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H H

Quantum Random Number Generator Created Using A Smartphone Camera - 1 views

shared by H H on 19 May 14 - No Cached
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    Physicists have exploited the laws of quantum mechanics to generate random numbers on a Nokia N9 smartphone, a breakthrough that could have major implications for information security
annaheffernan

Particle accelerator barely bigger than a grain of sand - 3 views

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    Just getting a particle up to near the speed of light isn't good enough for today's physics. To properly unravel the fundamentals of the universe, particles have to be smashed together with enormous force. And two Stanford researchers have just devised a laser-based method that imparts ten times the power of traditional methods at a fraction of the cost.
annaheffernan

Physicsworld top 10 breakthroughs of the year - at the top Rosetta - 3 views

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    Physicsworld releases their top 10 breakthroughs of the year 2014, ESA's Rosetta mission tops the list with the achievement of landing on a comet.
Thijs Versloot

Properties of galaxies reproduced by hydrodynamic simulation (VIDEO) - 3 views

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    Scientists at MIT have traced 13 billion years of galaxy evolution, from shortly after the Big Bang to the present day. Their simulation, named Illustris, captures both the massive scale of the Universe and the intriguing variety of galaxies - something previous modelers have struggled to do. It produces a Universe that looks remarkably similar to what we see through our telescopes, giving us greater confidence in our understanding of the Universe, from the laws of physics to our theories about galaxy formation. "Simulation is the future of innovation"
anonymous

Nasa validates 'impossible' space drive (Wired UK) - 3 views

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    NASA validates the EmDrive (http://emdrive.com/) technology for converting electrical energy into thrust. (from the website: "Thrust is produced by the amplification of the radiation pressure of an electromagnetic wave propagated through a resonant waveguide assembly.")
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    I would be very very skeptic on this results and am actually ready to take bets that they are victims of something else than "new physics" ... some measurement error e.g.
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    Assuming that this system is feasible, and taking the results of Chinese team (Thrust of 720 mN http://www.wired.co.uk/news/archive/2013-02/06/emdrive-and-cold-fusion), I wonder whether this would allow for some actual trajectory maneuvers (and to which degree). If so, can we simulate some possible trajectories, e.g. compare the current solutions to this one ? For example, Shawyer (original author) claims that this system would be capable of stabilizing ISS without need for refueling. Other article on the same topic: http://www.theverge.com/2014/8/1/5959637/nasa-cannae-drive-tests-have-promising-results
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    To be exact, the chinese reported 720mN and the americans found ~50microN. The first one I simply do not believe and the second one seems more credible, yet it has to be said that measuring such low thrust levels on a thrust-stand is very difficult and prone to measurement errors. @Krzys, the thrust level of 720mN is within the same range of other electric propulsion systems which are considered - and even used in some cases - for station keeping, also for the ISS actually (for which there are also ideas to use a high power system delivering several Newtons of thrust). Then on the idea, I do not rule out that an interaction between the EM waves and 'vacuum' could be possible, however if this would be true then this surely would be detectable in any particle accelerator as it would produce background events/noise. The energy densities involved and the conversion to thrust via some form of interaction with the vacuum surely could not provide thrusts in the range reported by the chinese, nor the americans. The laws of momentum conservation would still need to apply. Finally, 'quantum vacuum virtual plasma'.. really?
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    I have to join the skeptics on this one ...
Thijs Versloot

Improved Saturn Positions Help Spacecraft Navigation, Planet Studies, Fundamental Physics - 0 views

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    Scientists have used the National Science Foundation's Very Long Baseline Array (VLBA) radio-telescope system and NASA's Cassini spacecraft to measure the position of Saturn and its family of moons to within about a mile -- at a range of nearly a billion miles.
jcunha

Pathological Science - 0 views

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    More in the ethic realm, I once was in a talk by Ivan Schuller (http://ischuller.ucsd.edu/) where he revisited the concept of Langmuir's Pathological Science (http://yclept.ucdavis.edu/course/280/Langmuir.pdf), defined as the act in which "people are tricked into false results ... by subjective effects, wishful thinking or threshold interactions" providing a list of aspects common to fraudulent science. Unfortunately there is no video of this very interesting talk, but the slides are available here: http://ethics.ucsd.edu/seminars/seminars/2006/summaries/Pathological_Science.pdf
LeopoldS

A way forward to solve the hard problem of consciousness - 5 views

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    enjoy ....
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    ok, but if we first have to define consciousness before starting dealing with any physics, isn't a large pause looming ahead, proposed by the author?
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    I kind of subscribe to Tononi's information theory approach to consciousness: http://www.biolbull.org/content/215/3/216.full And of course the watered down wikipedia version for whoever lacks the patience to read the whole treatise http://en.wikipedia.org/wiki/Integrated_information_theory
Thijs Versloot

Liquid metal brings shape-shifting robot a step closer - 2 views

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    Hasta la vista, baby. A real-life T-1000, the shape-shifting liquid-metal robot from Terminator 2, is a step closer, thanks to a self-powered liquid metal motor. The device is surprisingly simple: just a drop of metal alloy made mostly of gallium - which is liquid at just under 30 °C - with some indium and tin mixed in.
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    Jarvis could make it, add a power supply and aquarium and we are off :)
Thijs Versloot

Watch uranium radiation inside a cloud chamber - 6 views

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    Ever wondered what radiation looks like? If you have, I bet you didn't think it would look as cool as this. This is a small piece of uranium mineral sitting in a cloud chamber, which means you can see the process of decay and radiation emission....
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    Once I saw a DIY spark chamber in LIP (CERN associated laboratory). It was the work of a bunch of BSc students, they made it all from scratch, so it seemed to be not that difficult to have one at home. Yet another project for the future 'Experimental Physics' stagiare maybe :)
annaheffernan

Plasmons excite hot carriers - 1 views

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    The first complete theory of how plasmons produce "hot carriers" has been developed by researchers in the US. The new model could help make this process of producing carriers more efficient, which would be good news for enhancing solar-energy conversion in photovoltaic devices.
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    I did not read the paper but what is further down written in the article, does not give much hope that this actually gives much more insight than what we had nor that it could be used in any way to improve current PV cells soon: e.g. "To fully exploit these carriers for such applications, researchers need to understand the physical processes behind plasmon-induced hot-carrier generation. Nordlander's team has now developed a simple model that describes how plasmons produce hot carriers in spherical silver nanoparticles and nanoshells. The model describes the conduction electrons in the metal as free particles and then analyses how plasmons excite hot carriers using Fermi's golden rule - a way to calculate how a quantum system transitions from one state into another following a perturbation. The model allows the researchers to calculate how many hot carriers are produced as a function of the light frequency used to excite the metal, as well as the rate at which they are produced. The spectral profile obtained is, to all intents and purposes, the "plasmonic spectrum" of the material. Particle size and hot-carrier lifetimes "Our analyses reveal that particle size and hot-carrier lifetimes are central for determining both the production rate and the energies of the hot carriers," says Nordlander. "Larger particles and shorter lifetimes produce more carriers with lower energies and smaller particles produce fewer carriers, but with higher energies."
Thijs Versloot

The Reality of Quantum Mechanics @WIRED - 3 views

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    "Quantum mechanics is very successful; nobody's claiming that it's wrong," said Paul Milewski, a professor of mathematics at the University of Bath in England who has devised computer models of bouncing-droplet dynamics. "What we believe is that there may be, in fact, some more fundamental reason why [quantum mechanics] looks the way it does."
Christophe Praz

Brain decoder can eavesdrop on your inner voice - 4 views

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    "As you read this, your neurons are firing - that brain activity can now be decoded to reveal the silent words in your head TALKING to yourself used to be a strictly private pastime. That's no longer the case - researchers have eavesdropped on our internal monologue for the first time. The achievement is a step towards helping people who cannot physically speak communicate with the outside world." Or alternatively, a step towards snooping into individuals' privacy.
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    Soon we'll be able to see movies about our dreams!
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    Only if you are willing to have a chip implanted into/onto your brain though ^^
Athanasia Nikolaou

NASA Vesta Trek - 2 views

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    NASA Releases Tool Enabling Citizen Scientists to Examine Asteroid Vesta Vesta Trek is a free, web-based application that provides detailed visualizations of Vesta, one of the largest asteroids in our solar system. NASA's Dawn spacecraft studied Vesta from July 2011 to September 2012. Data gathered from multiple instruments aboard Dawn have been compiled into Vesta Trek's user-friendly set of tools, enabling citizen scientists and students to study the asteroid's features. The application includes: -- Interactive maps with the ability to overlay a growing range of data sets including topography, mineralogy, abundance of elements and geology, as well as analysis tools for measuring the diameters, heights and depths of surface features and more. -- 3-D printer-exportable topography so users can print physical models of Vesta's surface. -- Standard keyboard gaming controls to manoever a first-person visualization of "flying" across the surface of the asteroid. "There's nothing like seeing something with your own eyes, but these types of detailed data-visualizations are the next best thing," said Kristen Erickson, Director, Science Engagement and Partnerships at NASA Headquarters in Washington DC.
jcunha

Kilogram conflict resolved at last - 3 views

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    Apparently it's time for retirement of the Le Grand K, if all goes well until the middle of next year...
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    "One method (...) involves counting the atoms in two silicon-28 spheres that each weigh the same as the reference kilogram." Sounds like a lengthy task, but someone must keep those physics PhD students busy, I guess...
jcunha

Computer model matches humans at predicting how objects move - 0 views

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    We humans take for granted our remarkable ability to predict things that happen around us. Here, a deep learning model trained from real-world videos and a 3D graphics engine was able to infer physical properties of objects against humans.
LeopoldS

Phys. Rev. D 93, 024014 (2016) - How current loops and solenoids curve spacetime - 1 views

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    modifying gravity? Jai?
joergmueller

In a new round of testing, NASA confirms yet again that the 'impossible' EMdrive thrust... - 4 views

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    Engineer Roger Shawyer's controversial EM Drive thruster jets back into relevancy this week, as a team of researchers at NASA's Eagleworks Laboratories recently completed yet another round of testing on the seemingly impossible tech.
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    I like this just because it will end up on Thijs' desk :D
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    Interesting that the new comes in... Yahoo Finance :). Another more complete article http://nextbigfuture.com/2015/11/nasa-eagleworks-has-tested-upgraded.html
LeopoldS

Undecidability of the spectral gap : Nature : Nature Publishing Group - 3 views

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    if anybody was still doubting: Gödel was a real genius!
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