Month: March 2008
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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?
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Jewels ‘n’ nuggets
The best of the rest from the physcis arXiv: The Gravitational Bohr Radius WiFly: Experimenting with Wireless Sensor Networks and Virtual coordinates A Perfect Metamaterial Absorber Danger Theory: The Link between AIS and IDS Econophysics: Historical Perspectives Cometary Activity at 25.7 AU: Hale–Bopp 11 Years after Perihelion
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Are primordial quark nuggets hiding among the asteroids?
Jorge Horvath from the Universidade de Sao Paulo in Brazil seems to think so and believes that our current search for near Earth asteroids may uncover them. Here is his thinkin’. About 20 years ago, a number of physicists investigated the possibility that a quark gluon plasma–a state of matter that should only have existed…
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Winning and the marathon of life
Look at the finishers in a typical marathon and a simple pattern immediately emerges. After the race winner, there is a trickle of fast finishers that gradually turns into a steady flow as the finish time approaches 3 hours. The main pack arrives in the range of 3–6 hours, with a decreasing stream of progressively…
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Proof that a minority of streets handle the majority of traffic
In recent years, physicists have turned their penetrating gaze towards the structure of towns and cities. What they tend to do is measure the “connectedness” of a town by looking at how many roads each street is connected to. It turns out, that cities follow an 80/20 rule, that 80 percent of the streets have…