Doppler effect Change of wavelength caused by motion of the source An animation illustrating how the Doppler effect causes a car engine or siren to sound higher in pitch when it is approaching than when it is receding. The pink circles are sound waves. When the car is moving to the left, each successive wave is emitted from a position further to the left than the previous wave. So for an observer in front (left) of the car, each wave takes slightly less time to reach him than the previous wave. The waves "bunch together", so the time between arrival of successive wavefronts is reduced, giving them a higher frequency. Doppler effect of water flow around a swan For waves that propagate in a medium, such as sound waves, the velocity of the observer and of the source are relative to the medium in which the waves are transmitted. Development General and emitted frequency is given by: where is the velocity of waves in the medium; The frequency is decreased if either is moving away from the other. and
Google's Quantum Computer Proven To Be Real Thing (Almost) | Wired Enterprise The D-Wave computer housed at the USC-Lockheed Martin Quantum Computing Center in Marina del Rey, California. Photo: Mae Ryan/Wired Google bought one. So did Lockheed Martin, one of the world’s largest defense contractors. D-Wave, the company that built the thing, calls it the world’s first quantum computer, a seminal creation that foretells the future of mathematical calculation. No doubt, the argument will continue. “[Our research] rules out one type of classical model that has been argued as a proper description of the D-Wave machine,” Lidar says. ‘Our research rules out one type of classical model that has been argued as a proper description of the D-Wave machine. — Daniel Lidar The paper, Experimental Signature of Programmable Quantum Annealing, appears in the well-respected academic journal Nature Communications. This “qubit” can store a “0″ and “1″ simultaneously. The rub is building even a single qubit is difficult. “We call it an energy landscape,” he says. Dr.
You're Interacting With Dark Matter Right Now - Megan Garber ... But scientists have no idea how. Here's a little experiment. Hold up your hand. Now put it back down. In that window of time, your hand somehow interacted with dark matter -- the mysterious stuff that comprises the vast majority of the universe. Dark matter, in other words, is not merely the stuff of black holes and deep space. But if you did the experiment -- as the audience at Hooper's talk on dark matter and other cosmic mysteries did at the Aspen Ideas Festival today -- you didn't feel those million particles. It's everywhere. And yet, despite its mysteries, we know it's out there. Dark matter, in other words, is aptly named. And it also means, Massey pointed out, that for scientists, "the job security is great." You might be wondering, though: given how little we know about dark matter, how is it that Hooper knew that a million particles of the stuff passed through your hand as you raised and lowered it? "I cheated a little," Hooper admitted.
One-way mirror A one-way mirror, one-way glass, or two-way glass is a mirror that is partially reflective and partially transparent. When one side of the mirror is brightly lit and the other is dark, it allows viewing from the darkened side but not vice versa. Design The optical properties of the mirror can be tuned by changing the thickness of the reflecting layer. The glass is coated with, or has encased within, a thin and almost-transparent layer of metal (usually aluminium). The result is a mirrored surface that reflects some light and is penetrated by the rest. A true one way mirror does not, and cannot, exist. Light always passes exactly equally in both directions. Use A one-way mirror is typically used as an apparently normal mirror in a brightly lit room, with a much darker room on the other side. When such mirrors are used for one-way observation, the viewing room is kept dark by a darkened curtain or a double door vestibule. Smaller versions are sometimes used in: See also
New Studies Suggest the Speed of Light is Variable : science Mar 25, 2013 03:26 PM EDT Thus far, textbook descriptions of the speed of light assume that the light is traveling in a vacuum. Space, however, is not a vacuum. According to the Alpha Galileo Foundation, two new studies slotted for publication in the European Physical Journal D demonstrate that the speed of light is actually variable. The authors of the studies include March Urban of the University of Paris-Sud, along with Gerd Leuchs and Luis L. Sanchez-Soto from the Max Planck Institute for the Physics of Light in Erlangen, Germany. A major part of the discussion in both studies is the nature of a vacuum, which on a quantum level is not, as most believe, empty. First, Urban and his team propose that there are in fact a limited number of particle pairs including electron-positron or quark-antiquark pairs within a vacuum. In their study, Leuchs and Sanchez-Soto found that variations in the speed of light can reveal the number of charged elementary particles in any given space.
A world first! Success at complete quantum teleportation Furusawa group at the University of Tokyo has succeeded in demonstrating complete quantum teleportation of photonic quantum bits by a hybrid technique for the first time worldwide. In 1997, quantum teleportation of photonic quantum bits was achieved by a research team at Innsbruck University in Austria. However, such quantum teleportation couldn't be used for information processing, because measurement was required after transport, and the transport efficiency was low. So, quantum teleportation was still a long way from practical use in quantum communication and quantum computing. The demonstration of quantum teleportation of photonic quantum bits by Furusawa group shows that transport efficiency can be over 100 times higher than before. "In 1997, quantum bit teleportation was successfully achieved, but as I said just now, it was only achieved in a probabilistic sense. "I think we can definitely say that quantum computers have come closer to reality.
Nuclear fusion milestone passed at US lab 7 October 2013Last updated at 17:25 ET By Paul Rincon Science Editor, BBC News website The achievement is the first of its kind anywhere in the world Researchers at a US lab have passed a crucial milestone on the way to their ultimate goal of achieving self-sustaining nuclear fusion. Harnessing fusion - the process that powers the Sun - could provide an unlimited and cheap source of energy. But to be viable, fusion power plants would have to produce more energy than they consume, which has proven elusive. Now, a breakthrough by scientists at the National Ignition Facility (NIF) could boost hopes of scaling up fusion. NIF, based at Livermore in California, uses 192 beams from the world's most powerful laser to heat and compress a small pellet of hydrogen fuel to the point where nuclear fusion reactions take place. This is a step short of the lab's stated goal of "ignition", where nuclear fusion generates as much energy as the lasers supply. Continue reading the main story Nuclear fusion at NIF
Molten air – a new class of battery The molten air batteries combine useful characteristics from existing types of batteries © Shutterstock Scientists from the US have invented a new type of battery. The so-called ‘molten air batteries’ have among the highest electrical storage capacities of all battery types to date. Inexpensive batteries with better energy storage densities are needed for many applications. Stuart Licht and his group at George Washington University think their molten air batteries could be the answer. Another important advantage of molten air batteries is that, unlike some other high energy batteries, the molten air battery is rechargeable. ‘The high storage capacity of these batteries is extraordinary to observe,’ says Licht. ‘This is the first report of a rechargeable high temperature air battery,’ says Derek Fray, a molten salts expert at the University of Cambridge in the UK.