEW Delhi : A four-year-old girl who was kidnapped from Hari Nagar on Friday returned home on her own after two days, police said on Monday.Cops have lodged a case of kidnapping and are looking for the accused. According to police, the medical examination of the girl has ruled out sexual assault. Cops said the girl was abducted by a man on Friday, when she had gone to take prasad at a religious gathering on the occasion of Guru Purab. A tall man was captured in the CCTV camera, carrying a helmet on his shoulder and following the girl. Also Read – Rain batters Kolkata, cripples normal lifeLater, the girl disappeared and the parents lodged a complaint at Hari Nagar Police station. “The problem in the investigation is the child is too small to narrate the kidnapping story or tell the police who took her along with him. “That is the reason police is relying on human as well as technical assistance to solve the case,” said Additional Deputy Commissioner of Police (West) Sameer Sharma. Copss are still puzzled about the motive of kidnapping and said that once they succeed in arresting the accused, the motive would be clear and sections would be modified in the FIR accordingly.last_img read more

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Combat sweat with natural fabrics

first_imgIt’s best to wear natural fabrics to beat the heat and to keep skin problems at bay, say experts.Follow these simple tips and deal with sweat: Loose clothes don’t touch your body and allow your body to breathe. Believe it or not, but loose fitting apparel like peplum tops, flowy tops or loose pants will always keep you cooler than a pair of skin tight tank and fit denims.Keep yourself cool by switching to breathable and sweat absorbing fabrics. Always dress up in clothes with natural fabrics it will keep your temperature low. Also Read – Add new books to your shelfAvoid wearing dresses with embellishments as they weigh down your clothes and leads the fabric to touch your skin, trapping the body heat. Embellishments also don’t let air pass through the fabric, thus causing sweating.Wearing a light coloured and relaxed fit T-shirt can save you from sweating. They can be played around in different styles.Summer style is incomplete without chinos and denim shorts. When it comes to shorts, fit and length is the key. You can pair up denim shorts with cotton Polo T-shirt to get the comfort and style.last_img read more

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