Month: August 2019

Quantum communication through synergy

first_img The best of both worlds: How to solve real problems on modern quantum computers 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: Quantum communication through synergy (2009, January 19) retrieved 18 August 2019 from https://phys.org/news/2009-01-quantum-synergy.html Conventional wisdom, when applied to quantum communication, seems to say that one must have a private channel in order to communicate privately. Nonprivate channels, the thinking goes, should not be able to send quantum information. It is this very thinking that Smith, along with colleague John Smolin, at the IBM T.J. Watson Research Center in Yorktown Heights, New York, could be overturning. In theory, and with the help of some mathematical equations, Smith and Smolin show that it might be possible to combine nonprivate channels to create a channel that would transmit quantum information – and communicate privately at greater distances than currently possible. Their reasoning can be found in Physical Review Letters: “Can Nonprivate Channels Transmit Quantum Information?”“If you had a channel that didn’t allow you to communicate privately,” Smith points out, “you would think you have a weak resource. But when you start looking at these channels, and you start looking at their limits, you begin to see something else.” This “something else,” Smith continues, includes qualities that allow nonprivate channels to combine in a way that allows them to possibly become useful for quantum communication.“There are these features that allow the some of the nonprivate channels to interact with each other in a synergestic way to become useful. Interestingly, this is not something that happens classically. But it could happen with quantum information channels.”Smith says that even though individually these channels might look weak, when they are put together, it is possible that they would have the ability to carry more quantum information than the sum of their individual capacities combined. “In our paper, we are presenting ideas of how to design protocols that allow higher rates of quantum communication, over longer distances, than what we can currently do right now.”Even though this method of quantum communication looks promising, Smith admits that not all of the components are properly understood. Like so much in quantum mechanics, it appears that something could or does happen, but the why isn’t always easy to grasp. “Right now,” he says, “we’re trying to better understand the individual resources, and some of their bounds. We are trying to develop a way to quantify what the resources actually are. We’re starting to develop a feel for what different classes of channels might be made of, but we don’t have good characterization yet.”Part of understanding characterization, and quantifying the components of quantum communication, Smith continues, is the idea of figuring out the why behind this phenomenon. “We have information that shows that some of these nonprivate channels are useless for quantum communication, but when you combine them, they are quite useful. Why is this?”“There is something strange going on here. But if we can get to the bottom of it, we should be able to improve upon our ability with quantum communication dramatically.”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.center_img Explore further (PhysOrg.com) — When most people think of quantum communication, they think in terms of private communication channels – the ability to send messages without a third-party deciphering them. Indeed, quantum cryptography represents a method of sending information that cannot be eavesdropped upon. Without the proper key for decoding the intercepted message, all an interloper would receive is gibberish. To make quantum cryptography work, Graeme Smith tells PhysOrg.com, “We try to understand the protocols and use specially designed channels to send messages and also to shed light on the general theory of privacy in quantum mechanics.”last_img read more


August 31, 2019 0

Robotic boats to travel across Pacific Ocean

first_img © 2011 PhysOrg.com The self-propelled Wave Gliders use wave energy for propulsion. Image credit: Liquid Robotics On the above-water part of the Wave Glider, solar cells recharge a battery that powers data sensors and transmitters. Underwater fins use wave energy for propulsion. Image credit: Liquid Robotics The Wave Gliders are the flagship product of Liquid Robotics, which is headquartered in Sunnyvale, California. The Pacific voyages will not only demonstrate that such a task is feasible for robotic ocean vehicles, but will also be used to collect lots of data on features such as water salinity, temperature, oxygen content, conductivity, depth, crude oil fluorescence, wave features, wind features, and the weather. The Wave Gliders will use only wave energy for propulsion with the help of underwater fins, so no refueling is required. Solar cells on the tops of the vehicles will recharge the battery that powers the data sensors and transmitters.All this data will be transmitted in real-time via satellites and made freely available to anyone who registers with Liquid Robotics. Liquid Robotics and Ocean in Google Earth are providing a platform for registered users to follow the expedition virtually. To encourage scientists to use this data, the company is hosting the “PacX Challenge.” By submitting a one-page abstract outlining their scientific intentions with the data, researchers have the chance to win six months’ free use of a Wave Glider to collect whatever data they want. Explore further East Coast gliders yield valuable marine life data The Wave Gliders are named after famous oceanographers and navigators: Piccard Maru (after Jacques Piccard, who explored the Mariana Trench) and Fontaine Maru (after Matthew Fontaine Maury, who wrote the first extensive book on oceanography) are bound for Japan. Benjamin (after Benjamin Franklin, who helped chart the Gulf Stream) and Papa Mau (after Pius “Mau” Piailug, a Micronesian navigator who helped test lost Hawaiian navigational techniques) are bound for Australia.Liquid Robotics also sells the Wave Gliders to customers including energy companies, who use them to monitor offshore rigs, and government organizations. The Wave Gliders cost about $200,000 each. Liquid Robotics predicts future applications could include monitoring currents in shipping lanes, guarding wild fisheries, running offshore fish farms, and understanding of the role of the oceans in the earth’s carbon cycle.“These Wave Gliders are much like small ‘spacecraft’ that open up new opportunities for robotic exploration,” said Ed Lu, chief of innovative applications at Liquid Robotics, in a press release. “I challenge all scientists who are interested in advancing ocean exploration to take advantage of this unique opportunity. What scientific questions can we address with this new and unique data set?” (PhysOrg.com) — Last Thursday, November 17, four unmanned Wave Gliders left the coast of San Francisco and began a 300-day journey across the Pacific Ocean. The vehicles, which are self-propelled and remotely piloted, will travel together to Hawaii and then two will head to Japan and the other two to Australia. The trips will cover about 37,000 miles (60,000 km), setting a Guinness World Record for the longest distance ever traveled by an unmanned ocean vehicle. More information: http://www.liquidr.com/pacxvia: IEEE Spectrum Citation: Robotic boats to travel across Pacific Ocean (2011, November 21) retrieved 18 August 2019 from https://phys.org/news/2011-11-robotic-boats-pacific-ocean.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


August 31, 2019 0

Researchers discover daddy longlegs spiders capture prey using glue

first_img More information: Gluing the ‘unwettable’: soil-dwelling harvestmen use viscoelastic fluids for capturing springtails, J Exp Biol 217, 3535-3544. DOI: 10.1242/jeb.108852 AbstractGluing can be a highly efficient mechanism of prey capture, as it should require less complex sensory–muscular feedback. Whereas it is well known in insects, this mechanism is much less studied in arachnids, except spiders. Soil-dwelling harvestmen (Opiliones, Nemastomatidae) bear drumstick-like glandular hairs (clavate setae) at their pedipalps, which were previously hypothesized to be sticky and used in prey capture. However, clear evidence for this was lacking to date. Using high-speed videography, we found that the harvestman Mitostoma chrysomelas was able to capture fast-moving springtails (Collembola) just by a slight touch of the pedipalp. Adhesion of single clavate setae increased proportionally with pull-off velocity, from 1 μN at 1 μm s−1 up to 7 μN at 1 mm s−1, which corresponds to the typical weight of springtails. Stretched glue droplets exhibited characteristics of a viscoelastic fluid forming beads-on-a-string morphology over time, similar to spider capture threads and the sticky tentacles of carnivorous plants. These analogies indicate that viscoelasticity is a highly efficient mechanism for prey capture, as it holds stronger the faster the struggling prey moves. Cryo-scanning electron microscopy of snap-frozen harvestmen with glued springtails revealed that the gluey secretions have a high affinity to wet the microstructured cuticle of collembolans, which was previously reported to be barely wettable for both polar and non-polar liquids. Glue droplets can be contaminated with the detached scaly setae of collembolans, which may represent a counter-adaptation against entrapment by the glue, similar to the scaly surfaces of Lepidoptera and Trichoptera (Insecta) facilitating escape from spider webs. Mitostoma chrysomelas. Credit: Wikipedia/CC BY 3.0 Journal information: Journal of Experimental Biology © 2014 Phys.org Citation: Researchers discover daddy longlegs spiders capture prey using glue (2014, October 3) retrieved 18 August 2019 from https://phys.org/news/2014-10-daddy-longlegs-spiders-capture-prey.html Credit: Jonas O. Wolff, Functional Morphology and Biomechanics, University of Kiel Explore further We all know about daddy longlegs (known more scientifically as harvestmen), they’re spiders with tiny bodies and really long legs, and even though we know they can’t hurt us, many are still a little bit afraid of them. At any rate, for many years, biologists have wondered about the bobs on the ends of some of their pedipalps (forelegs). They appeared to be moist, even glue-like—but it wasn’t clear what the liquid was for—to help with climbing? To help with catching food? No one knew, until now.To find out, the researchers captured several specimens and brought them into their lab, along with some of their favorite prey, tiny arthropods called springtails (because they have a biomechanical spring on their underside that helps them leap away from predators). The team used high-speed cameras to film what happened when the spider tried to catch the springtail, then reviewed the results. They found that when it came time to grab the springtail, the spider squirted a tiny bit of “glue” onto it, preventing it from escaping.But that wasn’t the end of the study, the team also cut off some of the spider’s pedipalps to get a closer look at the fluid—they found the adhesive strength of the glue was sufficient to hold an entire springtail when suspended. Taking an even closer look, the researches froze (using liquid nitrogen) one spider that had glued a springtail and placed them both under a cryo-scanning microscope to see how it was that the glue worked so well. They found that the glue completely wetted the cuticle on the springtail, which overcame liquid repelling microstructures and removable scales allowing for a very good grip—strong enough to hold on even as the springtail tried using its spring to zip away. App helps homeowners identify spiders A team of researchers in Germany has finally figured out what the gooey-covered hairs on a daddy longlegs’ pedipalps are for—they hold a type of glue that is used to prevent prey from escaping. The team describes how they made this discovery in their paper published in The Journal of Experimental Biology—by filming the spiders with high-speed cameras, testing the fluid and looking at them under a scanning microscope. 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


August 31, 2019 0

Comet Lovejoy shows asymmetric behavior at perihelion

first_img Explore further Citation: Comet Lovejoy shows asymmetric behavior at perihelion (2016, July 26) retrieved 18 August 2019 from https://phys.org/news/2016-07-comet-lovejoy-asymmetric-behavior-perihelion.html © 2016 Phys.org 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. (Phys.org)—Indian astronomers have recently conducted spectrographic observations of long-period Comet Lovejoy to study its gas emission. They found that this comet showcases an asymmetric behavior at perihelion and an increase in the activity during the post-perihelion phase. The findings were detailed in a paper published July 22 on the arXiv pre-print server. Photograph of the comet C/2014 Q2 (Lovejoy) taken on Jan. 19, 2015, from Tucson, Arizona, using a Sky-Watcher 100mm APO telescope and SBIG STL-11000M camera. Credit: John Vermette More information: Optical Spectroscopy of Comet C/2014 Q2 (Lovejoy) from MIRO, arXiv:1607.06682 [astro-ph.EP] arxiv.org/abs/1607.06682AbstractSpectra of comet C/2014 Q2 (Lovejoy) were taken with a low resolution spectrograph mounted on the 0.5 m telescope at the Mount Abu Infrared Observatory (MIRO), India during January to May 2015 covering the perihelion and post-perihelion periods. The spectra showed strong molecular emission bands (C2, C3 and CN) in January, close to perihelion. We have obtained the scale lengths for these molecules by fitting the Haser model to the observed column densities. The variation of gas production rates and production rate ratios with heliocentric distance were studied. The extent of the dust continuum using the Af-rho parameter and its variation with the heliocentric distance were also investigated. The comet is seen to become more active in the post-perihelion phase, thereby showing an asymmetric behaviour about the perihelion. Comet Lovejoy, formally designated C/2014 Q2, is an Oort cloud comet, discovered by Terry Lovejoy in August 2014. Its perihelion was on January 30, 2015 at a heliocentric distance of 1.29 AU, offering astronomers an excellent opportunity to observe its activity—in particular, the emission of numerous organic molecules in gas.The scientists, led by Kumar Venkataramani of the Physical Research Laboratory in Ahmedabad, India, utilized the LISA spectrograph to obtain spectra of the comet. LISA is a low-resolution, high luminosity spectrograph, designed for the spectroscopic study of faint and extended objects. The instrument is installed on the 0.5 m telescope at the Mount Abu Infra-Red Observatory (MIRO), Mount Abu, India.The observation campaign lasted from January to May 2015. It covered the period during which the comet’s heliocentric distance varied from 1.29 AU, just prior to perihelion, to around 2.05 AU post perihelion. The spectra obtained by the researchers show strong molecular emission bands of diatomic carbon, tricarbon, cyanide, amidogen, hydridocarbon and neutral oxygen.”Various molecular emission lines like C2, C3, CN, NH2, CH, O were clearly seen in the comet spectrum throughout this range. The most prominent of them being the C2 molecule, which was quite dominant throughout the time that we have followed the comet. Apart from the C2 emission band, those of CN and C3 were also quite prominent,” the scientist wrote in the paper.When a cold icy body like the Comet Lovejoy passes by the sun near perihelion, its ices start sublimating, releasing a mixture of gas and dust, which form the coma. Studying these emissions is crucial for scientists as comets could hold the key to our understanding of the solar system’s evolution and the origin of life in the universe. Therefore, the abundance of volatile material in comets is the target of many scientific studies that seek to reveal the secrets of planet formation and demonstrate the conditions that occurred when our solar system was born.According to the study, the gas production rate increased after perihelion and exhibited a decreasing trend only after February 2015. The researchers also noted a simultaneous increase in gas and dust, indicating an increase in the overall activity of the comet after its perihelion passage.”This kind of asymmetry has been seen in many comets. (…) Although we do not have data points at exactly the same distance for pre- and post-perihelion passages, we can, perhaps, say that this comet may have a large positive asymmetry,” the paper reads.The scientists concluded that this asymmetry suggests that there might be volatile material present beneath the surface of the comet. It is also possible that the surface of the comet’s nucleus consists of layers of ice that have different vaporization rates.However, as the team noted, more exhaustive study is required to confirm their conclusions. Scientists investigate change in activity of comet 17P/Holmeslast_img read more


August 31, 2019 0

Galileos freefalling objects experiment passes space test further proving equivalence principle

first_imgA team of researchers from the French Aerospace Lab and at the Côte d’Azur Observatory working on France’s MICROSCOPE satellite project has further confirmed the equivalence principle by recreating Galileo’s free-falling objects experiment in a satellite. In their paper published in the journal Physical Review Letters, the group describes their experiment and why it was carried out. Credit: CNES/D. Ducros Citation: Galileo’s free-falling objects experiment passes space test further proving equivalence principle (2017, December 5) retrieved 18 August 2019 from https://phys.org/news/2017-12-galileo-free-falling-space-equivalence-principle.html Satellite to test universality of freefall © 2017 Phys.org More information: Pierre Touboul et al. MICROSCOPE Mission: First Results of a Space Test of the Equivalence Principle, Physical Review Letters (2017). DOI: 10.1103/PhysRevLett.119.231101ABSTRACTAccording to the weak equivalence principle, all bodies should fall at the same rate in a gravitational field. The MICROSCOPE satellite, launched in April 2016, aims to test its validity at the 10−15 precision level, by measuring the force required to maintain two test masses (of titanium and platinum alloys) exactly in the same orbit. A nonvanishing result would correspond to a violation of the equivalence principle, or to the discovery of a new long-range force. Analysis of the first data gives δ(Ti,Pt)=[−1±9(stat)±9(syst)]×10−15 (1σ statistical uncertainty) for the titanium-platinum Eötvös parameter characterizing the relative difference in their free-fall accelerations.center_img Explore further Journal information: Physical Review Letters Approximately 450 years ago, Galileo, as some have reported, dropped cannonballs of different sizes from the Leaning Tower of Pisa to prove that they would hit the ground at the same time. 350 years later, Einstein published his Theory Of General Relativity, which included the equivalence principle, and as Galileo demonstrated, stated that objects with different masses fall at the same rate due to gravity. In this new effort, the researchers have performed roughly the same experiment as Galileo, except they have done it in space and measured the results with far more precision.Scientists continue to test the equivalence principle because they believe that if they can find a violation, it could reconcile the impasse regarding quantum theory and general relativity.The experimental equipment aboard the MICROSCOPE satellite consisted of one cylindrical shell set inside of another larger cylindrical shell. The cylinders were small, of course, just a few centimeters long, and were made of different materials—the inner one of platinum and rhodium, the outer from much less dense titanium and aluminum. Running the experiment in space removes factors that can disrupt gravitational force, such as water moving underground. The cylinders free fall as they move through space with an electric field present to keep them from veering from a straight downward path. Their fall is measured very precisely. Any deviations in acceleration would be seen as a change in the electrical field. The team reports that none were found. The researchers report their experiment offered 10 times the precision of previous experiments meant to do the same thing. They note that they believe it will be possible in the future to conduct the same experiment with even more precision by better controlling the temperature inside the satellite. 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


August 31, 2019 0

Taking to the roads

first_imgThe works at the exhibition Ways of the Road was created during three week artist residency held in the village of Partapur in Rajasthan. The residency, Sandarbh, was a curated one; the focus was on the bus that runs through the village and  the route it follows. Even more than the bus, the artist found himself preoccupied with documenting the roadPhotography has a long history of interactions with the road, the challenge was to make this project different. Fabien Charuau decided to follow the road and stop every kilometer to document what he saw. At every kilometre mark, he would shoot three images on three different film cameras – one of the roads, another of a person he met there and one of a landmark. Also Read – ‘Playing Jojo was emotionally exhausting’The experiments during his previous work led him to use different processes and visual technologies from the field that he wants to document. As for the equipment, artist has used three cheap film cameras and some film that he bought from the village.He  used a scanner ,again locally sourced, treating it as a dark room to produce contact sheets. The resulting contact sheet is a very long print, the map of the road he has travelled, each frame being a milestone of the road. Also Read – Leslie doing new comedy special with NetflixThe crux of the project is what the road means to photography and many linear movements in photography.Whatever he has done has to do with linearity; the way the film moves in the camera, me moving ahead on the road, the scanning of the contact sheet, the contact sheet being printed, the experience of looking at the final print on the floor, even the negative could be viewed as a road.Charuau is a Bombay based visual artist working thus far with photography and video.Having spent half his life in india where his journey with photography began, he sees himself as an Indian photographer of French origin.Besides having had his work shown in solo and group shows and at photo festivals, his reflection on Indian photography has also seen him take on a curatorial role for a group show on contemporary Indian photography in Paris two years ago. He also writes on Indian photography for the French magazine Photo and for Tasveer journal.last_img read more


August 31, 2019 0

Thespians come together

first_imgThe recent Earthquake in Nepal is still alive in our minds in which thousands of people died and the country’s homes and other infrastructure have been devastated. With a view to extend support to the victims, National School of Drama with the support of performing arts fraternity is organising an event Nepal Sadhbhawna Natya Aayojan that starts from May 16 – 24 at the NSD campus.  Also Read – ‘Playing Jojo was emotionally exhausting’“It is the duty of performing artistes to come together and stand up for the victims,” NSD director Waman Kendre said at a press conference held in the Capital.“It was very important for the artistic community to come together and contribute. I am glad that at such a short notice, we have been able to bring many stakeholders on board,” Kendre said.He further added, “Within 24 hours, we decided to organise the event and chose ongoing productions around Delhi or productions that are going to be staged soon. We didn’t have much time, so thought of selecting crowd-puller productions.”  Also Read – Leslie doing new comedy special with NetflixThis aayojan will showcase 12 plays of eminent theatre directors. To name these theatre directors are Raj Bisaria, Neelam Mansingh Choudhary, Rajinder Nath, Bansi Kaul, M K Raina, Tripurari Sharma, Prof. Waman Kendre, Chitra Singh, Shobha Deepak Singh, Baharul Islam, Prof. Suresh Bhardwaj and Ramji Bali.  The plays to be staged are – Gazab Teri Adaa, Shree Durga, Bagiya Bancha Ram Ki, Qisse Soojh Boojh Ke, Azad Maulana, Azad Maulana, Koi Baat Chale, Kabira Khada Bazaar Mein, Qissa Maujpur Ka, Ghasiram Kotwal. As the intention is to provide aid to quake victims, the ticket prices too are a bit on higher side, considering the fact that NSD is known for offering best productions at pocket-friendly prices.last_img read more


August 31, 2019 0