A pair of quantum entangled photons sure makes a cute couple. Of course, the two might have opposite states–one might be spin up and another spin down, for example–but they promise they’ll always stay that way.

They’re also fiercely loyal, respecting their opposite-spin preferences no matter how long-distance their relationship. (That means that by checking the state of one entangled photon, you can instantly know the state of the other, distant photon, a handy way to “teleport” information.) Unfortunately, because the couple is merely two light particles, their shining example of old romance has been too dim for our eyes to see.

Until now. As announced in their recently published Arxiv.org paper, physicists led by Nicolas Gisin at the University of Geneva in Switzerland believe they have found a way to watch this love affair unfold: by boosting the light emitted by one member of a quantum entangled pair, they think they can make this quantum effect visible to a human eye.

Measuring quantum states such as spin up or spin down is like looking at whether a switch is on or off. This closely matches the concept of a bit, a single 1 or 0, in computing. With entangled photons, physicists call these on/off states quantum bits or “qubits.” What an observer would see while observing an entangled photon is really a choice between two states. The observer could then confirm entanglement by checking to see that the photon was loyal to its partner.

In the traditional set-up, two widely separated particle detectors are used to measure the entanglement of the two photons. But Gisin and his colleagues want to let the human eye do some of the work.

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For the first time, physicists say they have witnessed a subatomic particle change its “flavor.” Physicists at OPERA, run by Italy’s national nuclear physics institute, announced yesterday that they have observed one neutrino change its type, or flavor, spontaneously. The experiment solves a 50-year-old physics mystery, and may uncover some of the universe’s hidden mass.

The Mystery

Neutrinos, which come in three different flavors, can have fairly violent births: they can come into the world via nuclear reactions in the sun, particle decay, or collisions in particle accelerators. But, once formed, they seem to ignore almost everything around them, including magnetic fields, electric fields, and matter. In fact, there are trillions of them zipping through each of us every second; they go right through our bodies and keep on moving through the planet itself.

The mystery of “neutrino oscillations” began with the number of neutrinos that should be coming from the sun. Theory predicted a certain number of various flavors to arrive, but observation showed much less:

The neutrino puzzle began with a pioneering and ultimately Nobel Prize winning experiment conducted by US scientist Ray Davis beginning in the 1960s. He observed far fewer neutrinos arriving at the Earth from the Sun than solar models predicted: either solar models were wrong, or something was happening to the neutrinos on their way. [CERN]

In 1969, Bruno Pontecorvo and Vladimir Gribov theorized that the neutrinos weren’t disappearing, they were changing their flavors mid-journey. Though physicists were looking for one type, they weren’t finding what they ordered.

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As opposed to simply energy, the universe is also made of stuff. Not a whole lot of stuff, mind you, at least if you compare the matter we experience to the vast emptiness of space or the preponderance of dark matter. But enough.

The continued prevalence of matter has long been one of my favorite attributes of the universe, given that it allows for the existence of galaxies, and Guinness. However, it’s the source of confusion to physicists. In short, there should have been equal amounts of matter and antimatter present at the creation of the universe, which doesn’t make sense:

If matter and antimatter had come out even in those first moments, they would have instantly destroyed each other, leaving nothing but energy behind [TIME].

But they didn’t; as sure as I’m sitting here, matter won out. And this week, at the Tevatron particle smasher in Illinois, a new clue to the problem has emerged. In a study for Physical Review D, physicist Dmitri Denisov and his colleagues explain that in long-running proton-antiproton collisions (nearly 8 years of them), they saw a slight favoritism toward normal matter in a particular place:

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It sounded again today like the Large Hadron Collider—previously the victim of technical failure, hackers, and avian sabateurs—was cursed. The BBC reported that the world’s largest particle collider would have to shut down at the end of 2011, possibly for an entire year, to address its mechanical problems, according to LHC director Steven Myers. The report states that the faults will delay the machine reaching its full potential for two years [BBC News].

Just one problem, though: While the information came out as another “LHC is broken” news break, Myers actually put forth the intended schedule more than a month ago. The LHC team announced that it would actually extend the physics run through until December 2011, before shutting the accelerator down for a year. The only real delay here has been to the reporting of the story [The Times]. Brian Cox, one of the project scientists, spent the morning tweeting up a storm in protest to the news handling of what he says is just a scheduled shutdown. (A typical tweet reads: “For the very last time – the #lhc story is a pile of merde, as we say at CERN. Scheduled maintenance stops are not bloody news!”)

The LHC will keep running until late next year at 7 trillion electron volts (TeV), as planned. The engineers will go in after that to carry out the planned maintenance on systems in the tunnel that have proven problematic so far; their improvements should allow the LHC to approach what was the goal from the start, doing physics at 14 TeV. In any case, the machine’s upcoming resting time isn’t an emergency shutdown. Particle accelerators are regularly shut down for re-engineering. They are huge, complex instruments, and it’s just impossible to run them full-time like a domestic boiler [The Times].

Related Content:
80beats: LHC Beam Zooms Past 1 Trillion Electron Volts, Sets World Record
80beats: Baguettes and Sabateurs from the Future Defeated: LHC Smashes Particles
DISCOVER: A Tumultuous Year at the LHC
Discoblog: LHC Shut Down By Wayward Baguette, Dropped By Bird Saboteur

Image: Claudia Marcelloni / CERN

While the oft-troubled Large Hadron Collider is starting back up today after a weekend glitch, another big physics project is under way halfway around the world. The British and Japanese researchers behind the project called T2K (Tokai-to-Kamioka) announced their first neutrino detection, the initial step in an experiment to understand these mysterious subatomic particles.

Neutrinos are tiny particles that rarely interact with matter, making them incredibly difficult to study. But physicists have done it by looking for the signature left behind when one of the torrent of neutrinos flying through the Earth at any given time happens to crash into the nucleus of an atom within view of a neutrino detector. Japan’s Super Kamiokande is one of the largest neutrino detectors, and now it has a new mission under the T2K project. The goal is to understand a strange kind of subatomic metamorphosis. These particles come in three types or flavours: electron, muon and tau neutrinos. From earlier experiments, physicists know that neutrinos spontaneously change their flavour, oscillating back and forth from one kind to another. But the details are still hazy [New Scientist].

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Long hyped as the largest science experiment ever built, the Large Hadron Collider now has a world record for doing something: accelerating particles with more energy than any accelerator ever has.

On Sunday evening, at 6:44 p.m. eastern time in the United States, engineers at the Switzerland-based accelerator increased the energy of this “pilot beam”, reaching 1.18 trillion electron volts…. The previous record of 0.98 trillion electron volts has been held by the Tevatron accelerator since 2001 [BBC News].

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Hackers. Leaking liquid helium caused by a faulty connection. International ridicule. And to top it all off, aerial attack by a wayward baguette. Yes, it’s safe to say that things haven’t gone according to plan at the Large Hadron Collider in the last 14 months, but the world’s largest particle smasher is finally—finally!—back online after its Friday restart, with proton beams circulating through this huge underground ring.

The first time protons circled the collider, on Sept. 10, 2008, the event was celebrated with Champagne and midnight pajama parties around the world. But the festivities were cut short a few days later when an electrical connection between a pair of the collider’s giant superconducting electromagnets vaporized [The New York Times].

The initial enthusiasm, it seems, was rather premature—scientists analysis of the failed connection revealed many more that probably couldn’t handle the strain of the energy needed to re-create conditions similar to the Big Bang. During 14 months of repairs dozens of giant superconducting magnets that accelerate particles at the speed of light had to be replaced [BBC News].

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Magnets may have seemed simple when you learned about them in elementary school, but physicists are coaxing some very odd behaviors out of magnetic materials these days. In the latest new development, scientists created the magnetic equivalent of electricity and named the phenomenon “magnetricity.” In the same way that electrically charged particles flow to create an electric current, individual north and south magnetic poles have been observed flowing along to generate a magnetic current.

The basis of the experiment was a refutation of a rule of magnetism observed in our day-to-day lives: No matter how many times you divide a magnet, the resulting fragments will always have both north and south poles. But more than 70 years ago, physicist Paul Dirac theorized that elementary particles should exist that have only a north or south pole, and dubbed these theoretical particles magnetic monopoles. Last month, researchers got closer to spotting a monopole than ever before, when they created ripples that had the same magnetic properties as monopoles.

The new study, published in Nature, describes the phenomenon in a strange, crystalline material known as spin ice. These crystals are made up of pyramids of charged atoms, or ions, arranged in such a way that when cooled to exceptionally low temperatures, the materials show tiny, discrete packets of magnetic charge. Now one of those teams has gone on to show that these “quasi-particles” of magnetic charge can move together, forming a magnetic current just like the electric current formed by moving electrons [BBC News].

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Schrödinger’s Cat may be the most famous thought experiment of all time, but due to its quantum trickiness it must remain in the realm of the hypothetical for the time being. However, researchers suggest they might just be able to pull off a similar, smaller-scale experiment they call Schrödinger’s virus.

The physicist Erwin Schrödinger came up the the feline thought experiment in the 1930s, presenting it as a caution against applying quantum rules to the real, ‘classical’ world…. At its most fundamental level, quantum mechanics says that particles can only exist in discrete states. For example, researchers can measure the direction a particle spins as either ‘up’ or ‘down’, but nothing in between. Yet, as long as no one is looking, the particle exists in a combination of both states simultaneously, a strange blend known as a superposition [Nature News].

Schrödinger proposed an experiment where a cat would be put in box containing a vial of poison gas. A hammer would be suspended ready to smash down on the vial if triggered by the decay of a single atom of radioactive material. If no one looked inside the box, Schrödinger said, the radioactive atom would be in a superposition–both intact and decayed–and therefore the cat would exist in two states as well, being simultaneously alive and dead.

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Researchers in Germany produced element 112 in 1996, and now that it has been recognized by the International Union for Pure and Applied Chemistry, it will be the newest addition to the periodic table of the elements. It’s currently known as ununbium, Latin for ‘one-one-two,’ but it will be given an official name before it’s added to the chart.

The new element is one of only 22 elements that are man-made, and it’s 277 times heavier than hydrogen, making it the weightiest element on the periodic table. To make it, scientists at Germany’s Centre for Heavy Ion Research fused the the nuclei of zinc and lead. The atomic number 112 refers to the sum of the atomic numbers of zinc, which has 30, and lead, which has 82. Atomic numbers denote how many protons are found in the atom’s nucleus [Reuters]. Creating new elements isn’t just a why-not-do-it challenge: It has also helped researchers to understand how nuclear power plants and atomic bombs function [Reuters].

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In the realm of quantum mechanics, atoms and subatomic particles just don’t follow the rules that we’re governed by in the larger world of classical mechanics. For example, the theory of quantum mechanics predicts that two or more particles can become “entangled” so that even after they are separated in space, when an action is performed on one particle, the other particle responds immediately. Scientists still don’t know how the particles send these instantaneous messages to each other, but somehow, once they are entwined, they retain a fundamental connection [LiveScience].

Now, a new study has dragged entanglement a little bit closer to our classical world. Researchers managed to entangle two pairs of vibrating ions so that when the motion of one pair of ions was changed, the other pair reflected the change as well. Previously, researchers have entangled particles in much more esoteric ways, coordinating the spin of electrons or the polarization of photons. With this study, says coauthor John Jost, “We’ve entangled something that has never been entangled before, and it’s the kind of physical, oscillating system you see in the classical world, just much smaller” [LiveScience].

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Three recent studies raised hopes that physicists had caught the first glimpses of dark matter, but the somewhat contradictory results guarantee that researchers will be puzzling over the issue  for some time to come. The latest results come from NASA’s orbiting Fermi Gamma-ray Space Telescope, which was launched last June. The evidence is a reported excess of high-energy electrons and their antimatter counterparts, positrons, which could be created as dark matter particles annihilate or decay [Nature News].

Peter Michelson, principal investigator for the instrument on Fermi that made the detection, cautions that his group is not yet claiming to have found a smoking gun for dark matter. The signal could also come from more mundane sources nearby, such as pulsars, the spinning remnants of supernovae. “But if it isn’t pulsars, it is some new physics,” says Michelson [Nature News]. The new findings are published in Physical Review Letters. Meanwhile, a satellite named PAMELA recently detected higher than expected numbers of positrons, which seems to corroborate the Fermi findings. But results from a balloon experiment conducted high over Antarctica last year add a dash of confusion to the mix.

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By tracing radioactive pollution created by the nuclear tests of the 1950s, researchers have settled the question of whether the human heart creates new cells during a person’s lifespan. “The dogma has always been that cell division in the heart pretty much stops after birth…. In medical school, we teach that you’ll die with the heart cells you’re born with” [Science News], comments cardiovascular expert Charles Murry. However, a new study has overturned this dogma, and found that the heart does regenerate, albeit slowly.

Cell turnover rates can easily be measured in animals by making their cells radioactive and seeing how fast they are replaced. Such an experiment, called pulse-labeling, could not ethically be done in people. But Dr. Frisen realized several years ago that nuclear weapons tested in the atmosphere until 1963 had in fact labeled the cells of the entire world’s population [The New York Times]. The Cold War tests produced a radioactive form of carbon called carbon-14, which was absorbed by plants and worked its way up the food chain; in humans, carbon-14 gets into the DNA of new cells and remains unchanged for the cells’ lives.

Once nuclear tests ended in 1963, levels of carbon-14 began to gradually decline. Because the level of carbon-14 in the atmosphere falls each year, the amount of carbon-14 in the DNA can serve to indicate the cell’s birth date [The New York Times], says lead researcher Jonas Frisén. His team found that people’s hearts have cells that are younger than the people themselves, indicating that new cells have grown since birth. Heart experts say it’s a remarkable use of the nuclear tests’ impacts. “I am very excited about how they have used this novel technology to get something useful out of such a terrible environmental disaster” [Technology Review], says Murry.

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The mysterious stuff known as dark matter may have left a calling card at the edge of the Earth’s atmosphere where a space-faring satellite named PAMELA could pick it up. Researchers are reporting that PAMELA detected a high number of the subatomic particles called positrons, the positively-charged counterpoints to electrons, which could have been created by collisions between dark matter particles. “PAMELA found a number of positrons much higher than expected,” the mission’s principal investigator Piergiorgio Picozza [said]. “Many think this could be a signal from dark matter” [SPACE.com]. But of course, others think there’s a more mundane explanation.

Dark matter is one of the greatest enigmas in astrophysics: It cannot be observed directly, so researchers have to study its effects on normal matter to try to deduce what it’s made of. The top candidates for dark matter, the heavy but invisible stuff that makes up 23 percent of the universe, are weakly-interacting massive particles. Contrary to their WIMPy name, when two of these particles collide, they annihilate each other in a burst of energy and propel a cloud of matter and antimatter particles into space. The theory has been a favorite of physicists for years, but until now, no one had detected evidence of these collisions [Wired].

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Cold fusion is the dream that won’t die for some nuclear physicists. If they could replicate the nuclear reaction that powers our sun under room temperature conditions, the thinking goes, humanity would gain a clean source of nearly limitless energy. Work on cold fusion has been relegated to the margins of science since a much-hyped experiment 20 years ago was discredited, but now a new team of researchers says they’ve conducted experiments that should reinstate the field. “We have compelling evidence that fusion reactions are occurring” at room temperature [EE Times], said lead researcher Pamela Mosier-Boss, of the Space and Naval Warfare Systems Center in San Diego.

On March 23, 1989, physicists Stanley Pons and Martin Fleischmann claimed to have created fusion reactions in a tabletop experiment, at room temperature. [Watch a video of the annoucement here.] Their claims of producing small amounts of excess heat — energy — in their experiments were at first met with excitement, then skepticism and finally derision as other scientists were unable to reproduce the results [Houston Chronicle]. Most physicists eventually concluded that the extra energy was either a fluke or the product of an experimental error.

Mosier-Boss announced her team’s new findings at a meeting of the American Chemical Society yesterday, twenty years to the day since the earlier declaration. She has also published the work in the journal Naturwissenschaft.

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