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Category: computing – Page 688

Approximately every two Earth years, when it is summer on the southern hemisphere of Mars, a window opens: Only in this season can water vapor efficiently rise from the lower into the upper Martian atmosphere. There, winds carry the rare gas to the north pole. While part of the water vapor decays and escapes into space, the rest sinks back down near the poles. Researchers from the Moscow Institute of Physics and Technology and the Max Planck Institute for Solar System Research (MPS) in Germany describe this unusual Martian water cycle in a current issue of the Geophysical Research Letters. Their computer simulations show how water vapor overcomes the barrier of cold air in the middle atmosphere of Mars and reaches higher atmospheric layers. This could explain why Mars, unlike Earth, has lost most of its water.

Billions of years ago, Mars was a planet rich in water with rivers, and even an ocean. Since then, our neighboring planet has changed dramatically. Today, only small amounts of frozen water exist in the ground; in the atmosphere, water occurs only in traces. All in all, the planet may have lost at least 80 percent of its original water. In the upper atmosphere of Mars, ultraviolet radiation from the sun split water molecules into hydrogen (H) and hydroxyl radicals (OH). The hydrogen escaped from there irretrievably into space. Measurements by space probes and space telescopes show that even today, water is still lost in this way. But how is this possible? The middle atmosphere layer of Mars, like Earth’s tropopause, should actually stop the rising gas. After all, this region is usually so cold that water vapor would turn to ice. How does the Martian water vapor reach the upper air layers?

In their current simulations, the Russian and German researchers find a previously unknown mechanism reminiscent of a kind of pump. Their model comprehensively describes the flows in the entire gas envelope surrounding Mars from the surface to an altitude of 160 kilometers. The calculations show that the normally ice-cold middle atmosphere becomes permeable to water vapor twice a day—but only at a certain location, and at a certain time of year.

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The world’s first virtual reality gym just opened in San Francisco, offering a next-generation workout via a computer games-based distraction technique that aims to put the fun back into exercising.

Black Box VR promises a gym experience like no other by giving users a full-body workout while virtually immersed in another world that requires them to fight battles and beat their opponent.

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Videogames show us how digital media in general lend themselves easily to flow. For flow experiences often depend on repetitive actions, which contribute to the feeling of engagement and absorption that Csikszentmihalyi describes, and videogames—like all interactive computer interfaces, indeed like virtually all computer programs—operate on the principle of repetition. The user becomes part of the event loop that drives the action: her inputs to the controller, mouse, or keyboard are processed each time the computer executes the loop and are displayed as actions on the screen. The user not only experiences flow, she actually becomes part of the program’s flow. This is true, if in different ways, for applications throughout digital culture, such as YouTube, Facebook, and Twitter.

The most prominent and popular social media platforms appeal to their hundreds of millions of users in part through the mechanism of flow. The stereotype, which contains some grain of truth, is that flow culture is youth culture. Young people spend their days immersed in flows of text messages, tweets, Facebook posts, and streaming music, while older adults prefer to experience their media one at a time. For example, a Pew Research survey from 2012 showed that almost half of all adults between ages 18 and 34 use Twitter, whereas only 13 percent of adults over age 55 do. The younger you are, the more likely you are to multitask: those born after 1980 do so more than Generation X, which does so much more than the baby boomers.

Each of the genres of social media provides a different flow experience. YouTube, for example, remediates television and video for the World Wide Web. A typical YouTube session begins with one video, which the user may have found through searching or as a link sent to her. The page that displays that video contains links to others, established through various associations: the same subject, the same contributor, a similar theme, and so on. Channel surfing on traditional television can be addictive, but the content of one channel tends to have little to do with that of the next. YouTube’s lists of links and its invitation to search for new videos give the viewer’s experience more continuity, with the opportunity to watch an endless series of close variants.

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A rise in the number of game developers, adoption of brain computer technology to enhance the complete gaming experience is triggering the growth of BCI market. The BCI application in 2017 has also influenced the smart home control sector and is believed to grow rapidly during the forecast period of 2018 to 2025. The high living standards across U.S and Canada are held responsible for the demand of BCI in smart home control system industry.

Brain-computer interface (BCI) is a technology that agree to communicate between a human-brain with an external technology. The term can be referred to an interface that takes signals from the brain to an external piece of hardware that sends signals to the brain. There are different brain-computer interface technologies developed, through different methods and for diversified purposes, including in virtual reality technology.

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Majorana particles are very peculiar members of the family of elementary particles. First predicted in 1937 by the Italian physicist Ettore Majorana, these particles belong to the group of so-called fermions, a group that also includes electrons, neutrons and protons. Majorana fermions are electrically neutral and also their own anti-particles. These exotic particles can, for example, emerge as quasi-particles in topological superconductors and represent ideal building blocks for topological quantum computers.

Going to two dimensions

On the road to such topological quantum computers based on Majorana quasi-particles, physicists from the University of W\xFCrzburg together with colleagues from Harvard University (USA) have made an important step: Whereas previous experiments in this field have mostly focused on one-dimensional systems, the teams from W\xFCrzburg and Harvard have succeeded in going to two-dimensional systems.

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Gazibegović, Ph.D. candidate in the group of prof. Erik Bakkers at the department of Applied Physics, developed a device made of ultrathin networks of nanowires in the shape of “hashtags.” This device allows pairs of Majorana particles to exchange position and keep track of the changes occurred, in a phenomenon known as “braiding.” This event is considered as a striking proof of the existence of Majorana particles, and it represents a crucial step towards their use as building blocks for the development of quantum computers. With two Nature publications in her pocket, Gazibegović is ready to defend her Ph.D. thesis on May 10.

In 1937, the Italian theoretical physicist Ettore Majorana hypothesized the existence of a unique particle that is its own antiparticle. This particle, also referred to as a “Majorana fermion,” can also exist as a “quasiparticle,” a collective phenomenon that behaves like an individual particle, as in waves forming on the water. The water itself stays in the same place, but the wave can “travel” on the surface, as if it were a single particle in movement. For many years, physicists have been trying to find the Majorana particle without success. Yet, in the last decade, scientists from Eindhoven University of Technology have taken great leap forwards in proving the existence of Majorana particles, also thanks to the research of Gazibegović and her collaborations with the University of Delft, Philips Research and the University of California – Santa Barbara.

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Researchers at Johannes Gutenberg University Mainz (JGU) have succeeded in developing a key constituent of a novel unconventional computing concept. This constituent employs the same magnetic structures that are being researched in connection with storing electronic data on shift registers known as racetracks. In this, researchers investigate so-called skyrmions, which are magnetic vortex-like structures, as potential bit units for data storage. However, the recently announced new approach has a particular relevance to probabilistic computing. This is an alternative concept for electronic data processing where information is transferred in the form of probabilities rather than in the conventional binary form of 1 and 0. The number 2/3, for instance, could be expressed as a long sequence of 1 and 0 digits, with 2/3 being ones and 1/3 being zeros. The key element lacking in this approach was a functioning bit reshuffler, i.e., a device that randomly rearranges a sequence of digits without changing the total number of 1s and 0s in the sequence. That is exactly what the skyrmions are intended to achieve. The results of this research have been published in the journal Nature Nanotechnology.

The researchers used thin magnetic metallic films for their investigations. These were examined in Mainz under a special microscope that made the magnetic alignments in the metallic films visible. The films have the special characteristic of being magnetized in vertical alignment to the film plane, which makes stabilization of the magnetic skyrmions possible in the first place. Skyrmions can basically be imagined as small magnetic vortices, similar to hair whorls. These structures exhibit a so-called topological stabilization that protects them from collapsing too easily – as a hair whorl resists being easily straightened. It is precisely this characteristic that makes skyrmions very promising when it comes to use in technical applications such as, in this particular case, information storage. The advantage is that the increased stability reduces the probability of unintentional data loss and ensures the overall quantity of bits is maintained.

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In a recent study now published in Light: Science & Applications, Ming Zhang, Lan-Tian Feng and an interdisciplinary team of researchers at the departments of quantum information, quantum physics and modern optical instrumentation in China, detailed a new technique to generate photon-pairs for use in quantum devices. In the study, they used a method known as four-wave mixing to allow three electromagnetic fields to interact and produce a fourth field. The team created the quantum states in a silicon nanophotonic spiral waveguide to produce bright, tunable, stable and scalable multiphoton quantum states. The technology is comparable with the existing fiber and integrated circuit manufacturing processes to pave the way to engineer a range of new generation photonic quantum technologies for applications in quantum communication, computation and imaging. The multiphoton quantum sources detailed in the work will play a critical role to improve the existing understanding of quantum information.

The scientists generated multiphoton quantum states using a single-silicon nanophotonic waveguide and detected four-photon states with a low pump power of 600 µW to achieve experimental multiphoton quantum interference verified with quantum state tomography. Zhang and Feng et al. recorded the quantum interference visibilities at a value greater than 95 percent with . The multiphoton quantum source is fully compatible with on-chip processes of quantum manipulation and quantum detection to form large-scale quantum photonic integrated circuits (QPICs). The work has significant potential for multiphoton quantum research.

Multiphoton quantum sources are critical to build several practical platforms for quantum communication, computation, simulation and metrology. Physicists have made great efforts to realize high quality, bright and scalable multiphoton quantum states in previous work, to activate powerful quantum technologies by multiplexing several biphoton sources to generate eight-photon and 10-photon entanglement. However, the efficacy of such multiplexing systems decreased with the number of entangled photons. At present, quantum photonic integrated circuits (QPCIs) and silicon-on-insulator (SOI) technology remain promising to realize high quality photon-pair sources.

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