Can dark energy be explained by symmetrons

first_img Copyright 2013 All rights reserved. This material may not be published, broadcast, rewritten or redistributed in whole or part without the express written permission of “Since GR is very accurate in the laboratory and the solar system (regions in which the density is much higher than the cosmic mean), any fifth force must be ‘screened’ at high densities. The symmetron mechanism is one way to screen fifth forces.”In theory, a symmetron field will mediate a fifth force when its symmetry is broken, which requires a low-density vacuum. In this broken-symmetry phase, the symmetron couples to matter with a certain matter coupling energy. Here, Upadhye investigated the scenario where the matter coupling energy is 1 TeV and the symmetron mass is 10-3 eV. Then he solved the symmetron equations of motion to estimate constraints on the symmetron. Mathematicians offer unified theory of dark matter, dark energy, altering Einstein field equations This symmetron field regime, where the matter coupling energy is 1 TeV, is not only of interest due to its potential to be tested. This energy is also possibly associated with physics beyond the standard model. If this is true, experiments may reveal new effects that indicate new physics. One such experiment is the Eöt-Wash torsion pendulum experiment being carried out by scientists at the University of Washington in Seattle. Upadhye’s calculations allowed him to predict the torque signal that the symmetron would produce in an Eöt-Wash experiment.”It turns out that Eöt-Wash just happens to probe an interesting range of parameters because they have targeted the experiment at the right range of distances,” he said. “Fifth force screening mechanisms are not perfect, so there are residual fifth forces which can be detected by sufficiently sensitive experiments probing the right distances. My paper approximated these residual fifth forces and showed that Eöt-Wash excludes a substantial portion of them.”In this experiment, the presence of a fifth force would cause a metal disk to rotate in such a way as to align with a second metal disk.”Eöt-Wash uses a pair of metal disks with the same pattern of holes in each one,” Upadhye said. “The upper disk is suspended from a wire, allowing it to rotate freely, while the lower disk is rotated at a uniform rate. Fifth forces would cause the upper disk to rotate so as to align its pattern of holes with that on the lower disk. So, by looking for small torques on the upper disk leading to torsional oscillation, Eöt-Wash can search for fifth forces. The experiment can be repeated over a range of separations between upper and lower disks, allowing them to determine the rate at which fifth forces decrease with distance. Since this experiment has been designed to study distances as low as 50 microns, it is very useful for testing fifth forces due to dark energy.”Last December, Upadhye visited the Eöt-Wash group, and the researchers were very interested in testing new dark energy theories. Currently they are designing a new torsion pendulum experiment which should be substantially more sensitive to fifth forces. Upadhye plans to work further on his calculations to allow for more accurate testing.”An approximate treatment such as that in my symmetrons paper is useful for forecasting constraints, but in order to analyze the real data from the upcoming Eöt-Wash experiment, I plan to do more accurate computations of these fifth forces,” Upadhye said. “Several years ago I did such a computation for chameleon fifth forces. I plan to speed up that calculation as well as extend it to symmetron fifth forces. Using the extensive computational resources available here at Argonne, I will analyze Eöt-Wash data and test these dark energy theories.” The Eöt-Wash experiment may test for Upadhye’s predicted torque signal due to the symmetron field. A fifth force could be measured in the submillimeter distance between the two disks. (Left) An illustration of an older model and (right) a photo of a newer instrument. Credit: The Eöt-Wash Group at the University of Washington (—A field that permeates the universe and gives rise to a new force, or “fifth force,” between massive objects may be a candidate for dark energy and an explanation for why the expansion of the universe is accelerating. This field, called the symmetron field, is so named because it has a symmetry in regions of high density, while in regions of low density, such as a vacuum, the symmetry is broken and the field mediates the new force. More information: Amol Upadhye. “Symmetron Dark Energy in Laboratory Experiments.” PRL 110, 031301 (2013). DOI: 10.1103/PhysRevLett.110.031301center_img Citation: Can dark energy be explained by symmetrons? (2013, January 28) retrieved 18 August 2019 from Explore further Estimated constraints on symmetron dark energy, a new model in which fifth forces between massive objects play a role in accelerating the universe’s expansion. Credit: Upadhye. ©2012 American Physical Society Currently, the symmetron concept is purely theoretical. But in a new study, physicist Amol Upadhye at Argonne National Laboratory in Argonne, Illinois, has calculated that a previously unexplored symmetron regime near the dark energy scale will give rise to a fifth force at submillimeter distances. He proposes that short-range gravity experiments can search for the fifth force at these distances and possibly reveal if dark energy is in fact a symmetron field.”Much of my work has focused on chameleon dark energy theories, and I really only started thinking about symmetrons last summer,” Upadhye told “Modern experimental techniques and technologies have advanced enough to search for new physics at distances of interest for dark energy theories.”As Upadhye explained, a symmetron field could fulfill the role of dark energy by acting as a negative pressure.”Dark energy in general can be described by a constant (or slowly varying) vacuum energy density, such as that due to a field whose potential is minimized at a small, positive value,” he said. “In the presence of such an energy density, Einstein’s equation of General Relativity (GR) predicts that the universe will expand at an accelerating rate. In GR, pressure gravitates; positive pressures contribute to the decelerating expansion of the universe. Dark energy acts as a negative pressure which leads to an accelerating expansion.”The simplest model of a dark energy is Einstein’s cosmological constant, a constant vacuum energy density which explains all available data. The big question in cosmology is whether or not the dark energy is just a cosmological constant. Alternative theories predict that the vacuum energy density evolves with time, or that new (‘fifth’) forces exist between known particles. 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

Oil searchers discover and record deepsea graveyard off Angola coast

first_img © 2014 A team of researchers looking for oil and gas deposits beneath the seafloor off the western coast of southern Africa has found four large “fish-falls” on the seabed: the carcasses of one whale shark and three mobulid rays. Finding vertebrate carcasses on the seafloor is quite rare, ocean scientists Nicholas Higgs, Andrew Gates and Daniel Jones report in their paper on the discovery published in PLoS ONE—the “graveyard” offers a unique opportunity to learn more about how the death of large sea creatures and the food they provide to other smaller creatures impacts marine life in general. Still images showing each of the observed carcasses. A Whale shark (Rhincodon typus); B Mobulid carcass 1; C Mobulid carcass 2; D Mobulid Carcass 3. Images have been enhanced. Credit: PLoS ONE, doi:10.1371/journal.pone.0096016.g002 Citation: Oil searchers discover and record deep-sea graveyard off Angola coast (2014, May 16) retrieved 18 August 2019 from Antarctica’s first whale skeleton found with nine new deep-sea species To date, just nine vertebrate carcasses have ever been found and studied on the deep ocean floor—this recent discovery pushes that number to thirteen. Such carcass remains are categorized by “fall” type. These four were all fish falls, other’s such as whale falls generally attract more attention.Recorded along with the carcasses were scavengers that had arrived at the scene to feast on the large creatures’ remains. The researchers note that quite often the first to arrive at a fall of any sort are sharks, though they rarely consume what has been found. Next to find the carcasses are usually crabs and amphipods and at some point osedax that feed on the bones. In the footage the researchers were able to see large numbers of fish surrounding the carcasses, the majority of which were eel pouts, which don’t eat carcass remains, but instead feed on other fish that do. The researchers noted that no evidence of osedax were present which suggested that the carcasses hadn’t been on the sea floor very long, perhaps just a month or two. Explore further Journal information: PLoS ONE More information: Higgs ND, Gates AR, Jones DOB (2014) Fish Food in the Deep Sea: Revisiting the Role of Large Food-Falls. PLoS ONE 9(5): e96016. DOI: 10.1371/journal.pone.0096016AbstractThe carcasses of large pelagic vertebrates that sink to the seafloor represent a bounty of food to the deep-sea benthos, but natural food-falls have been rarely observed. Here were report on the first observations of three large ‘fish-falls’ on the deep-sea floor: a whale shark (Rhincodon typus) and three mobulid rays (genus Mobula). These observations come from industrial remotely operated vehicle video surveys of the seafloor on the Angola continental margin. The carcasses supported moderate communities of scavenging fish (up to 50 individuals per carcass), mostly from the family Zoarcidae, which appeared to be resident on or around the remains. Based on a global dataset of scavenging rates, we estimate that the elasmobranch carcasses provided food for mobile scavengers over extended time periods from weeks to months. No evidence of whale-fall type communities was observed on or around the carcasses, with the exception of putative sulphide-oxidising bacterial mats that outlined one of the mobulid carcasses. Using best estimates of carcass mass, we calculate that the carcasses reported here represent an average supply of carbon to the local seafloor of 0.4 mg m−2d−1, equivalent to ~4% of the normal particulate organic carbon flux. Rapid flux of high-quality labile organic carbon in fish carcasses increases the transfer efficiency of the biological pump of carbon from the surface oceans to the deep sea. We postulate that these food-falls are the result of a local concentration of large marine vertebrates, linked to the high surface primary productivity in the study area. Because fall finds are so rare, researchers have resorted to dropping dead animals into the ocean and then studying what happens—finding four such natural carcasses is unprecedented, leading to questions as to why so many of the animals died seemingly at the same time. The researchers suggest the graveyard may not be as rare as the finding would suggest, as its possible many exist but have simply not been found—the ocean floor is a vast expanse after all, and the chances of happening upon a fall while studying any given section of sea floor would be slim. Despite that, many must exist as many sharks, rays, whales, exist in the sea and they all must die at some point. Scientists estimate that as much as 4 percent of food in the ocean comes from falls—the rest is in the form of marine snow. 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

Researcher figures out how sharks manage to act like math geniuses

first_img Explore further Citation: Researcher figures out how sharks manage to act like math geniuses (2014, September 17) retrieved 18 August 2019 from ( —Bioresearcher Andy Reynolds with Rothamsted Research in the U.K., believes he has solved the mystery of how sharks act like math geniuses—they simply turn away from turbulence, he reports in his paper published in the journal Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences. His research effort and paper came in response to prior research that showed sharks trap prey using what’s known as Lévy flight—a mathematical description of an optimal way of moving from one position to another using both long and short hops. Great white shark at Isla Guadalupe, Mexico, August 2006. Credit: Terry Goss/Wikipedia By most simple measures, sharks are not the smartest swimmers in the sea, yet, they have somehow managed to learn to use Lévy flight when chasing prey, optimizing energy use in the process. So, how do they do it? Reynolds claims its more reaction than thought and believes his computer simulations prove it. Normally responsible for investigating or developing models of insect movement patterns over terrain, Reynolds in this case, turned his attention to the way sharks and some other sea creatures move through their environment when chasing prey. After learning that many of them use Lévy flight, he sought to find out why.Lévy flight actually makes sense for predators, he found, it’s based on movements that can be used to gain the most amount of resources for the least amount of effort. Reynolds suspected sharks wind up using it due to turbulence in the water. Turbulence, he notes, is not conducive to efficient swimming. He turned to a part of turbulence theory which suggests that Lévy flights can arise naturally if a chaser (the shark) turns away from the direction of unusually strong turbulence. He took what he’d worked out with his math calculations and translated it to a computer model of shark movement. When run, the simulation showed the theories matched perfectly with real world observations. Sharks, it seems, are not great thinkers, instead, they merely appear to be so by simply avoiding messy turbulence.Reynolds’ results show that seemingly intelligent behavior in other animals may not be what it appears, and thus researchers and others observing such behaviors should consider the possibility that other factors may be at play. © 2014 Jellyfish food-finding strategy found to be more complex than thought 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: Lévy flight movement patterns in marine predators may derive from turbulence cues, Proc. R. Soc. A 8 November 2014 vol. 470 no. 2171 20140408, DOI: 10.1098/rspa.2014.0408 AbstractThe Lévy-flight foraging hypothesis states that because Lévy flights can optimize search efficiencies, natural selection should have led to adaptations for Lévy flight foraging. Some of the strongest evidence for this hypothesis has come from telemetry data for sharks, bony fish, sea turtles and penguins. Here, I show that the programming for these Lévy movement patterns does not need to be very sophisticated or clever on the predator’s part, as these movement patterns would arise naturally if the predators change their direction of travel only after encountering patches of relatively strong turbulence (a seemingly natural response to buffeting). This is established with the aid of kinematic simulations of three-dimensional turbulence. Lévy flights movement patterns are predicted to arise in all but the most quiescent of oceanic waters.last_img read more

Trees found to break at near the same wind speed regardless of

first_img Journal information: Physical Review E (—A small team of researchers with École Polytechnique in France has found that all trees, regardless of size or species, tend to break at near the same wind speed. In their paper published in Physical Review Letters, the team describes tests they conducted in a lab and how they came up with a scaling law to describe the point at which a tree will break due to wind stress. Trees employ similar strategies to outcompete their neighbors © 2016 People have noticed for some time that when high winds strike, trees, regardless of size, age or species all seem to snap in a given area—but only when the wind reaches some given speed. Up until now, it has not been clear if all trees snap at the same wind speed, or if there is a gradient of sorts. To find out, the researchers in France conducted experiments where they attached water buckets to wooden rods to measure both their flexibility and the point at which they would break. In so doing, the team found that the rods tended to break at near the same point. Next, the team combined their lab experiments with data collected by others over time that suggested that trees tend to snap when wind speeds reach approximately 42 meters per second. Using all the information at hand, the team came up with a scaling law to describe when a tree will break due to wind force: (V∼D0.75/L), where V is wind velocity, D is diameter of the wood and L is its length. When applied to trees, rather than just rods, the team found that variance due to physical differences between species was minimal—doubling the size of the tree, for example, made a difference of just 9 percent, and oak trees, notorious for their strength broke at speeds just 10 percent higher than pine.The researchers explain that the size of a tree does not play a bigger role because they grow at a rate where their height is proportional to diameter, and because the larger a tree grows the more defects in the wood come into play—also as a tree grows larger, more and more of its surface area is exposed to wind forces. Citation: Trees found to break at near the same wind speed regardless of size or species (2016, February 10) retrieved 18 August 2019 from 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 Breakage induced by torsion. (a) A tree broken after a trunk torsion. (Photograph: Keraunos, Fontainebleau forest, France, June 2010). (b)–(e) Snapshots from experiments. Wood rod of length L=900 mm and diameter D=4 mm. Snapshots are stretched vertically to emphasize the deformation out of its axis (note the two scale bars). Credit: (c) Physical Review E (2016). DOI: 10.1103/PhysRevE.93.023001 , Physical Review Letters More information: E. Virot et al. Critical wind speed at which trees break, Physical Review E (2016). DOI: 10.1103/PhysRevE.93.023001ABSTRACTData from storms suggest that the critical wind speed at which trees break is constant (≃42m/s), regardless of tree characteristics. We question the physical origin of this observation both experimentally and theoretically. By combining Hooke’s law, Griffith’s criterion, and tree allometry, we show that the critical wind speed indeed hardly depends on the height, diameter, and elastic properties of trees.last_img read more

Vietnamese treat for Delhiites

first_imgThe easternmost part of Asia just got closer to the Capital. How? On the occasion of Vietnam Cultural Days in India celebration, Indian Council for Cultural Relations (ICCR) and the Embassy of Vietnam staged a cultural performance of Vietnam’s music, dance, song and theatre.Attended by VU Van Ninh, prime minister of Vitenam and Ambassador Nguen Than Tan, the event was held at Rashtrapati Bhawan in collaboration with Premjit Singh Manipuri and the Vietnam National Music, Song and Dance Theatre. Also Read – ‘Playing Jojo was emotionally exhausting’Established in 1951, the national Vietnamese theatre group is a part of the Ministry of Culture, Sport and Tourism of Vietnam. Since then it has brought together multifarious artistes in the fields of national folk music, dance and song under one roof.The group has won many accolades at both national and international levels and has performed across the country at many festivals. It now comes to Delhi to showcase its best of the talent and art.‘The cultural festival provides a stable foundation for our interactions in tangible areas related to economy, commerce and politics in Vietnam. The gala celebration demonstrates the shared traditions between India and Vietnam,’ said Dr Suresh K Goel, Director General, ICCR. Also Read – Leslie doing new comedy special with Netflix‘The Theatre group artists have been officially trained at domestic and international music institutions. There are nearly 61 ethnic minority people groups in Vietnam that forms the crux of the team and hone their talent at a nascent age,’ said Nguyen Than Tan, Ambassador of Vietnam to India.The celebrations will continue to spread its fervour and flavour in the coming days with many events. They include Vietnam Lotus Dance (H?n Sen Vi?t) which is about the journey of a lotus bud to a full-grown flower and like India, Vietnam also considers lotus as its National flower. Second on the list is a flute music performance called H?n hò, meaning Dating. It’s about creating that sacred bond between nature and human beings.Also a duet song will be performed by both Vietnamese and Indian artistes together called Tuong phùng tuong ng? (Whenever we meet each other) and Pal pal ha pal. The song signifies the spirit and sharing of goodwill whenever we meet each other.The ceremony will be closed with Chi?u d?i ngàn (The immensity of the Central Highlands in the afternoon), a musical evening taking you on a trip to Vietnam central Highland which is endowed with beauty of mother nature.Go for this festival to find out more about Vietnam and get enthralled.DETAILAt: ICCR Azad Bhawan, IP Estate When: 9 JanuaryTimings: 6.30 pmlast_img read more

Conquering the phase

first_imgThe winner of the prestigious TERI under Project Search Phase V award were announced on 28 April where Chiranjiv Bharati School, Sushant Lok bagged first prize for best performing school in various activities throughout  the year 2013-14 transition campaign – Inspire.Anushyas Kumar was selected as the fifth Tetrapak Ambassador and Ananyaq Veearun as STEP member. There are about 200 schools across the country who are part of this project. The first award was given by Jaideep Gokhale, communication director, Tetra Pak, South Asia Markets and the management award was given by Praveen, Environment Manager, Tetrapak, South Asia Markets.School Management was also awarded the Search Pillar Award for its continuous support towards working for the environment cause and sensitizing the community about the same.last_img read more

Folk goes beyond borders

first_imgWords and languages are not barriers when music runs in your soul. British Council’s collaborative programme Folk Nations is a proof of it. With an amalgamation of tunes from Wales, Scotland, England and India, Folk Nations left the audience wanting for more. The event was organised by The British council and Indian Council of Cultural relation (ICCR) at the Kamani auditorium on Wednesday evening.In early 2013 British Council and the English Folk Dance and Song Society (EFDSS) ran a residency workshop in Kolkata inviting a group of UK and Indian folk musicians to share their folk music tradition and collaborate in a week of immense music making. What emerged was a group of six gifted musicians –  Patsy Reid (Scotland), Hannah James (England), Georgia Ruth (Wales), Saurav Also Read – ‘Playing Jojo was emotionally exhausting’Moni (India), Suhail Yusuf Khan (India) and James Mackintosh (Scotland). Their group represents a delicate weaving of UK and Indian folk that speaks immediately to the cultural heritage of these regions as well as its place in the contemporary music industry. Be it Suhail Yusuf Khan’s beautiful folk song Rangi saari gulabi chunariya re with Patsy Reed’s Scottish tunes in perfect sync to it, or Hannah James melancholy number The Three Ravens, with Suhail’s Indian alaaps, the folk music of different countries interwoven together left the audience amazed. Also Read – Leslie doing new comedy special with NetflixAttar Singh, an advocate, who had come to Kamani auditorium to witness the show said, ‘It is a very good initiative. It’s exciting to listen to music from different lands and how they have been interwoven with Indian folk. The approach is non-traditional but the music is traditional from each of these nations.’The audience, which consisted of many British expatriates, were tapping their feet and clapping along when Saurav Moni performed his song written on a heady draught of Bengal, Allah megh de, Paani de, Chhaya de Tui. The engaging evening ended with Saurav Moni’s song of rowing of the boats Haiyyo re haiyyo with Hannah James performing a tap dance to the tune. Songs of love and death, of romance and life sung in different languages and with foreign tunes left the audience moved. The performance will be repeated on the 17 October in Kolkata and in Shillong on the 19 October.last_img read more

No election around Popes Visit to Sri Lanka Roman Catholic church

first_imgThe Roman Catholic church in Sri Lanka says it has asked the government to ensure that the country’s presidential election does not conflict with Pope Francis’ visit to the country early next year.While a date has not been set, the government has said it wants to hold an election sometime in January. Pope Francis is to arrive in the island nation on January 13.The Reverend Fernando, the spokesman for the pope’s visit, said on Monday the church has told the government that Pope Francis won’t visit a country during an election campaign, and that there should be enough time between a possible election and the visit. During his trip, Pope  is scheduled to lead the canonization Mass for S Lanka’s first saint.last_img read more

Acid thrown from taxi at passerby six injured

first_imgKolkata: Six persons, including five women in their early 20s, were injured when unidentified persons allegedly threw some chemical, supposedly acid, at them from a moving taxi last night at Panditia Road in the southern part of the city, police said today. The victims were passersby and the incident took place around 9.30 pm last night, the police said.Locals chased the yellow taxi but the riders including the driver escaped leaving the vehicle behind, a senior officer of Kolkata Police said. Also Read – Heavy rain hits traffic, flights”They (people in the car) attacked the people indiscriminately and randomly and no one was the target, in particular,” he added.Kolkata Police Deputy Commissioner (South) Meeraj Khalid said, “We have intercepted the taxi. A case has been lodged at Rabindra Sarovar police station. We are talking to the witnesses and the victims. We will soon arrest the culprits.” “We are yet to get hold of the driver Ricky Mondal, who was appointed by the owner. We found the room where he was staying in Kalighat area under lock and key. We have launched a search for him,” the investigating officer. Also Read – Speeding Jaguar crashes into Merc, 2 B’deshi bystanders killed”Going by the eye witnesses version it seems there were around four to five men inside the taxi. We have asked for the CCTV footages of the area,” he added.A case was lodged at the Rabindra Sarovar police station and a search has been launched for the attackers using the vehicle’s registration number, he said.The injured were discharged after preliminary treatment at a state-run facility.Police were trying to find out the nature of the chemical which was allegedly hurled at the victims.”We have collected samples of the liquid from the spot and send it for testing at the laboratory. We are not sure whether the liquid was acid because there were no serious injuries on the victims. They only complained of a burning sensation,” the police officer added.last_img read more