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"An experiment has confirmed that quantum mechanics allows events to occur with no definite causal order," reports an article shared by long-time Slashdot readers UpnAtom and jd. Researchers at the University of Queensland in Australia believe this could link Einstein's general theory of relativity to quantum mechanics, according to Physics World: In classical physics -- and everyday life -- there is a strict causal relationship between consecutive events. If a second event (B) happens after a first event (A), for example, then B cannot affect the outcome of A. This relationship, however, breaks down in quantum mechanics because the temporal spread of a particles's wave function can be greater than the separation in time between A and B. This means that the causal order of A and B cannot be always be distinguished by a quantum particle such as a photon.

In their experiment, Romero, Costa and colleagues created a "quantum switch", in which photons can take two paths. One path involves being subjected to operation A before operation B, while in the other path B occurs before A. The order in which the operations are performed is determined by the initial polarization of the photon as it enters the switch.... The team did the experiment using several different types of operation for A and B and in all cases they found that the measured polarization of the output photons was consistent with their being no definite causal order between when A and B was applied. Indeed, the measurements backed indefinite causal order to a whopping statistical significance of 18 -- well beyond the 5 threshold that is considered a discovery in physics.
Science Magazine applauds the experiments for "obliterating our common sense notion of before and after and, potentially, muddying the concept of causality.

An anonymous reader shares a report: A research team at the University Medical Center Gottingen has created a cochlear implant that uses light to restore auditory responses in deaf gerbils. The study provides a proof-of-concept that combining optical stimulation with genetic manipulation can successfully restore sound perception, and could lead to a new generation of more accurate cochlear implants.

Approximately 360 million people worldwide have hearing impairment. Traditional cochlear implants can partially restore the ability to hear in many of these patients by stimulating ear cells with electrical signals. In such devices, however, the generated current tends to spread around each point of contact, activation of a large population of neurons and limiting the resolution and clarity of sound signals. Christian Wrobel and colleagues tackled this obstacle by designing a light-based cochlear implant. Optical stimulation promises spatially confined activation of neurons in the auditory nerve, potentially yielding spatially precise ear cell stimulation with limited spreading.

rossgneumann writes: A group of physicists has successfully manipulated beams of laser light into an optical mobius strip (abstract). The shape, a classic mindbender all but nonexistent in nature, has never before been seen in such an immaterial form.

An anonymous reader writes In a paper published in Nature (abstract), scientists report successfully measuring the magnetic interaction of two bound electrons of two different strontium (Sr) ions. The two ions were suspended in a quadrupole ion trap (a.k.a. a Paul trap), and the effects of ambient magnetic noise were mitigated by 'restricting the spin evolution [of the electrons] to a decoherence-free subspace that is immune to collective magnetic field noise.' The scientists measured the magnetic interaction of the two electrons as a function of distance and found that the force acting between the two was inversely dependant on the cubed distance between the electrons, consistent with Newton's inverse-cube law.

An anonymous reader writes "In a new feature on the future of high-frequency trading, Wired suggests that neutrino-powered financial trading systems may be coming soon, which would enable extremely low-latency information to be transmitted directly through the center of the Earth between major financial exchanges. If finance becomes the killer app for neutrino communication technology, it may ultimately make Neutrino SETI feasible. Quoting: 'It is only a matter of time, perhaps a few decades, says Alexander Wissner-Gross, a Harvard physicist, before some hedge fund decides it needs a particle accelerator to generate neutrinos, and then everyone will want one. Yes, they travel slower than light, but they indisputably can tunnel through the earth, cutting thousands of miles off an intercontinental message. And just a few days before the Battle of the Quants, right before the bad news about faster-than-light neutrinos, researchers announced they had sent a message by neutrino from the Fermilab accelerator in Chicago to a detector a kilometer away. According to Dan Stancil of North Carolina State University, the signal traveled at "very close to" the speed of light. Unfortunately, the data rate was only about 0.1 bits per second, meaning it would be useless for much more than sending a yes/no signal. "With the right modulation scheme, this could be increased by at least one or two orders of magnitude," Stancil said, adding "I don’t know of a compelling commercial application." But we’ve all heard the (apocryphal) story that Thomas J. Watson of IBM predicted "a world market for maybe five computers."'"

Taco Cowboy writes "Someone from US is claiming that the universe was born spinning and continues to do so around a preferred axis." The full paper has more details. The researchers measured the spin of a number of galaxies in the northern hemisphere; the data indicated a distinct bias toward left-handed spins. "Longo says that the chance that it could be a cosmic accident is something like one in a million. 'If galaxies tend to spin in a certain direction, it means that the overall universe should have a rather large net angular momentum. Since angular momentum is conserved, it seems it [the universe] must have been "born" spinning.'" Naturally, there is some skepticism: "Neta Bahcall, an astrophysicist at Princeton University in the US, feels that there is no solid evidence for a rotating universe. 'The directional spin of spiral galaxies may be impacted by other local gravitational effects,' she said. She believes that this could result in small correlations in spin rotation over distances less than about 200 Mpc – whereas the observable universe is about 14 Gpc in size."

Freddybear writes "Researchers in France have assembled an acoustic superlens from an array of soda cans. The cans act as resonators, and by exciting the array with tailored sound waves, the sound volume can be made to peak in specific volumes less than a few centimeters wide."

Vadim Makarov writes "Physics World reports on researchers demonstrating a full eavesdropper on a quantum key distribution link. Unlike conventional exploits for security vulnerabilities that are often just a piece of software, spying on quantum cryptography required a box full of optics and mixed-signal electronics. Details are published in Nature Communications, and as a free preprint. The vulnerability was known before, but this is the first actual working exploit with secret-key recording confirmed. Patching this loophole is in progress. Disclosure: I am one of the researchers who worked on this."

$RANDOMLUSER writes "A new study described at Physicsworld.com claims that a small percentage of shoddy or self-interested referees can have a drastic effect on published article quality. The research shows that article quality can drop as much as one standard deviation when just 10% of referees do not behave 'correctly.' At high levels of self-serving or random behavior, 'the peer-review system will not perform much better than by accepting papers by throwing (an unbiased) coin.' The model also includes calculations for 'friendship networks' (nepotism) between authors and reviewers. The original paper, by a pair of complex systems researchers, is available at arXiv.org. No word on when we can expect it to be peer reviewed."

gpronger writes "Sticks and Stones May Break My Bones, but Glass Will Certainly Mend Them! The old schoolyard ditty may be changed to reflect developments using metallic glass that will dissolve in situ instead of the traditional stainless steel or titanium hardware, which require removal by surgery once the bone has healed. Physics World reports that researcher Jörg Löffler at ETH Zurich has created an alloy of 60% magnesium, 35% zinc, and 5% calcium, molded in the form of metallic glass. Through rapid cooling, the alloy forms a molecularly amorphous glass that slowly dissolves over time, supporting the injury long enough for healing, then slowly dissolving away."

Tiger4 writes "Cancer researchers in the UK have come up with a way to sniff for lung cancer on the breath. 'From the results, the researchers identified 42 "volatile organic compounds" (VOCs) present in the breath of 83% of cancer patients but fewer than 83% of healthy volunteers. Four of the most reliable were used to develop a nine-sensor array made from tiny gold particles coated with reactive chemicals sensitive to the compounds.' Other sources have picked up the story as well. Obviously, this would be a big breakthrough for rapid screening, and early detection significantly improves outcomes."

evan_arrrr! writes "From the article: Since the early 20th century physicists have known that light carries momentum, but the way this momentum changes as light passes through different media is much less clear. Two rival theories of the time predicted precisely the opposite effect for light incident on a dielectric: one suggesting it pushes the surface in the direction light is traveling; the other suggesting it drags the surface backwards towards the source of light. After 100 years of conflicting experimental results, a team of experimentalists from China believe they have finally found a resolution."

Roland Piquepaille writes "According to UK and US researchers, it should be possible to fight the global warming effects associated with an increase of dioxide levels by using autonomous cloud-seeding ships to spray salt water into the air. This project would require the deployment of a worldwide fleet of 1,500 unmanned ships to cool the Earth even if the level of carbon dioxide doubled. These 300-tonne ships 'would be powered by the wind, but would not use conventional sails. Instead they would be fitted with a number of 20 m-high, 2.5 m-diameter cylinders known as Flettner rotors. The researchers estimate that such ships would cost between £1m and £2m each. This translates to a US$2.65 to 5.3 billion total cost for the ships only."