Explore further Daley is a physicist in the Institute for Theoretical Physics at the University of Innsbruck and the Institute for Quantum Optics and Quantum Information of the Austrian Academy of Sciences in Austria. He, along with Martin Boyd and Jun Ye at the University of Colorado, and Peter Zoller at Innsbruck, are proposing a quantum computing scheme that would make use of overlaying optical lattices to store information as well as perform computations. Much of this work was performed when the authors were guests at the California Institute of Technology in Pasadena, and their ideas are shared in Physical Review Letters: “Quantum Computing with Alkaline-Earth-Metal Atoms.”Electrons play a vital role in quantum computing with atoms, and when atoms are controlled with light, the electrons are also controlled. “That’s what makes alkali atoms nice to deal with,” says Daley. “They only have one valence electron, which makes the system really simple.” He then points out that alkaline earth metals offer an advantage over alkali atoms: “There are two electrons weakly bound. Even though the system is a little more complicated, there are some very nice properties.”Daley explains that it is possible to excite an electron to higher energy states in which they remain for a relatively long time. “The idea is to create two different traps using two different colors of light, one for atoms where the electron is excited and the other for atoms where it is not. This is possible because the atoms react to light, and go where the light is. Basically, we can make an array of bright spots of laser light – an optical lattice – where there is an atom in every bright spot.”In order to store information, Daley says, the spin of the nucleus is adjusted, also with laser light. “Atoms are initially stored in the lattice for the state where the electron is not excited. They can then be transferred to the state with an excited electron and transported to different parts of the system by moving the two different traps relative to each other. This can be used to perform computations with information stored on atoms in different parts of the lattice.”The paper Daley and his peers wrote expresses theory rather than describing the results of an experiment. However, it is possible that a demonstration might be possible fairly soon. “While this paper is theoretical,” he insists, “we build on techniques demonstrated in the laboratory, making use of technology that is currently applied to make atomic clocks.”Some of the details still need to be worked out, but Daley feels that it should be possible to build something workable to demonstrate the principle in the relatively near future. “We’ve taken our ideas of what can be done and matched them up with real numbers from experiments. This could lead to the first few steps and then be refined to make larger quantum computations.”“Our paper is a type of road map to set a course for what could be possible,” Daley continues. “We believe that with our technology it is likely that the first demonstrations are feasible on a timescale of two to three years.”More Information: Andrew Daley, Martin Boyd, Jun Ye and Peter Zoller. “Quantum Computing with Alkaline-Earth-Metal Atoms,” Physical Review Letters (2008). Available online: link.aps.org/abstract/PRL/v101/e170504. 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. Citation: Can alkaline earth metals be used in quantum computing? (2008, November 14) retrieved 18 August 2019 from https://phys.org/news/2008-11-alkaline-earth-metals-quantum.html (PhysOrg.com) — “There are a number of different proposals for quantum computing,” Andrew Daley tells PhysOrg.com. “These include solid state or semiconductor as well as atomic and molecular systems. We are considering atomic systems, and more specifically alkaline earth metals.” Quantum simulation could help flights run on time
(PhysOrg.com) — Will the legacy of Nobel prize winner Richard Smalley finally be fulfilled? Ever since his pioneering work in the mid 1990’s on the synthesis of carbon nanotubes, companies have been struggling to find a commercial application for this amazing material. There was a nanotech “bubble” of start-up companies, none of which managed to successfully IPO due to lack of realizable commercial revenue. Is that about to change? Recent research by Rice University and Unidym indicate that a fully realizable application is finally here for carbon nanotubes. Fortunately, it’s in one of the fastest growing display markets, touch screens. Citation: Transparent Carbon Nanotube Films Likely Successor to ITO for Commercial Applications (2009, April 10) retrieved 18 August 2019 from https://phys.org/news/2009-04-transparent-carbon-nanotube-successor-ito.html Carbon nanotubes (CNTs) are tiny hollow cylinders of carbon with tremendous electrical and optical properties. It turns out that very thin CNT films as thin as 10 or 20 nanometers are transparent to visible light and can conduct enough electricity to make them useful for many applications where these properties are needed. These applications include thin film solar cells, organic LEDs, and touch screens. Currently, a ceramic material called indium tin oxide (ITO) is used in these applications. This material is deposited in vacuum and is quite brittle. Carbon nanotubes, on the other hand, can be deposited from solution, and are remarkably robust and flexible. Films can be coated about 50 times faster than ITO films, and are almost unbreakable when flexed, tapped, strained, or smashed with a hammer, while ITO films are brittle and easy to crack under strain. Researchers predict that the first applications for these transparent CNT films will be as the electrodes in touch screens. This is because they already meet all technical requirements, and ITO has an issue in that it tends to crack after repeated use, thus degrading the touch screen response. Touch screens are a rapidly expanding market due to the popularity of the iPhone amongst other devices. By the end of the year, CNT films will begin to replace ITO in touch screens. As the technology continues to improve it will continue to take market share from ITO. This will be a remarkable achievement, and may issue in a new day for carbon nanotubes in various markets. I think Smalley would be pleased.More information can be found in: “Continuous and Scalable Fabrication of Transparent Conducting Carbon nanotube Films” by Dan, Irvin, and Pasquali in ACS Nano, published on the web April 08, 2009.© 2009 PhysOrg.com Will carbon nanotubes replace indium tin oxide? Explore further Flexible carbon nanotube film on plastic. Photo courtesy of Unidym. 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: www.thameswater.co.uk/ Explore further Citation: Britain unveils desalination plant for London reservoirs (2011, April 25) retrieved 18 August 2019 from https://phys.org/news/2011-04-britain-unveils-desalination-london-reservoirs.html Reverse osmosis water purification is a filtration process whereby brackish water is pressurized in a tank which pushes it through a thin membrane, allowing only the pure water to emerge out the other side. Because of the extra energy needed for pressurization, reverse osmosis generally costs up to twice as much as regular purification processes, which in turn causes taxpayers, especially in such a wet climate as Britain, to wonder about the wisdom of installing such a plant.But Thames Water, the company in charge of supplying drinking water to London, believes such a plant will be necessary in the future, citing the water restrictions put in place during the last extended drought in 2005/06, which was a catalyst for the construction of the plant. Critics have been quick to point out, however, that had the water company fixed its leaking pipes, some of the worst in the world, there would not have been a need for a new plant at all.Construction of the plant was finished in June of last year, but it wasn’t until just last month that the plant began actively pumping clean water into nearby reservoirs, albeit at only one sixth capacity. Simon Evans, spokesman for Thames Water, claims they are only doing so to test the system and train workers. The idea after all, is to fill the reservoirs if they fall low due to lack of rainfall, which coincidently or not, is exactly what Britain has been experiencing this spring.It’s likely the construction of the plant will cause other metropolitan areas to take notice as city planners the world over fall victim to criticism from thirsty city dwellers who suddenly find themselves at the mercy of varying weather patterns. Traditionally reverse osmosis plants have been built for areas with few other options, such as those in the Middle East; with this new plant in London, however, that could change. © 2010 PhysOrg.com (PhysOrg.com) — Britain has brought online a new desalination plant near London capable of providing the city with 150 million gallons (568 million litres) of water per day, should the need arise. At a cost of £270 ($445) million, and built over the past four years, the plant uses reverse osmosis to remove salt from the brackish water pumped in from the Thames Estuary, which it then pumps into local reservoirs, thus staving off the threat of drought. Controversy surrounds British water plant Aerial view of Farmoor Reservoir, Oxfordshire 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.
For TEM observation, K2PtCl4 was first dissolved in deionized water in preparation to image its crystal structure. In the bright field TEM image, the crystallite was 50 nm x 60 nm in size. Gao et al. weakened the electron beam dose to the angstrom scale for less than 1 e/A2∙s to limit beam-induced sample reduction during the process of imaging. The scientists conducted high-resolution electron microscopy (HREM) at 300,000 x magnification to obtain 64 images from the same area. By averaging the images, the atomic columns were clearly resolved in the study. The high-resolution TEM image showed periodic lattice squares with an atom (yellow) surrounding those without bright atomic contrast (blue) in the center. Gao et al. compared the atomic resolution images with the existing atomic structure of K2PtCl4 to identify each individual element. The scientists identified the atoms in the corners as potassium (K), atoms in the middle of the edges of the squares as chlorine (Cl) and those in the center of the square in yellow as platinum (Pt). When Gao et al. increased the electron beam dose to 30 e/A2∙s, the lattice from K2PtCl4, which was originally viewed across the entire area developed into individual Pt clusters. In time, the nanoclusters grew more pronounced under the microscope. Low-dose atomic resolution imaging of K2PtCl4. (A) The atomic model of the K2PtCl4 unit cell, with K in cyan, Pt in purple, and Cl in pink. (B) Bright-field TEM image of a large K2PtCl4 crystallite. (C) Diffraction pattern of the K2PtCl4 crystallite in (B) after it is tilted along the (001) zone axis. (D) Atomic resolution low-dose TEM image of K2PtCl4. Dose fractionation was done using an electron dose of 1 e/Å2·s, with 0.1 s for each image. Sixty-four images were acquired, aligned, and averaged. The electron dose then becomes 6.4 e/Å2. The atomic model is overlaid in the inset. (E) Simulated HREM image of K2PtCl4 with a thickness of 12.3 nm. (F) A zoomed-in image of K2PtCl4 from a sub-area in (D), and the intensity line profile in arbitrary units (a.u.) from the red box, is shown in (G), where the intensity from Pt atoms is located between two Cl atoms. Credit: Science Advances, doi: 10.1126/sciadv.aau9590. In a recent study, now published in Science Advances, interdisciplinary materials scientists Wenpei Gao and co-workers in the USA and China, studied the reaction kinetics of a solid-state platinum (Pt) precursor compound. In the study, they used an aberration-corrected transmission electron microscope (TEM) combined with low-dose electrons and in situ imaging. The scientists imaged the beam-sensitive Pt precursor; potassium tetrachloroplatinate (II) (K2PtCl4), at the atomic resolution to determine the individual atoms (K, Pt and Cl) involved in the synthesis of platinum nanoclusters. Gao et al. captured the material’s transformation to Pt nanoclusters in real time to show three-stage reaction kinetics, including (1) breaking of the ionic bond, (2) formation of PtCl2 and (3) reduction of the divalent Pt to Pt metal nanoclusters. In the new method, the scientists combined techniques to understand the transformation of chemicals at the atomic scale in real time without damaging the substrates and provided a new platform to study reaction kinetics. Gao et al. captured, identified and revealed the dynamics at different stages of decomposition, reduction and nucleation of the material. The work allowed them to understand the transformation kinetics of platinum from precursor to nanocluster as a promising avenue to study atomic-scale reaction dynamics. Zoomed-in image and atomic model of K2PtCl4. (A) and (B) are the corresponding TEM image and atomic structure model of K2PtCl4. The squares colored in yellow have one Pt atom in the center, with Cl atoms on the edge centers and K atoms on the corners. The square in blue does not have a Pt atom in the center. Credit: Science Advances, doi: 10.1126/sciadv.aau9590 Composition analysis of the final product. (A to D) HAADF image and EDS maps of the final product of the in situ experiment and (E) EELS of the final product of the in situ experiment showing the existence of Cl and K. Credit: Science Advances, doi: 10.1126/sciadv.aau9590 Then PtCl42- decomposed into PtCl2 and Cl-, a reaction which had not previously been reported in experimental studies. Gao et al. revealed this process using FFT of the high resolution image under a low electron dose and high acquisition efficiency. On removal of the K species from the precursor, the lattice became unstable and compounds including PtCl2, KCl and Cl2 could move freely. When PtCl2 was reduced in to Pt, the molecules of Cl2 transitioned into the gas phase for removal from the TEM column. The zerovalent Pt species formed small nuclei or migrated and grew into large Pt nanoparticles.In this way, the scientists elegantly demonstrated the reduction kinetics in the study and illustrated the concept using atomic models. The observed findings of nucleation and reduction of Pt agreed with that of previously calculated free energy in the chemical reaction. This method can be applied to study additional material transformations in depth. The results will benefit the applications of nanostructures in nanophysics for new materials development, new energy processes in environmental remediation and in nanomedicine. More information: Wenpei Gao et al. Probing the dynamics of nanoparticle formation from a precursor at atomic resolution, Science Advances (2019). DOI: 10.1126/sciadv.aau9590 T. S. Ahmadi et al. Shape-Controlled Synthesis of Colloidal Platinum Nanoparticles, Science (2006). DOI: 10.1126/science.272.5270.1924 Clemens Burda et al. Chemistry and Properties of Nanocrystals of Different Shapes, Chemical Reviews (2005). DOI: 10.1021/cr030063a Younan Xia et al. Shape-Controlled Synthesis of Metal Nanocrystals: Simple Chemistry Meets Complex Physics?, Angewandte Chemie International Edition (2008). DOI: 10.1002/anie.200802248 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. , Science (I) Evolution of K2PtCl4 into Pt nanoparticles. (A) Sequential TEM images show the evolution of K2PtCl4 into Pt nanoparticles. A Pt nanoparticle nucleation process is shown in the zoomed-in images in (B), from the marked sub-area within the white dashed boxes in (A). The red contour lines indicate the edge of the newly formed Pt clusters. The region in yellow highlights the void area without lattice after the formation of a Pt cluster. (II) Sequential radial distribution function (RDF) during the transformation. (A) Time series diffractogram using FFT from sequential low-dose images. (B) RDF derived from the sequential diffractogram. Credit: Science Advances, doi: 10.1126/sciadv.aau9590 © 2019 Science X Network In colloid and synthetic chemistry, materials scientists aim to control the shape and size of nanoparticles to achieve the desired properties of electronic, optic and catalytic materials. Nanocluster nucleation is a key process of growth kinetics in the solid state of materials synthesis. Manipulating the kinetics has allowed the synthesis of a group of nanoparticles shaped as nanorods, nanocubes, octahedra, octopod-shaped nanoparticles, icosahedra and other surface features. , Angewandte Chemie International Edition Scientists develop method for observing nanocrystal formation at atomic resolution They then observed further formation of the Pt nanoclusters across extended time periods under low-dose imaging conditions. The scientists selected a sub-area of the sequential images and applied a fast Fourier transform (FFT) to discern the structure and the constituents. Gao et al. were able to obtain a time series of FFT patterns in the K2PtCl4 lattice, which also reflected the radial distribution function (RDF) (to find adjacent particles). The scientists then investigated the additional surface orientation of atoms in the material, aside from the Pt nanoclusters, to understand the location of K and Cl species. In the work, they used a series of imaging and analytical methods of materials science, starting with high-angle annular dark-field (HAADF) scanning transmission electron microscopy (STEM) and the 2-D energy-dispersive spectra (EDS) map to characterize the material. The results showed the signals from K and Cl in the background as evenly distributed across the area. When the scientists used electron energy loss spectroscopy (EELS) they further observed the existence of K and Cl from KCl, after the formation of Pt nanoparticles. Gao et al. gathered sufficient information from the reaction dynamics captured in real space via spectroscopy and characterization techniques in materials science. They proposed a microscopic process of reduction kinetics for K2PtCl4. Accordingly, the precursor K2PtCl4 first decomposed in to K+ and PtCl42- by breaking the weak ionic bond. Journal information: Science Advances A schematic showing the evolution of K2PtCl4 into Pt nanoparticles. (A) K2PtCl4, (B) dissociation of K+ and [PtCl4]2−, (C) further dissociation into PtCl2 and KCl, and (D) nucleation of Pt nanoparticles. Credit: Science Advances, doi: 10.1126/sciadv.aau9590. While nucleation is the initial step in materials synthesis, it is difficult to control nucleation kinetics without understanding how atoms interact. Platinum nanoparticles are usually synthesized in a liquid-phase reaction with C-H or Cl- as a precursor. During growth in such a system, the precursor is reduced by the reducing agent to form metal monomers with atomic arrangements based on metal-metal interactions. However, a microscopic mechanism that details the intermediate reaction steps is yet unavailable. As an alternative to materials synthesis in the liquid phase, nanostructures can also be grown in the solid phase. Studying the reduction process in the solid state can decipher materials transformation for fine control of materials synthesis. Understanding the kinetics of materials transformation from precursors to nanostructures at the atomic scale based on ionic bond breaking is therefore of considerable significance. The scientists opted to study the nucleation process in the solid phase without the liquid environment using characterization tools of X-ray nanodiffraction and TEM, which offered ultra-high resolution. The method resolved the evolving structures in real and reciprocal space, although the sensitivity of most chemical precursors to the electron beam due to photo illumination had previously made it nearly impossible to observe the initial atomic structure of the precursor. Explore further A key to materials synthesis is the ability to control the process of reduction kinetics and nucleation (phase transition) in materials. Understanding the reduction dynamics during the initial stage of material synthesis is limited due to the difficulty of investigating chemical reactions at the atomic scale. This is mainly because the chemical precursors used to synthesize materials can degrade when exposed to electron beams that are typically used to image compounds at atomic resolution. Citation: Investigating the dynamics of nanoparticle formation from a precursor at atomic resolution (2019, January 29) retrieved 18 August 2019 from https://phys.org/news/2019-01-dynamics-nanoparticle-formation-precursor-atomic.html , Chemical Reviews
© 2019 Science X Network Citation: Jupiter’s magnetic field could be moving Europa’s ocean (2019, March 12) retrieved 18 August 2019 from https://phys.org/news/2019-03-jupiter-magnetic-field-europa-ocean.html The Galileo spacecraft took this image of Europa, which is about the size of Earth’s moon, in 1996. Credit: NASA. Water plumes on Europa: Tasting an extraterrestrial ocean The researchers started by noting that Jupiter has a very strong magnetic field—strong enough to reach and impact its moons. They also noted that Europa’s underground ocean is salty. A magnetic field influencing a salty sea would result in the conduction of electricity, likely creating a jet stream in the ocean. To find out what sort of movement might occur and to uncover other possible impacts of the magnetic field on the moon’s ocean, the researchers created numerical simulations. The simulations showed a jet stream forming somewhere near the moon’s equator, moving as fast as a few centimeters per second and flowing opposite of the moon’s spin. Such an opposite flow, the researchers further noted, would result in stress on the moon’s surface, which could occasionally form cracks. This would explain the surface cracks observed on Europa by other researchers. They further note that not all of the energy from the magnetic field would be transferred to the ocean—some of it would dissipate off the moon, likely around the poles. And if that were the case, there would be evidence of the moon’s ice shell becoming thinner as melting water made its way to the surface. And again, that is just what has been observed—plumes of water spurting out from spots near the poles.The researchers suggest a jet stream on Europa could be compared to the Gulf Stream back here on Earth. Notably, our jet stream has been found to move compounds around in the ocean that are important for life. If Europa harbors life, its jet stream could be serving the same purpose. Explore further Journal information: Nature Astronomy A pair of researchers, one with École Normale Supérieure, the other Laboratory for Studies of Radiation and Matter in Astrophysics and Atmospheres has found evidence that Jupiter’s magnetic field could be causing a jet stream in Europa’s underground ocean. In their paper published in the journal Nature Astronomy, Christophe Gissinger and Ludovic Petitdemange describe their analysis of data from the Galileo spacecraft and what they found. More information: Christophe Gissinger et al. A magnetically driven equatorial jet in Europa’s ocean, Nature Astronomy (2019). DOI: 10.1038/s41550-019-0713-3 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.
Remember Stereo Nation? The band which took the pop happy 90s by storm with their single Don’t Break my Heart? Well, one half of the band, Tarseme Singh Saini, better known as Taz, recently regaled collegegoers in the Capital when he performed at the annual cultural fest of a management college. The final day of the two-day festival Verve 2k13 saw the British-born pop singer charm the audience with his performance at the Rohini campus of the college. Also Read – ‘Playing Jojo was emotionally exhausting’The performance rounded off a fest that saw students showcase their creativity and talent in areas like tattoo art, quizzing, collage making, photography and singing. Students also organised a fashion show to display their tastes in accouterment, and also showcased their culinary talents. The event was attended by students from different campuses of the institute and for students who danced their way through the night, it was an evening to remember.Fest time was clearly a happy time for these kids.
The first performance was by the Gupta brothers of the Maihar Gharana, Lakshay Mohan Gupta on sitar and Ayush Mohan Gupta on sarod along with renowned pakhawaj player Akhilesh Gundecha and tabla player Shubh Maharaj. Leading on was the next performer Tanmoy Bose. Second day of the festival witnessed the performances of Sanjeev Shankar and Ashwani Shankar followed by a vocal recital by Ayesha Thatte and Bharatanatyam by Rama Vaidyanathan.The third day of the festival marked performance of Odissi by Radhika Samson. Following performance was by Swarnima Gusain, Swarnima. The day concluded by the performance of Satwik Veena player Salil Bhatt.The last day had Namrta Rai presenting Prashanti in kathak and Amita Dalal presenting raga Janasammohini. The festival concluded with Carnatic Vocal recital by Vidwan Maharajapuram Ramachandran.
Kolkata: The infomercial that was telecast on different channels following the direction of Chief Minister Mamata Banerjee to sensitise buyers about the right quality of meat, has ensured a rise in its sale.The sale of both raw and cooked meat in eateries in the state had witnessed a huge drop, after the carcass meat row came to light in mid-April. Now, being aware of the steps needed to be taken to buy the right quality meat, people are now once again purchasing the same, after assessing its quality properly. Also Read – Speeding Jaguar crashes into Merc, 2 B’deshi bystanders killedThe state government had set up a high powered committee to evolve a foolproof mechanism to bring an end to the selling of carcass meat. Thepolice had also arrested the kingpin of the racket to completely uproot the menace.Besides taking the steps, the necessity of creating awareness among people was also felt by the state government, so that people get to know the right steps need to be taken to verify the quality of meat before buying.The Chief Minister had held a meeting with the task force in June and directed the concerned officials to take initiative for preparing an infomercial to create awareness among people. Also Read – Naihati: 10 councillors return to TMC from BJPThe Information and Cultural Affairs department took the initiative. Actors Prosenjit Chatterjee and Nusrat Jahan were roped in and a 50-second long film was prepared.The film, in which the Tollywood actors were found urging people to verify before buying that the packaged meat is certified by FSSAI (Food Safety and Standards Authority of India) and at the same time, not to pay heed to any rumours.The infomercial has helped the people know the steps that they must take to buy fresh meat and has also helped people come out of a panicky situation in terms of buying chicken or meat. According to an official of the state government, the telecast of the infomercial had been appearing for the past few weeks on television channels. “It (the infomercial) has become very effective as all aspects that people need to know to buy meat have been told in a nutshell and it was presented in a very simple way as well. It has helped people to pick up the information easily,” the official said.Though it would take some time to create awareness among the entire populace in the state, the Chief Minister’s initiative to telecast the infomercial on television channels has helped in regaining confidence of a large section of people.It may be recalled that the sale of chicken and meat preparations in eateries had dropped by around 40 percent, soon after the carcass meat row came to light. With constant monitoring by the local civic bodies in their respective areas, sale of stale meat has also been checked.When contacted, B P Gopalika, principal secretary, Animal Resources Development department, was not available for any comment.
“It is extremely distressing to hear about the lynching.How can one human being kill another human being. If you want to politicise the issue, you can do. But then for me it is a human point of view,” Hussain said.The critically acclaimed author was in the city to participate in the five-day CMS Vatavaran festival,