Skip to main content

Home/ Advanced Concepts Team/ Group items tagged phy

Rss Feed Group items tagged

Paul N

Gravitational wave discovery kills 90% of physics theories - 0 views

  •  
    "The BICEP2 data would eliminate about 90% of inflationary models, Andrei Linde, a cosmologist at Stanford University in California, told a packed auditorium at MIT the day after the BICEP2 announcement (see picture below). Many of those models do not produce gravitational waves at detectable levels, said Linde, who is one of the founders of inflation theory."

    Is there any hope for LISA now?
  •  
    Of course - the data is more proof that GWs exist!!
  •  
    so you don't expect any impact on the science objectives of Lisa at all?
Ma Ru

Here come gravitational waves - 3 views

  •  
    Here you go. You can now scrap Lisa altogether.
    Who's going to tell Pacome?
  •  
    Awesome and exciting stuff indeed!

    The data pinpoint the time when inflation occurred - about 10E-37 seconds into the Universe's life - and its temperature at the time, corresponding to energies of about 10E16 gigaelectronvolts, says cosmologist Michael Turner of the University of Chicago. That is the same energy at which three of the four fundamental forces of nature - the weak, strong and electromagnetic force - are expected to become indistinguishable from one another in a model known as the grand unified theory.

    I expect more fundamental physics insights to come out of this in the future. A full-sky survey from space may still be an interesting addition to the measurement capabilities, so I would not rule out LISA all together I guess...
Marcus Maertens

World First: 3D Acoustic Cloaking Device | I Fucking Love Science - 1 views

  •  
    Old news... Sante was doing this 10 years ago! And why does their metamaterial look like a pyramid?
  •  
    According to Terry Pratchett pyramids affect the flow of time. Using this, any kind of cloaking device should be trivial.
Tom Gheysens

Did dark matter kill the dinosaurs? : Nature News & Comment - 1 views

  •  
    theoretical physicists... :)

    Read the last sentence of the paper...in this way anyone can publish in nature...just make a good story with little evidence

    Did dark matter kill the dinosaurs?
    The Solar System's periodic passage through a 'dark disk' on the galactic plane could trigger comet bombardments that would cause mass extinctions.
  •  
    Hmm.. right.. then again, this is not an actual journal publication but a news broadcast. But you are right that the name Nature is attached to it so the journal is definitely banking on their acquired status.
Tom Gheysens

First step towards 'programmable materials': Sheet metal that never rattles -- ScienceD... - 2 views

  •  
    Very nice new concept for active vibration damping.
    I think this has huge potential for space applications
Marcus Maertens

Supernova Core Imaged For the First Time - 0 views

  •  
    towards a better understanding about the fusion processes in the last moments of a star's life.
Marcus Maertens

Stephen Hawking: 'There are no black holes' : Nature News & Comment - 1 views

  •  
    Event Horizon - a modern myth?
  •  
    GR is valid on large scales and is, therefore, a simplification of the unknown GUT. As such, the mathematical solutions obtained in GR are strictly speaking valid only within GR. Certainly, the solution called black hole is an extremely heavy object and at the same time extremely small - a point without geometrical extension. The latter is heavily in conflict with the validity range of the underlying theory and, hence, makes lots of people (including experts unlike me) question the concept of black holes despite the fact that something has been "observed" which fits into this concept.

    Regarding the movie: Event Horizon might be a myth but it emphasizes what Sante said in on of his presentations: Don't use a black hole for travelling, take the worm hole instead. The constructor of Event Horizon created a black hole not considering that the damn thing has no exit...where did he think the Event Horizon would end?
Marcus Maertens

Physicists create synthetic magnetic monopole predicted more than 80 years ago - 1 views

  •  
    Hall's team adopted an innovative approach to investigating Dirac's theory, creating and identifying synthetic magnetic monopoles in an artificial magnetic field generated by a Bose-Einstein condensate, an extremely cold atomic gas tens of billionths of a degree warmer than absolute zero.
Ma Ru

Information Preservation and Weather Forecasting for Black Holes - 2 views

  •  
    S. Hawking argues black holes might not exist: "The absence of event horizons mean that there are no black holes - in the sense of regimes from which light can't escape to infinity."
    Physicists will likely appreciate...
Tom Gheysens

Analysis of salamander jump reveals an unexpected twist - 1 views

  •  
    here is the video - did not really get the mechanism
Beniamino Abis

Antimatter experiment produces first beam of antihydrogen - 1 views

  •  
    The ASACUSA experiment at CERN has succeeded for the first time in producing a beam of antihydrogen atoms. The ASACUSA collaboration reports the unambiguous detection of 80 antihydrogen atoms 2.7 metres downstream of their production, where the perturbing influence of the magnetic fields used initially to produce the antiatoms is small.
    http://www.nature.com/ncomms/2014/140121/ncomms4089/full/ncomms4089.html
dejanpetkow

Photonic calculus with analog computer - 5 views

  •  
    Weird.
  •  
    This reminds me a 2013 paper on how to perform derivatives, integrals and even time reversal in optical fibres:

    http://www.nature.com/srep/2013/130403/srep01594/full/srep01594.html

    "The manipulation of dynamic Brillouin gratings in optical fibers is demonstrated to be an extremely flexible technique to achieve, with a single experimental setup, several all-optical signal processing functions. In particular, all-optical time differentiation, time integration and true time reversal are theoretically predicted, and then numerically and experimentally demonstrated."
  •  
    Would this kind of computer be more space environment resistive?
dejanpetkow

Metamaterials + Wireless Power Transfer - 2 views

  •  
    Put together two ACT topics and see what happens.
  •  
    I remember discussing this briefly and then discarding the idea - but don't remember why any more; duncan?
  •  
    Well, I think that although the antenna is small, you counteract this with a much large metameterial lens. Probably if you design an antenna of a similar size to the 'lens' you can couple power equally well over the same distance. Then again, further optimization might help improve the size. Maybe in the end you want to combine both together, optimization of the antenna, including a metamaterials lens.
Tom Gheysens

Cheap battery stores energy for a rainy day : Nature News & Comment - 0 views

  •  
    Thijs interested?

    quinones are my field
  •  
    I think the major benefit of this system is the low cost of the products involved compared to standard flow batteries. However, two issues still remain, corrosion and size. I think these things need to be big right due to the volumetric storage using quinones? Nevertheless, it is interesting to see where this development will lead to.

    "The system is far from perfect, however: bromine and hydrobromic acid are corrosive, and could cause serious pollution if they leaked. "The bromine is, right now, the Achilles heel of this particular battery," Aziz says. The answer could be to go completely organic, he adds: "We are working on replacing the bromine with a different quinone."

    Are there quinones which would not be corrosive but retain good volumetric performance?
Tom Gheysens

Biomimicr-E: Nature-Inspired Energy Systems | AAAS - 4 views

  •  
    some biomimicry used in energy systems...
    maybe it sparks some ideas
  •  
    not much new that has not been shared here before ... BUT: we have done relativley little on any of them. for good reasons?? don't know - maybe time to look into some of these again more closely

    Energy Efficiency(

    Termite mounds inspired regulated airflow for temperature control of large structures, preventing wasteful air conditioning and saving 10% energy.[1]
    Whale fins shapes informed the design of new-age wind turbine blades, with bumps/tubercles reducing drag by 30% and boosting power by 20%.[2][3][4]
    Stingray motion has motivated studies on this type of low-effort flapping glide, which takes advantage of the leading edge vortex, for new-age underwater robots and submarines.[5][6]
    Studies of microstructures found on shark skin that decrease drag and prevent accumulation of algae, barnacles, and mussels attached to their body have led to "anti-biofouling" technologies meant to address the 15% of marine vessel fuel use due to drag.[7][8][9][10]
    Energy Generation(

    Passive heliotropism exhibited by sunflowers has inspired research on a liquid crystalline elastomer and carbon nanotube system that improves the efficiency of solar panels by 10%, without using GPS and active repositioning panels to track the sun.[11][12][13]
    Mimicking the fluid dynamics principles utilized by schools of fish could help to optimize the arrangement of individual wind turbines in wind farms.[14]
    The nanoscale anti-reflection structures found on certain butterfly wings has led to a model to effectively harness solar energy.[15][16][17]
    Energy Storage(

    Inspired by the sunlight-to-energy conversion in plants, researchers are utilizing a protein in spinach to create a sort of photovoltaic cell that generates hydrogen from water (i.e. hydrogen fuel cell).[18][19]
    Utilizing a property of genetically-engineered viruses, specifically their ability to recognize and bind to certain materials (carbon nanotubes in this case), researchers have developed virus-based "scaffolds" that
Paul N

Three-Dimensional Mid-Air Acoustic Manipulation - 0 views

  •  
    Turns out you can do stuff with sound if you have enough of it.
Tom Gheysens

Electron 'antenna' tunes in to physics beyond Higgs - 0 views

  •  
    Anna, Sante, some Christmas reading!

    Real theoretical physicists never sleep ;)

LeopoldS

Peter Higgs: I wouldn't be productive enough for today's academic system | Science | Th... - 1 views

  •  
    what an interesting personality ... very symathetic

    Peter Higgs, the British physicist who gave his name to the Higgs boson, believes no university would employ him in today's academic system because he would not be considered "productive" enough.

    The emeritus professor at Edinburgh University, who says he has never sent an email, browsed the internet or even made a mobile phone call, published fewer than 10 papers after his groundbreaking work, which identified the mechanism by which subatomic material acquires mass, was published in 1964.

    He doubts a similar breakthrough could be achieved in today's academic culture, because of the expectations on academics to collaborate and keep churning out papers. He said: "It's difficult to imagine how I would ever have enough peace and quiet in the present sort of climate to do what I did in 1964."

    Speaking to the Guardian en route to Stockholm to receive the 2013 Nobel prize for science, Higgs, 84, said he would almost certainly have been sacked had he not been nominated for the Nobel in 1980.

    Edinburgh University's authorities then took the view, he later learned, that he "might get a Nobel prize - and if he doesn't we can always get rid of him".

    Higgs said he became "an embarrassment to the department when they did research assessment exercises". A message would go around the department saying: "Please give a list of your recent publications." Higgs said: "I would send back a statement: 'None.' "

    By the time he retired in 1996, he was uncomfortable with the new academic culture. "After I retired it was quite a long time before I went back to my department. I thought I was well out of it. It wasn't my way of doing things any more. Today I wouldn't get an academic job. It's as simple as that. I don't think I would be regarded as productive enough."

    Higgs revealed that his career had also been jeopardised by his disagreements in the 1960s and 7
  •  
  •  
    interesting one - Luzi will like it :-)
jmlloren

Why starting from differential equations for computational physics? - 1 views

  •  
    "The computational methods currently used in physics are based on the discretization of differential equations. This is because the computer can only perform algebraic operations. The purpose of this paper is to critically review this practice, showing how to obtain a purely algebraic formulation of physical laws starting directly from experimental measurements."
pandomilla

Flexible, stretchable fire-ant rafts - 2 views

  •  
    An ant raft stays on top of the water surface even when it is hardly pressed by a branch -- showing water repellency and buoyancy. What do Jell-O, toothpaste, and floating fire-ant rafts have in common?
  • ...1 more comment...
  •  
    wow!! cool experiments ..... I had no idea
  •  
    It's a strategy the ants actually actively exploit in the wild:
    http://www.youtube.com/watch?v=A042J0IDQK4
    http://www.youtube.com/watch?v=r04kAnzgjR4
  •  
    somebody showed such videos some years ago in one of our talks on swarm cooperation ... probably Tobias? or P. Dario? ... still impressive indeed
1 - 20 of 514 Next › Last »
Showing 20 items per page