Posts tagged "physics"

• Graphene Combined with Quantum Dots Result in Efficient Photodetector →

  

  Graphene research has been turning increasingly towards its potential in optoelectronic applications. This is not a surprise because graphene’s optical properties are as astounding its electrical conductivity capabilities.

  But just as graphene has the glaring Achilles Heel in electronics applications of lacking a band gap, it also suffers a couple of fatal flaws in optoelectronics. For example, while nearly every single photon the material absorbs generates an electron-hole pair, it doesn’t really absorb that much light. According to some estimates, it absorbs less than 3 percent of the photons falling on it.

  graphene quantum physics research future
  1 week ago reblog like 2 notes
• New technique uses electrons to map nanoparticle atomic structures →

  With dimensions measuring billionths of a meter, nanoparticles are way too small to see with the naked eye. Yet it is becoming possible for today’s scientists not only to see them, but also to look inside at how the atoms are arranged in three dimensions using a technique called nanocrystallography. Trouble is, the powerful machines that make this possible, such as x-ray synchrotrons, are only available at a handful of facilities around the world. The U.S. Department of Energy’s Brookhaven National Laboratory is one of them — home to the National Synchrotron Light Source (NSLS) and future NSLS-II, where scientists are using very bright, intense x-ray beams to explore the small-scale structure of new materials for energy applications, medicine, and more.

  But a Brookhaven/Columbia Engineering School team of scientists, in collaboration with researchers at DOE’s Argonne National Laboratory (ANL) and Northwestern University, has also been working to develop nanocrystallography techniques that can be used in more ordinary science settings. They have shown how a powerful method called atomic pair distribution function (PDF) analysis — which normally requires synchrotron x-rays or neutrons to discern the atomic arrangements in nanoparticles — can be carried out using a transmission electron microscope (TEM) — an instrument found in many chemistry and materials science laboratories.

  nanotech atomic research physics
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• No-fuss device delivers entangled photons →

  

  A new device could move supercomputing out of the lab by making it faster and easier to produce a special class of photons.

  physics photons atomic research
  3 weeks ago reblog like 5 notes
• An analog quantum computer made of cold atoms used to simulate electrons' spins →

  

  Many of the most exciting properties of materials arise due to interactions between electrons. Correlations between electrons’ spins are involved in magnetism and may be responsible for high-temperature superconductivity—yet it’s tough to get theory to match our experimental results. The major reason for the difficulty lies in how quickly they scale: the more interactions between spins, the more difficult it is to calculate their effects. As few as 30 interacting spins reaches the limits of modern computers.

  atomic quantum computers future research physics
  3 weeks ago reblog like 5 notes
• Optical trap catches atoms swinging in time to theory →

  

  It’s bizarre to feel awestruck and disappointed at the same time. Yet this is often how I feel when I read articles about ultracold atoms and Bose Einstein condensates. I’ll get to the awesome and awestruck parts later, but let me explain my disappointment. These experiments sit right at the boundary between classical and quantum physics. When we play with ultracold atoms, we make macroscopic objects do quantum things. And what have we discovered? That quantum mechanics is pretty much correct.

  atomic research physics
  3 weeks ago reblog like 7 notes
• Raising the prospects for quantum levitation →

  An eerie quantum force may one day help separate the surfaces in tiny machines for frictionless movement. More than half-a-century ago, the Dutch theoretical physicist Hendrik Casimir calculated that two mirrors placed facing each other in a vacuum would attract. The mysterious force arises from the energy of virtual particles flitting into and out of existence, as described by quantum theory. Now Norio Inui, a scientist from the University of Hyogo in Japan, has predicted that in certain circumstances a reversal in the direction of the so-called Casimir force would be enough to levitate an extremely thin plate.

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• What Happens Inside the Large Hadron Collider?

  physics CERN research video videos
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• Path Clears Toward a Quantum Internet →

  

  In the quest to build networks that can carry information reliably and with absolute security over long distances, scientists are now a big step closer, according to research in this week’s issue of Nature.

  Stephan Ritter and his colleagues at the Max Planck Institute of Quantum Optics, in Garching, Germany, have constructed an elementary quantum network with two nodes. They say it is a proof of concept that could one day be extended to create large-scale quantum information networks that guarantee the security of message transmission by encoding data using the quantum state of photons.

  quantum Internet future research physics
  1 month ago reblog like 9 notes
• A quantum network built with two atoms and fiber optic cable →

  

  In an ordinary computer network, data in the form of binary numbers are transferred from one machine (node) to another via some sort of electronic signal, either electrical or optical. The success of this transfer comes when the recipient has precisely the same set of binary figures that were sent. In a quantum network, the “data” is a quantum state—the particular configuration of an atom’s energy, spin, etc.—and the transfer of information is successful if the state is reproduced in a separate quantum system some distance away.

  quantum computers future research physics networks
  1 month ago reblog like 8 notes
• Researchers find a way to keep quantum memory and logic in synch →

  

  A quantum computer, like any other computer, requires a way to store and retrieve information. In other words, some sort of memory. But because of the rich quantum entanglement gooey center of quantum computing, the memory and the logic need to be linked in a manner that’s very different from that in classical computing: the magic of entanglement.

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• Quantum information motion control is now improved →

  Physicists have recently devised a new method for handling the effect of the interplay between vibrations and electrons on electronic transport. Their paper is about to be published in The European Physical Journal B. This study, led by scientists from Zhejiang University, Hangzhou, China, and the Centre for Computational Science and Engineering at the National University of Singapore, could have implications for quantum computers due to improvements in the transport of discrete amounts of information, known as qubits, that are encoded in electrons.

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• Ultracold experiments heat up quantum research →

  

  University of Chicago physicists have experimentally demonstrated, for the first time, that atoms chilled to temperatures near absolute zero may behave like seemingly unrelated natural systems of vastly different scales, offering potential insights into links between the atomic realm and deep questions of cosmology.

  This ultracold state, called “quantum criticality,” hints at similarities between such diverse phenomena as the gravitational dynamics of black holes or the exotic conditions that prevailed at the birth of the universe, said Cheng Chin, associate professor in physics at UChicago. The results could even point to ways of simulating cosmological phenomena of the early universe by studying systems of atoms in states of quantum criticality.

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  2 months ago reblog like 8 notes
• For designer molecules, trick the electrons →

  

  Scientists have created the first-ever system of “designer electrons”—exotic variants of ordinary electrons with tunable properties.

  electrons physics molecules future graphene
  2 months ago reblog like 3 notes
• Scientists discover a surprising new way that protons can move among molecules →

  

  When a proton – the bare nucleus of a hydrogen atom – transfers from one molecule to another, or moves within a molecule, the result is a hydrogen bond, in which the proton and another atom like nitrogen or oxygen share electrons. Conventional wisdom has it that proton transfers can only happen using hydrogen bonds as conduits, “proton wires” of hydrogen-bonded networks that can connect and reconnect to alter molecular properties.

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• Looking at quantum gravity in a mirror →

  

  Einstein’s theory of gravity and quantum physics are expected to merge at the Planck-scale of extremely high energies and on very short distances. At this scale, new phenomena could arise. However, the Planck-scale is so remote from current experimental capabilities that tests of quantum gravity are widely believed to be nearly impossible. Now an international collaboration between the groups of Caslav Brukner and Markus Aspelmeyer at the University of Vienna and Myungshik Kim at Imperial College London has proposed a new quantum experiment using Planck-mass mirrors. Such an experiment could test certain predictions made by quantum gravity proposals in the laboratory. The findings will be published this week in Nature Physics.

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