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Mars Base

Frenchman, American win Nobel for quantum physics (Update 6) - 0 views

phys.org/...eland-nobel-physics-prize.html

scibyte67 Nobel

shared by Mars Base on 13 Oct 12 - No Cached
  • American physicist David Wineland
  • and French physicist Serge Haroche speaks to the media in Paris after they were named winners of the 2012 Nobel Prize in physics.
  • for experiments on quantum particles that have already resulted in ultra-precise clocks and may one day help lead to computers many times faster than those in use today.
  • ...7 more annotations...
  • A Frenchman and an American shared the Nobel Prize in physics Tuesday for inventing methods to peer into the bizarre quantum world of ultra-tiny particles, work that could help in creating a new generation of super-fast computers
  • quantum computers could radically change people's lives in the way that classical computers did last century, but a full-scale quantum computer is still decades away
  • in a quantum computer, an individual particle can essentially represent a zero and a one at the same time
  • If scientists can make such particles work together, certain kinds of calculations could be done with blazing speed.
  • The prizes are always handed out on Dec. 10, the anniversary of prize founder Alfred Nobel's death in 1896.
  • 2012: Serge Haroche of France and David Wineland of the U.S. for "for ground-breaking experimental methods" that enable measuring and manipulation of individual quantum systems
  • 2011: American physicist Saul Perlmutter, U.S.-Australian researcher Brian Schmidt and American professor Adam Riess "for the discovery of the accelerating expansion of the Universe through observations of distant supernovae."
Mars Base

Alan Guth on new insights into the 'Big Bang' - 0 views

phys.org/...03-alan-guth-insights-big.html

scibyte124 Inflation

shared by Mars Base on 22 Mar 14 - No Cached
  • Q: Can you explain the theory of cosmic inflation that you first put forth in 1980?
  • usually describe inflation as a theory of the "bang" of the Big Bang
  • describes the propulsion mechanism that drove the universe into the period of tremendous expansion that we call the Big Bang
  • ...49 more annotations...
  • The original Big Bang theory was really a theory of the aftermath of the bang
  • described how the universe was cooled by the expansion, and how the expansion was slowed by the attractive force of gravity
  • Inflation proposes that the expansion of the universe was driven by a repulsive form of gravity.
  • According to Newton, gravity is a purely attractive force, but this changed with Einstein and the discovery of general relativity
  • General relativity describes gravity as a distortion of spacetime, and allows for the possibility of repulsive gravity
  • Modern particle theories strongly suggest that at very high energies, there should exist forms of matter that create repulsive gravity
  • Inflation
  • proposes that at least a very small patch of the early universe was filled with this repulsive-gravity material
  • During the period of exponential expansion, any ordinary material would thin out, with the density diminishing to almost nothing
  • The repulsive-gravity material actually maintains a constant density as it expands, no matter how much it expands
  • While this appears to be a
  • violation
  • of the conservation of energy, it is actually
  • consistent
  • a peculiar feature of gravity: The energy of a gravitational field is negative
  • As the patch expands at constant density, more and more energy, in the form of matter, is created
  • But at the same time, more and more negative energy appears in the form of the gravitational field that is filling the region
  • The total energy remains constant, as it must, and therefore remains very small.
  • It is possible that the total energy of the entire universe is exactly zero, with the positive energy of matter completely canceled by the negative energy of gravity
  • At some point the inflation ends because the repulsive-gravity material becomes metastable
  • decays into ordinary particles, producing a very hot soup of particles that form the starting point of the conventional Big Bang
  • point the repulsive gravity turns off, but the region continues to expand in a coasting pattern for billions of years to come
  • inflation is a prequel to the era that cosmologists call the Big Bang, although it of course occurred after the origin of the universe, which is often also called the Big Bang.
  • Q: What is the new result announced this week, and how does it provide critical support for your theory?
  • The early universe, as we can see from the afterglow of the cosmic microwave background (CMB) radiation, was incredibly uniform,
  • to have structure form at all, there needed to be small nonuniformities at the end of inflation
  • The tiny nonuniformities that did exist were then amplified by gravity
  • these nonuniformities—which later produce stars, galaxies, and all the structure of the universe—are attributed to quantum theory
  • The temperature nonuniformities in the cosmic microwave background were first measured in 1992 by the COBE satellite
  • have not generally been seen as proof of inflation, in part because it is not clear that inflation is the only possible way that these fluctuations could have been produced.
  • The stretching effect of inflation,
  • also acts on the geometry of space itself, which according to general relativity is flexible
  • Space can be compressed, stretched, or even twisted.
  • The geometry of space also fluctuates on small scales, due to the physics of quantum theory, and inflation also stretches these fluctuations, producing gravity waves in the early universe.
  • The new result,
  • is a measurement of these gravity waves, at a very high level of confidence.
  • They do not see the gravity waves directly, but instead they have constructed a very detailed map of the polarization of the CMB in a patch of the sky.
  • They have observed a swirling pattern in the polarization (called "B modes") that can be created
  • by gravity waves in the early universe
  • This is the first time that even a hint of these primordial gravity waves has been detected
  • it is also the first time that any quantum properties of gravity have been directly observed.
  • Q: How would you describe the significance of these new findings, and your reaction to them?
  • The significance of these new findings
  • help tremendously in confirming the picture of inflation.
  • As far as we know, there is nothing other than inflation that can produce these gravity waves
  • it tells us a lot about the details of inflation that we did not already know
  • it determines the energy density of the universe at the time of inflation, which is something that previously had a wide range of possibilities.
  • By determining the energy density of the universe at the time of inflation, the new result also tells us a lot about which detailed versions of inflation are still viable, and which are no longer viable
  • The current result is not by itself conclusive, but it points in the direction of the very simplest inflationary models that can be constructed.
Mars Base

After Higgs Boson, scientists prepare for next quantum leap - 0 views

phys.org/...-boson-scientists-quantum.html

scibyte82 HiggsBoson

shared by Mars Base on 16 Feb 13 - No Cached
  • Seven months after its scientists made a landmark discovery that may explain the mysteries of mass, Europe's top physics lab will take a break from smashing invisible particles to recharge for the next leap
  • From Thursday, the cutting-edge facilities at the European Organisation for Nuclear Research (CERN) will begin winding down, then go offline on Saturday for an 18-month upgrade
  • scientists said they were 99.9 percent certain they had found the elusive Higgs Boson,
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  • The upgrade will boost the LHC's energy capacity, essential for CERN to confirm definitively that its boson is the Higgs, and allow it to probe new dimensions such as supersymmetry and dark matter
  • We need to increase the energy to look at more physics.
  • Over the past three years, CERN has slammed protons together more than six million billion times
  • espite the shutdown, CERN's researchers won't be taking a breather, as they must trawl through a vast mound of data
  • think a year from now, we'll have more information on the data accumulated over the past three years
  • Last year, the LHC achieved a collision energy level of eight teraelectron volts, an energy measure used in particle physics—up from seven in 2011
  • After it comes back online in 2015, the goal is to take that level to 13 or even 14, with the LHC expected to run for three or four years before another shutdown.
Mars Base

Physicists create synthetic magnetic monopole predicted more than 80 years ago - 0 views

phys.org/...c-magnetic-monopole-years.html

scibyte118

shared by Mars Base on 30 Jan 14 - No Cached
  • Nearly 85 years
  • physicist
  • predicted the possibility
  • ...20 more annotations...
  • identified and photographed synthetic magnetic monopoles
  • The groundbreaking accomplishment paves the way for the detection of the particles in nature
  • "The creation of a synthetic magnetic monopole should provide us with unprecedented insight into aspects of the natural magnetic monopole—if indeed it exists,"
  • To be able to confirm the work of one of the most famous physicists is probably a once-in-a-lifetime opportunity
  • Ordinarily, magnetic poles come in pairs: they have both a north pole and a south pole
  • a magnetic monopole is a magnetic particle possessing only a single, isolated pole—a north pole without a south pole, or vice versa
  • . In 1931,
  • published a paper that explored the nature of these monopoles in the context of quantum mechanics
  • Despite extensive experimental searches since then, in everything from lunar samples—moon rock—to ancient fossilized minerals, no observation of a naturally-occurring magnetic monopole has yet been confirmed
  • team adopted an innovative approach to investigating
  • theory, creating and identifying synthetic magnetic monopoles
  • 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.
  • The team relied upon theoretical work
  • that suggested a particular sequence of changing external magnetic fields could lead to the creation of the synthetic monopole
  • Their experiments subsequently took place in the atomic refrigerator built
  • in his basement laboratory in the Merrill Science Center
  • After resolving many technical challenges, the team was rewarded with photographs that confirmed the monopoles' presence at the ends of tiny quantum whirlpools within the ultracold gas.
  • The result proves experimentally that
  • structures do exist in nature
  • Physics Professor David S. Hall '91 and Aalto University (Finland)
Mars Base

NASA - 2013 Astronaut Class - 0 views

www.nasa.gov/...2013astroclass.html

scibyte98 astronaut

shared by Mars Base on 17 Jun 13 - No Cached
  • The 2013 astronaut candidate class comes from the second largest number of applications NASA ever has received -- more than 6,100
  • Josh A. Cassada, Ph. D
  • a former naval aviator
  • ...22 more annotations...
  • is a physicist by training and currently is serving as co-founder and Chief Technology Officer for Quantum Opus
  • Victor J. Glover
  • is an F/A-18 pilot and graduate of the U.S. Air Force Test Pilot School
  • currently is serving as a Navy Legislative Fellow in the U.S. Congress
  • Tyler N. Hague
  • currently is supporting the Department of Defense as Deputy Chief of the Joint Improvised Explosive Device Defeat Organization
  • Christina M. Hammock
  • currently is serving as National Oceanic and Atmospheric Administration (NOAA) Station Chief in American Samoa
  • Nicole Aunapu Mann
  • Lt. Colonel, U.S. Air Force
  • Lt. Commander, U.S. Navy
  • Major, U.S. Marine Corps
  • is an F/A 18 pilot, currently serving as an Integrated Product Team Lead at the U.S. Naval Air Station, Patuxent River
  • Anne C. McClain
  • Major, U.S. Army
  • is an OH-58 helicopter pilot, and a recent graduate of U.S. Naval Test Pilot School at Naval Air Station, Patuxent River
  • currently is an Assistant Professor of Anesthesia at Harvard Medical School, Massachusetts General Hospital, Boston
  • Andrew R. Morgan, M.D
  • Jessica U. Meir, Ph.D.
  • Major, U.S. Army
  • has experience as an emergency physician and flight surgeon for the Army special operations community, and currently is completing a sports medicine fellowship
  • The new astronaut candidates will begin training at NASA's Johnson Space Center in Houston in August
Mars Base

The Solar Cell That Turns 1 Photon into 2 Electrons: Scientific American - 0 views

www.scientificamerican.com/article.cfm

scibyte91 solarcell

shared by Mars Base on 19 Apr 13 - No Cached
  • If an incoming photon has too little energy, the cell won’t absorb it
  • Solar cells
  • If a photon has too much, the excess is wasted as heat
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  • a silicon solar cell can never generate more than one electron from a single photon
  • severely limit the conversion efficiency of photovoltaic cells, and scientists have spent decades looking for work-arounds
  • the key to greater solar efficiency might be an organic dye called pentacene
  • a photovoltaic cell based on pentacene can generate two electrons from a single photon—more electricity from the same amount of sun.
  • The key is a phenomenon called singlet-exciton fission, in which an arriving photon generates two “excitons” (excited states) that can be made to yield two electrons.
  • Previous researchers had accomplished similar tricks using quantum dots (tiny pieces of matter that behave like atoms) and deep-ultraviolet light
  • Why it works is still not particularly clear, and for now, the pentacene cell works only with an extremely narrow band of visible light
  • it should be possible to create a pentacene coating for silicon solar cells that boosts the total conversion efficiency from today’s 25 percent to a shade over 30 percent—a significant jump
Mars Base

Quantum Diaries - 0 views

www.quantumdiaries.org/...he-way-towards-new-discoveries

scibyte53 HiggsBoson

shared by Mars Base on 06 Jul 12 - No Cached
  • All theorists today agree that our current theoretical model has its limits
  • the Standard Model
  • has more than 100 free parameters, making it impossible to obtain predictions without assigning fixed values to some of these parameters
Mars Base

Researchers at Harvard University and MIT discover previously unobserved state of matte... - 0 views

www.ctvnews.ca/...real-life-lightsaber-1.1473318

scibyte104 ViewerFeedback

shared by Mars Base on 27 Sep 13 - No Cached
  • The discovery
  • goes against what scientists previously understood of photons: that elementary light particles are massless loners that do not interact with each other.
  • Most of the properties of light we know about originate from the fact that photons are massless, and that they do not interact with each other
  • ...12 more annotations...
  • researchers fired a couple of photons into a cloud of rubidium – a chemical element belonging to the metal group – in a vacuum chamber cooled to just a few degrees above absolute zero.
  • When the photons exited the other side of the cloud of atoms
  • were surprised to see the pair emerge as a single molecule.
  • special type of medium in which photons interact with each other
  • so strongly that they begin to act as though they have mass, and they bind together to form molecules
  • Rydberg blockade
  • states that when an atom has energy imparted to it, nearby atoms cannot be excited to the same degree
  • the pair of photons moved through the cloud of atoms, the first photon excited atoms, but had to move forward before the second photon could do the same.
  • the pair of photons pushed and pulled each other through the cloud
  • atomic interaction
  • makes these two photons behave like a molecule
  • team is hoping to use their newly discovered state of matter in the advancement of quantum computing
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