‘Connecting the dots’ for quantum networks Explore further Recently, some approaches have suggested “rediscovering” old techniques such as analog computing, which usually lie outside the usual qubit architecture, in the hope of finding new pathways to experimentally realize quantum computation. For instance, using analog techniques and the quantum properties of atomic clusters called Bose-Einstein condensates, a team of researchers from Japan has recently improved upon a classical factoring algorithm.“Any algorithm where the output is continuous rather than divided into bits (as on a digital computer) is analog,” Mark Sadgrove of the Japan Science and Technology Agency (JSTA) told PhysOrg.com. “In our case, we measure quantities which are continuous in principle. By this I mean that the energy or the probability to find an atom with a given momentum are continuous variables, in theory. In practice, we use a finite number of atoms, so in some sense the final outputs are discrete, but theoretically the result of the computation is analog in nature.”Sadgrove and his colleagues Sanjay Kumar of the University of Electro Communications (UEC) in Chofushi, Chofugaoka, and Ken’ichi Nakagawa, who has affiliations with both JSTA and UEC, have demonstrated that, compared with the classical implementation, their method can distinguish more accurately between factors and non-factors of large numbers. Specifically, their quantum system could increase the accuracy of a classical algorithm called the Gauss sum algorithm, a technique pioneered by Wolfgang Shleich of Ulm University in Germany.Their quantum system consists of thousands of rubidium-87 atoms that are cooled to near absolute zero to form a Bose-Einstein condensate (BEC). At such a low temperature, the atoms’ wavelengths increase and overlap, so that the cluster becomes a single quantum state and obeys quantum laws, yet has a relatively large size. The physicists zapped the BEC with a brief light pulse composed of two counter-propagating beams. They programmed one beam to have phase jumps (to displace the beam’s wavelength), while the second beam had no phase jumps. Programming the first beam served as the input method, representing an integer to be factored. (PhysOrg.com) — Theoretically, quantum computing has the potential to work more efficiently and accurately than classical computing for certain processes, such as factoring. But quantum methods are experimentally challenging, since they often require tiny, fragile systems that are difficult to handle. An absorption image of the expanding Bose-Einstein condensate, demonstrating the diffraction pattern which constitutes the factoring signal. Image credit: Mark Sadgrove, et al. 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. The dynamics of the atoms subject to the pulse could then be used to perform factoring calculations. After applying the pulse, the researchers allowed the BEC to expand freely for 14 ms. They then took an absorption image of the BEC, which showed that the pulse had separated the atoms in the BEC into different momentum orders. The atoms formed a diffraction pattern, based on the relative number of atoms in each momentum order, which the physicists could interpret as the “factoring signal.” Specifically, high-momentum atoms represented factors, and low-momentum atoms represented non-factors.“You can think of the laser beam as containing the software (encoded by phase jumps) and the atoms as providing the hardware (their natural dynamics in response to the light field is what actually calculates the Gauss sum),” Sadgrove explained.In contrast to the usual Gauss sum, which is fundamentally limited in its accuracy, the quantum method significantly outperformed the classical method, in some cases doubling the atomic visibility and offering near-perfect factoring. “In our case, our current method is still slow – it doesn’t make factoring easy,” Sadgrove said. “What we showed is that quantum mechanics offers an unexpected improvement to the Gauss sum method, overcoming a fundamental accuracy limit. If the atoms behaved classically, there would be no enhancement.”The researchers noted that the higher accuracy comes at a cost of requiring more atoms, so the quantum method’s efficiency is about the same as that of the classical method. Nonetheless, as Sadgrove explained, the method offers a novel experiment in a field in which experiments are difficult to realize.“You might know that everyone doing research in quantum information is excited about [Peter] Shor’s algorithm for quantum factoring,” Sadgrove said. “Shor found a remarkable way to factor numbers using the quantum properties of interference and entanglement, which offers amazing savings in the time it takes for factoring a number. But Shor’s algorithm is hard to implement. It’s only been done successfully for up to the number 15 at the moment, and some people don’t even consider that to be a real test due to some details about the way the algorithm works. So that’s the current state of play regarding quantum factoring.”He added that researchers continue to investigate Shor’s algorithm because of its potential impact on security: “In terms of applications, there’s just one, but it’s very important. If you could do real quantum factoring, then the RSA encryption used to do secure transactions in public situations would be no good anymore. That’s because it relies on the fact that factoring large numbers is a hard problem. But quantum factoring makes it easy.”In the future, the physicists hope to use entangled systems as a factoring method, which they say the present scheme is ideally suited for. They also plan to investigate the use of multiple, correlated atomic ensembles to perform factoring of different integers simultaneously. “We would also like to extend the method beyond factoring,” Sadgrove said. “We can actually compute general ‘exponential sums’ with this method. A Gauss sum is a simple example of an exponential sum, as is a Fourier transform, which can be used to extract information about a signal. These so called ‘exponential sums’ are intricately tied to the most interesting parts of number theory, such as the distribution of prime numbers, which is still unknown. We think there may be other powerful applications of exponential sums apart from factoring.”More information: Sadgrove, Mark; Kumar, Sanjay; and Nakagawa, Ken’ichi. “Enhanced Factoring with a Bose-Einstein Condensate.” Physical Review Letters, 101, 180502 (2008).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. Citation: Physicists use Bose-Einstein condensates to enhance factoring algorithm (2008, November 10) retrieved 18 August 2019 from https://phys.org/news/2008-11-physicists-bose-einstein-condensates-factoring-algorithm.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. Artificial trees. Image: Institution of Mechanical Engineers The engineers from Britain’s Institution of Mechanical Engineers (IME) have asked their government for an investment of 10 million pounds (around 16.3 million dollars) in these ideas to counter the threat to Britain posed by global warming. One of the authors of the report, Dr Tim Fox, said geo-engineering techniques could buy us a few extra years’ breathing space while we transition to a low-carbon world, and may help ward off the climate change scenarios we fear. The report claimed global temperatures could rise by as much as 6°C in the next 90 years if we don’t act soon, and the results would include major refugee movements as well as food and water shortages. Algae-coated buildings. Image: Institution of Mechanical Engineers One proposal was the building of forests of artificial trees. Each synthetic tree could capture up to 10 tons of CO2 a day, which is thousands of times more than a real tree. Each tree would cost around $24,400, and a forest of 100,000 of them could be constructed within the next couple of decades using existing technologies. A forest that size would be able to remove 60% of the UK’s total CO2 emissions. Globally, forests of five to ten million trees could absorb all the CO2 from sources other than power plants.The trees would have a special synthetic filter that absorbs carbon dioxide. When the filters had absorbed their load of CO2 they would be replaced with new filters and the old ones would be stored in empty gas and oil reservoirs, such as depleted oil wells in the North Sea. The trees are already at the prototype stage and their design is well-advanced. The prototype is the size of an average shipping container.Another proposal put forward by the study was to install transparent tubes filled with algae on the outside of buildings. The “algae based photobioreactors”, as they call them, would absorb carbon dioxide from the atmosphere, and could later be turned into charcoal, which could then be buried to trap the carbon dioxide. Reflective buildings. Image: Institution of Mechanical Engineers (PhysOrg.com) — A new study on how technology could help to regulate climate change has studied hundreds of ideas, and selected three considered practical and able to be implemented quickly. The report’s authors propose the construction of forests of artificial trees and installing tubes of algae on the sides of buildings to absorb carbon dioxide. They also proposed painting the roofs of buildings white to keep the Earth cool by reducing the amount of solar radiation absorbed. Explore further Citation: Forests of Artificial Trees Could Slow Global Warming (2009, August 28) retrieved 18 August 2019 from https://phys.org/news/2009-08-forests-artificial-trees-global.html The third idea proposed by the IME was to paint city roofs white to reflect sunlight back into space and prevent it warming the Earth. Cities can be up to 4°C hotter than suburban areas, and reflective roofs could reduce the need for cooling and save up to 60% of a building’s energy use.Dr Fox warned that geo-engineering ideas such as those proposed are not a silver bullet that will solve all the problems, and they would need to be used in conjunction with other measures such as reducing our emissions and adapting to changes in the climate.More information: Read the full Institution of Mechanical Engineers report© 2009 PhysOrg.com Plant a tree and save the Earth?
A Pallas’s long-tongued bat, representing one of six species used in the new study. Bat researchers from the biology departments of the University of Western Ontario and the University of Regina (Saskatchewan, Ca) theorized that the amount of ethanol in the fermented fruit and nectars that the bats ingested was likely to induce intoxication.The researchers gave “sobriety tests” to 106 bats, representing six species of New World Leaf-nosed bats, after the bats had consumed enough ethanol to bring their blood alcohol content (BAC) up to 0.3 or higher. (The legal limit of BAC for human drivers is .08!) The bat BAC levels were attained by feeding the test bats ethanol mixed with sugar water. Their control group counterparts received just the plain sugar water.The bats took flight in a researcher-constructed obstacle course in which the bats would have to navigate according to five standard identifiable flying behaviors of phyllostomide bats. Otherwise, they would betray their drunkenness. Additionally, the biologists expected the alcohol to alter the bats’ echolation, or calling behavior, so they recorded the bats with ultrasonic condenser microphones.”We went into the study fully expecting that some of the species wouldn’t be able to hold their drink,” study co-author Brock Fenton, from the University of Western Ontario, told National Geographic News.But once the bats went through the test – some, mind you, with three times higher BAC than a drunk driver – the researchers found no measurable change in either flight or calling behaviors. A prior study conducted with Old World bats dieting on seasonal fruit and nectar reported signs that bat motor skills and echolation were clearly affected by the ethanol content in their diets. Apparently, the New World bats, exposed to high-ethanol products all year round, have developed an alcohol tolerance that has “afforded them an evolutionary edge.” Fenton and his colleagues are now trying “to find a company that sells alcoholic refreshments who will sponsor an expanded study.” (PhysOrg.com) — New World Leaf-nosed bats (Chiroptera Phyllostomidae) are thriving in the tropical forests of Central and South America, even though their diets consist of more fruits and nectars than their counterparts in the Old World. Strange thing is the phyllostomide bats are drawn to fruits and nectars even after they have fermented. More information: Drinking and Flying: Does Alcohol Consumption Affect the Flight and Echolocation Performance of Phyllostomid Bats? Citation: Orbach DN, Veselka N, Dzal Y, Lazure L, Fenton MB (2010) Drinking and Flying: Does Alcohol Consumption Affect the Flight and Echolocation Performance of Phyllostomid Bats? PLoS ONE 5(2): e8993. doi:10.1371/journal.pone.0008993 Study looks at metal baseball bat safety © 2010 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. Explore further Citation: Drunk Bats Manage To Pass Sobriety Tests (2010, February 18) retrieved 18 August 2019 from https://phys.org/news/2010-02-drunk-sobriety.html
Explore further More information: via Forbes Daniel G. Nocera. Credit: Courtesy of Daniel G. Nocera (Phys.org)—Harvard Chemist Daniel Nocera has announced during a lecture at the Energy Policy Institute in Chicago, that he and his colleagues have engineered a bacterium that has made it capable of taking in carbon dioxide and hydrogen, and excreting several types of alcohol fuels, along with biomass that can be burned and used as an energy source. During the talk, he claimed that a paper he and his colleagues have written regarding the work will soon be published in the journal Science. Bionic leaf: Researchers use bacteria to convert solar energy into liquid fuel Citation: Engineered bacterium inhales carbon dioxide and hydrogen and excretes fuel alcohols (2016, May 31) retrieved 18 August 2019 from https://phys.org/news/2016-05-bacterium-inhales-carbon-dioxide-hydrogen.html © 2016 Phys.org Nocera achieved a level of notoriety five years ago, when he and his team announced that they had created an artificial leaf that could be used to generate hydrogen for use as a fuel—that idea did not lead to hydrogen fuel cells displacing gasoline in automobiles, as he had hoped, so this go round, he has set his sights or providing a fuel source for those more in need—parts of India where there is still no electricity.The new bacterium, which has been named Ralston eutropha was first caused (via genetic engineering) to take in carbon dioxide and hydrogen, which it used to produce adenosine triphosphate, as is done with plants. The team then took the work further by applying techniques pioneered by Anthony Sinskey to cause the bacterium to then convert the ATP to various types of alcohols (isopentanol, isobutanol, isopropanol) which were then excreted. Nocera claimed that when the bacterium was allowed to reproduce, clusters of them were capable of producing alcohols at 6 percent efficiency and biomass at 10.6 percent efficiency, (plants in comparison are approximately 1 percent efficient at converting sunlight and carbon dioxide into biomass).Noting that some might see masses of such bacteria pulling carbon dioxide from the atmosphere as a possible solution to reducing global warming, which is believed to be at least partly caused by an excess of the gas in the atmosphere, Nocera suggested that was not the most likely outcome—he envisions people in need burning the alcohol and biomass as a fuel source, which would of course return the carbon dioxide back into the atmosphere—making it a carbon-neutral resource. He finished his lecture by announcing that he and his team are currently looking for investors to bring the technology to parts of India where it is so badly needed. Journal information: Science 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.
© 2016 Phys.org Citation: Two super-Earth-sized planets discovered orbiting a nearby star (2016, July 20) retrieved 18 August 2019 from https://phys.org/news/2016-07-super-earth-sized-planets-orbiting-nearby-star.html (Phys.org)—NASA’s Kepler spacecraft continues its fruitful exoplanet hunt with the newest discovery of two super-Earth-sized alien worlds. The newly detected planets are orbiting a nearby sun-sized star known as HD 3167, located some 150 light years away. The results are presented in a paper published July 18 on the arXiv pre-print server. Explore further K2 light curve of HD 3167. Top: the full K2 light curve. Both the numerous, shallow transits of HD 3167 b and three deeper transits of HD 3167 c are evident in the light curve by eye. Bottom left: K2 light curve (grey dots) phase folded on the transits of HD 3167 b, and best-fit transit model (thick purple line). Bottom right: K2 light curve (grey dots) phase folded on the transits of HD 3167 c, and best-fit transit model (thick purple line). Credit: Vanderburg et al., 2016. 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. New system discovered with five planets More information: Two Small Planets Transiting HD 3167, arXiv:1607.05248 [astro-ph.EP] arxiv.org/abs/1607.05248AbstractWe report the discovery of two super-Earth-sized planets transiting the bright (V = 8.94, K = 7.07) nearby late G-dwarf HD 3167, using data collected by the K2 mission. The inner planet, HD 3167 b, has a radius of 1.6 R_e and an ultra-short orbital period of only 0.96 days. The outer planet, HD 3167 c, has a radius of 2.9 R_e and orbits its host star every 29.85 days. At a distance of just 45.8 +/- 2.2 pc, HD 3167 is one of the closest and brightest stars hosting multiple transiting planets, making HD 3167 b and c well suited for follow-up observations. The star is chromospherically inactive and slowly rotating, ideal for radial velocity observations to measure the planets’ masses. The outer planet is large enough that it likely has a thick gaseous envelope which could be studied via transmission spectroscopy. Planets transiting bright, nearby stars like HD 3167 are valuable objects to study leading up to the launch of the James Webb Space Telescope. Although Kepler has lost two of its four reaction wheels and therefore cannot be precisely pointed toward stars, it is still capable of detecting new exoworlds. The spacecraft is now in its extended mission, known as K2, during which it has already found over 100 new planets. The HD 3167 system is just the latest addition to the vast collection of extrasolar worlds detected by K2.HD 3167 was observed by Kepler between January 3 and March 23, 2016 during Campaign 8 of its K2 mission. This observation campaign allowed a team of astronomers, led by Andrew Vanderburg of the Harvard–Smithsonian Center for Astrophysics (CfA), to detect two transit signals that could be planets circling around this nearby star.”We identified two planet candidates transiting HD 3167 after processing pixel-level data to produce a light curve, removing systematic effects due to Kepler’s unstable pointing, and searching for planets using a Box Least Squares periodogram search,” the researchers wrote in the paper.To confirm the planetary status of these candidates, the team conducted follow-up observations employing the Tillinghast Reflector Echelle Spectrograph (TRES) on the 1.5 m telescope at the Fred L. Whipple Observatory on Mt. Hopkins, Arizona and the Robo-AO adaptive optics system installed at the 2.1 m telescope at the Kitt Peak National Observatory, also in Arizona. They also used statistical techniques to validate the planetary nature of the transiting signals.The confirmed exoplanets received designation HD 3167 b and HD 3167 c. With a radius of about 1.6 Earth radii, HD 3167 b is the inner planet, orbiting the host star in just slightly less than one day. The outer planet is nearly three times bigger in size than Earth and has an orbital period of approximately 30 days.HD 3167 could be an excellent target for further follow-up observations as it is one of the closest and brightest stars hosting multiple transiting planets. The scientists noted that this system is highly suitable for precise radial velocity observations to measure the planets’ masses.”If HD 3167 b is rocky with a mass of about four Earth masses, it should induce radial velocity variations with a semiamplitude of about 3 ms−1. Depending on its composition, HD 3167 c could induce radial velocity variations with a semiamplitude of anywhere between 1 ms−1 and 3 ms−1. These signals should be readily detectable with modern spectrographs,” the paper reads.The team also emphasized that the outer planet is one of the best currently known small planets for atmospheric characterization with transit transmission spectroscopy. However, they also noted that the short period of HD 3167 b makes it likely that spectroscopic observations of HD 3167 c’s atmosphere might overlap with a transit of the inner planet.”This could be an efficient way to rule out a hydrogen-dominated atmosphere for HD 3167 b. Observers should be cautious, however, to ensure that a transit of HD 3167 b not interfere with out-of-transit observations necessary for calibration,” the researchers concluded.
The Shiromani Akali Dal on Tuesday said it will contest from four seats in the February 7 Delhi assembly polls, a day after its ally, the BJP, released its list of 62 candidates.“The Shiromani Akali Dal will fight from four seats in Delhi as per the formula of our alliance with the BJP,” Akali Dal Delhi unit president Manjeet Singh GK said.Manjinder Singh Sirsa will be contesting from Rajouri Garden, Harmeet Singh Kalka from Kalkaji and Jitender Singh Shunty from Shahdara. The party left out Shyam Sharma from the Hari Nagar seat and instead chose Avtar Singh Hit. All the three candidates – Sirsa, Kalka and Shunty – had fought the 2013 polls from the same constituencies and won. Sharma, however, had lost from Hari Nagar. Of the four candidates, Sirsa will contest on the Akali Dal’s weighing scale symbol, while the other three candidates will fight on the BJP symbol.
Kolkata: Six persons were killed after being struck by lightning in three separate incidents in the districts of Nadia, Bankura and Howrah. The incident took place on Wednesday morning when a thunder shower lashed various South Bengal districts. Lightning struck four persons including two brothers in Nadia leading to their deaths. While in separate incidents of lightning, two persons were killed in Bankura and Howrah each.According to Nadia police, the victims were all working in a field at Noamile in Nadia on Wednesday morning when the thundershowers started. The victims are Kalachand Seikh (60), Kamal Seikh (50), Najizul Seikh (30) and Azizul Seikh (25). Najizul and Azizul were two bothers. In another incident, a 58-year-old Kartin Soren was ploughing in Bankura’s Sarenga when he was struck by lightning. The third incident occurred in Howrah’s Panchla. The victim has been identified as Urmila Mondal (42) who was returning home from field work. Also Read – Heavy rain hits traffic, flightsThe district administrations took prompt action to restore normalcy following the incidents. There was heavy rainfall in some districts for hours causing water logging. Some of the roads became inundated. Nadia and Murshidabad witnessed a storm accompanied by moderate to heavy rainfall causing inconvenience to the commuters. It started raining from 11 am in some districts. The rain accompanied by storm, however, provided relief to the people in these districts as it brought down the temperatures by a few notches. Also Read – Speeding Jaguar crashes into Merc, 2 B’deshi bystanders killedThe sky remained overcast in North 24-Parganas, South 24-Parganas and also in the city in the morning hours. The city also received light rainfall on Wednesday morning.According to the weather office, a cyclonic circulation formed over the state that caused rains in the districts. There is also a possibility of thundershowers in the South Bengal districts during the evening in the next few days, the Met department predicted.It may be mentioned here that rain lashed some parts of North 24-Parganas, South 24-Parganas, Nadia, Hooghly and Kolkata on Wednesday evening. The Regional Meteorological Centre in Alipore predicted that it may rain in the city and adjoining areas, accompanied by storm in the next 24 hours. According to a weather expert, a strong moisture-laden wind which is blowing from the sea, turned the conditions favourable for a storm.
The People’s President was as much the Pupils’ President. So the eminent educationist Satyam Roychowdhury has named his latest literary venture as “Pupils’ President – APJ Abdul Kalam”. The 11th President of India, the ‘Missile Man’ behind India’s nuclear power, loved to be recognized as a teacher at the end of the day. Even at the age of 84, he used to travel a lot in and outside the country for delivering lectures at varied educational institutes. Also Read – ‘Playing Jojo was emotionally exhausting’In fact, he loved interacting with the students, inspiring them not only to