Category: Weird ‘n’ spooky
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Interference between photons that never meet
The pantheon of impossible photon tricks grows ever larger. Today, a new addition from Andrew Shields and pals at Toshiba Research Europe in Cambridge, UK: “We report an experiment in which two-photon interference occurs between degenerate single photons that never meet. The two photons travel in opposite directions through our fibre-optic interferometer and interference occurs…
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A survey of quantum programming languages
It cannot be long before somebody breathes life into a useful quantum computer. And when that happens, an entirely new breed of keyboard monkey will be born: the quantum computer programmer. This strange animal will have to work with the weird and wonderful tools of the quantum world, such as superposition of quantum bits, entanglement,…
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Qutrit breakthrough brings quantum computers closer
The folks playing with quantum computers have been claiming for years that their gadgets will one day make today’s supercomputers look like quivering lumps of jelly. But so far, their computers have yet to match the calculating prowess of a 10-year old with ADHD. The most exciting work so far has been on universal quantum…
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A new class of photon gun
Photons are easy to produce, at least en masse. But making them one at a time in a controlled fashion is much harder. Until recently the only trick physicists had for this was to reduce the brightness of a beam until it contained only one photon at a time, on average. Of course, the “on…
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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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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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Holographic quantum computing
After a decade or so in the lab, holographic data storage is about to burst into the hardware market big time. Its USP is that holographic data is stored globally rather than at specific sites in the storage medium. It is written using a pair of lasers to create an interference pattern that is recorded…
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When humans become entangled
Something curious is happening at Nicolas Gisin’s lab at the University of Geneva. Gisin is a world expert in entanglement, the ghostly quantum phenomenon in which two or more particles become so deeply linked that they share the same existence, even when far apart. Entanglement is now a routine resource in many labs: it can…
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The quantum graphity question
Physicists have been searching for a quantum theory of gravity some time. Most believe that the new theory will require some kind of modification to general relativity or quantum theory. One of the ideas in vogue at the moment is that general relativity is actually an emergent phenomenon from some deeper physics. Now Tomasz Konopka…