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The CIA and Jeff Bezos Bet on Quantum Computing - Tom Simonite
The processor in every computer you've used is made from silicon and patterned with transistors that create logic gates—switches that are either on (represented by a 1 in the computer's programming) or off (a 0). D-Wave's processors are also made up of elements that switch between 1 and 0, but they are loops of niobium alloy—there are 512 of them in the newest processor. These loops are known as qubits and can trap electrical current, which circles inside the loops either clockwise (signified by a 0) or counterclockwise (1). Smaller superconducting loops called couplers link the qubits so they can interact and even influence one another to flip between 1 and 0.
This delicate setup is designed so that the layout of qubits conforms to an algorithm that solves a particular kind of optimization problem at the core of many tasks difficult to solve on a conventional processor. It's like a specialized machine in a factory able to do one thing really well, on a particular kind of raw material. Performing a calculation on D-Wave's chip requires providing that raw material, in the form of the numbers to be fed into its hard-coded algorithm. It's done by setting the qubits into a pattern of 1s and 0s, and fine-tuning how the couplers allow the qubits to interact. After a wait of less than a second, the qubits settle into new values that represent a lower state of energy for the processor, and reveal a potential solution to the original problem.
What happens during that crucial wait is a kind of quantum mechanical argument. The qubits enter a strange quantum state where they are simultaneously both 1 and 0, like Schrodinger's cat being both dead and alive, and lock into a strange synchronicity known as entanglement, a phenomenon once described by Einstein as "spooky." That allows the system of qubits to explore every possible final configuration in an instant, before settling into on the one that is simplest or very close to it.
At least, that's what D-Wave's scientists say. Many questions remain about what actually happens inside the company's chips, not least in the heads of the company's own physicists, engineers, and computer scientists.
New results show neutrinos still faster than light - Lisa Grossman
One of the most staggering results in physics – that neutrinos may go faster than light – has not gone away with two further weeks of observations. The researchers behind the jaw-dropping finding are now confident enough in the result that they are submitting it to a peer-reviewed journal.
"The measurement seems robust," says Luca Stanco of the National Institute of Nuclear Physics in Padua, Italy. "We have received many criticisms, and most of them have been washed out."
Faster-than-light neutrino update: What's going on behind the scenes? - Maggie Koerth-Baker
The publication process for a research paper about physics works a little differently than other subjects. That's because of arXiv. Funded by Cornell University, this site posts research papers, before they're formally published in a scientific journal. Unlike most scientific journals, which charge big fees for subscriptions or even to view a single paper, arXiv is free and open to the public. You can read everything published there—more than 700,000 papers about physics, math, computer science, and more. The other big difference: arXiv isn't peer reviewed. At least, not ahead of time.
A lot of the time, when you read a newspaper article about a new study in one of those fields, the study hasn't actually yet been published in a peer-reviewed journal. It's just been posted to arXiv, which sort of becomes a crowd-sourced peer review peer review of its own. Especially for headline-grabbing research making big, bold claims.
That's the background you need to understand what's going on right now with the study that claimed to find neutrinos traveling faster than the speed of light. That announcement was made in an arXiv paper. Putting those results on arXiv was as much a way of saying, "Woah, we just found something crazy, please tell us if you see something we've done wrong," as it was a formal declaration of scientific discovery.
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That's why it's not terribly weird that you're now hearing all sorts of criticism of the original FTL neutrino findings. That's what was supposed to happen. It's also not terribly weird that the original researchers have announced that they're going to re-do the experiment themselves, taking into account some of the big criticisms brought up on arXiv.
Particles break light-speed limit - Geoff Brumfiel
An Italian experiment has unveiled evidence that fundamental particles known as neutrinos can travel faster than light. Other researchers are cautious about the result, but if it stands further scrutiny, the finding would overturn the most fundamental rule of modern physics — that nothing travels faster than 299,792,458 metres per second.
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The idea that nothing can travel faster than light in a vacuum is the cornerstone of Albert Einstein's special theory of relativity, which itself forms the foundation of modern physics. If neutrinos are travelling faster than light speed, then one of the most fundamental assumptions of science — that the rules of physics are the same for all observers — would be invalidated. "If it's true, then it's truly extraordinary," says John Ellis, a theoretical physicist at CERN.
Ereditato says that he is confident enough in the new result to make it public. The researchers claim to have measured the 730-kilometre trip between CERN and its detector to within 20 centimetres. They can measure the time of the trip to within 10 nanoseconds, and they have seen the effect in more than 16,000 events measured over the past two years. Given all this, they believe the result has a significance of six-sigma — the physicists' way of saying it is certainly correct. The group will present their results tomorrow at CERN, and a preprint of their results will be posted on the physics website ArXiv.org.
What's new on the fusion front? - Alan Boyle
ITER is taking the most conventional approach to creating a controlled fusion reaction, which involves magnetic containment of a super-hot plasma inside a doughnut-shaped device known as a tokamak. The European Union and six other nations, including the United States, have divvied up the work load with the aim of completing construction in 2017 and achieving "first plasma" in 2019.
Right now, Oak Ridge National Laboratory and US ITER are testing a fuel delivery system that would fire pellets of ultra-cold deuterium-tritium fuel into the plasma.
"When we send a frozen pellet into a high-temperature plasma, we sometimes call it a 'snowball in hell,'" Oak Ridge physicist David Rasmussen said in an ITER report on the tests at the Dill-D research tokamak in San Diego. "But temperature is really just the measure of the energy of the particles in the plasma. When the deuterium and tritium particles vaporize, ionize and are heated, they move very fast, colliding with enough energy to fuse."
Italian cold fusion machine passes another test - Natalie Wolchover
In the intervening months, Rossi has built a large version of his device that combines many smaller cold fusion modules. At the demo in October, after an initial energy input of 400 watts into each module, each one then produced a sustained, continuous output of 10 kilowatts (470 kW altogether) for three to four hours.
Rossi has not published any details about the inner workings of the E-Cat because the device is not patent-protected, but other cold fusion researchers have theories as to how the process works. Peter Hagelstein, an MIT professor of electrical engineering and computer science and one of the most mainstream proponents of cold fusion research, thinks the process may involve vibrational energy in the metal's lattice driving nuclear transitions that lead to fusion.
