The Physics arXiv Blog
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How Hawking radiation may explain dark energy
In 1993, the Dutch Nobel prize-winning physicist Gerard t’Hooft suggested that all the information in a region of space can be represented as a hologram, an idea that implies that the laws of physics that govern our universe are somehow encoded on its (higher dimensional) boundary. This idea, known as the holographic principle, has a…
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The wound ballistics question
The gloves are off in the world of wound ballistics. The question is: how do handgun bullets do their damage? According to Martin Fackler, a retired colonel and battlefield surgeon in the US Army Medical Corp, the main cause of injury is along or close to the wound channel, the path the bullet takes through…
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In case ya missed ’em…
…the sweetmeats from this week’s physics arXiv blog: Single photons bounced off orbiting satellite Future brightens for quantum imaging New type of pulsating star discovered Do galactic cosmic rays influence global warming? Entanglement beats gravitational test
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Photons ‘n’ fermions
The best of the rest from the physics arXiv this week: An Introduction to the Dark Energy Problem Designing Potentials by Sculpturing Wires Emergent Gravity and Dark Energy Is the CMB Cold Spot a Gate to Extra Dimensions? Evacuation Dynamics: Empirical Results, Modeling and Applications Coherent Meta-materials and the Lasing Spaser Translation of Leonhard Euler’s:…
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Entanglement beats gravitational test
When does a quantum measurement end? Surprisingly, quantum physicists cannot agree. Some say the measurement ends when you register a result on a piece of classical equipment such as a photomultiplier. Others says the measurement ends when the information in the quantum system has irreversibly leaked into the environment. There are still more who believe…
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Do galactic cosmic rays influence global warming?
A vipers nest on the arXiv today from two groups covering the question of whether cosmic rays can trigger cloud formation and may therefore be a significant player in the global warming debate. The thinking goes like this: cosmic rays ionise the atmosphere, triggering the formation of aerosols which in turn nucleate cloud cover. The…
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New type of pulsating star discovered
New types of stars aren’t found very often but last year, Patrick Dufour and pals discovered several white dwarfs with carbon atmospheres. Before then white dwarfs were thought to come in two flavours: with atmopsheres dominated by either hydrogen or helium. Astronomers suddenly had a new toy to play with. Dufour found nine examples of…
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Future brightens for quantum imaging
This is the idea behind quantum imaging: create an entangled pair of photons and send one towards the object you want to image and hang on to the other. But then what? For some time, physcists have been whisperin’ about the extraordinary potential of this technique. Some imagine that it might be possible to create…
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Single photons bounced off orbiting satellite
Quantum physicists have been sending qubits through the atmosphere encoded in individual photons for years now. The work is the foundation of a new type of quantum communication that is perfectly secure from eavesdropping. But there are challenges in setting up a global system of quantum communication. Not least is the problem of decoherence, in…
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In case ya missed ’em…
…the peaches from the physics arXiv blog this week: Can data overload protect our privacy? Avoiding heat death at the end of the Universe Proof that a minority of streets handle the majority of traffic Winning and the marathon of life Are primordial quark nuggets hiding among the asteroids?