Monday, August 31, 2015

http://www.theguardian.com/us

Alarming data from China was met with a soothing hint about monetary policy. But treasuries cannot keep pumping cheap credit into a series of asset bubbles

Cartoon by David Simonds showing financiers being helped out by central banker

Like children clinging to their parents, stock market traders turned to their central banks last week as they sought protection from the frightening economic figures coming out of China. Surely, they asked, the central banks would ward off the approaching bogeymen, as they had so many times since the 2008 crash.
The US Federal Reserve came up with the goods. William Dudley, president of the bank’s New York branch, hinted that the interest rate rise many had expected next month was likely to be delayed.
A signal that borrowing costs would remain at rock bottom was all it took. After Black Monday and Wobbly Tuesday, the markets recovered to regain almost all their recent losses.
It was just as if they had said to themselves: who cares if China’s economy is slowing; the “Greenspan put”, which so famously propped up US stock markets during the 1990s and early 2000s with one interest rate cut after another, is still in operation.
The meeting of the world’s most important central bankers in Jackson Hole, Wyoming, this weekend only confirmed the need for Britain, Japan, the eurozone and the US to keep monetary policy loose.
Yet the palliative offered by the Fed is akin to a parent soothing fears with another round of ice-creams despite expanding waistlines and warnings from the dentist and the doctor.

According to some City analysts, the stock markets are pumped with so much cheap credit that a crash is just around the corner. And they worry that when that crash comes, the central banks are all out of moves to prevent the aftershocks from causing a broader collapse.
Since 2008 the Fed has pumped around $4.5 trillion into the financial system. The Bank of England stopped at £375bn. The Bank of Japan is still adding to its post-crash stimulus with around $700bn a year and the Frankfurt-based European Central Bank will have matched its cousin in Tokyo by the end of the year.
In each case, the central bank has adopted quantitative easing, which involves buying government debt to drive up its price. A higher price lowers the returns and encourages investors to go elsewhere in search of gains. It has meant a big shift in the portfolios of fund managers in favour of shares. Apart from a few blips due to the Greek crisis, stock markets have boomed. This summer, the FTSE 100 soared past 2008 levels to top its 1999 peak.
But China, which has borrowed heavily to keep its economy moving, is running out of steam. Beijing has said it does not want to encourage another borrowing boom. But to prevent a crash, it is doing just that. In the last two weeks it has cut interest rates and loosened borrowing limits. It has even invested directly in the market, buying the shares of smaller companies.
So we face the shocking prospect of central bankers, in thrall to stock market gyrations, making the world a more unstable place with promises of yet more cheap credit.
There are a few alternative courses of action that Bank of England governor Mark Carney could still propose. He could tell politicians that the only sustainable way to get their economies moving is with hard cash from taxed wealth and incomes. If that is too unpalatable, governments should borrow directly to fund public infrastructure and productivity improvements.
And if the government is too embarrassed to admit to voters that it needs to borrow money, then the least central banks can do is sign deals with high street banks to lend, rather than hoping they will take QE funds and do something useful with them. Because the evidence is already there for all to see that investors would prefer to pump the money into the stock market and property, both of them inherently unstable and prone to violent crashes.

Google feels the EU heat

‘We have owned the internet,” Barack Obama crowed in a video interview this February. “Our companies have created it, expanded it, perfected it.” But from tax to privacy and now a string of antitrust investigations, one of those companies, Google, is under attack on multiple fronts in Europe.
The US president argued that what has been presented as high-minded intervention by regulators is in fact a commercially driven bid to protect old-world technology companies from the Silicon Valley invaders.
Europe’s most powerful regulator, the Brussels competition policy chief Margrethe Vestager, has taken aim at Google Shopping, its price-comparison service. In April, she launched a legal process that could result in a big fine. On Thursday, the search giant filed a 150-page rebuttal.
First of all, Google says it has not choked off traffic to rival shopping price sites – the traffic it sends to these kinds of sites has increased by 227% over a decade (its own data shows). Sounds like a big number. Until you look at the growth in Google’s own traffic over that period. The number of searches worldwide now stands at somewhere near 1.2 trillion a year – an increase of 750% in a decade.
Google also wants its shopping service considered as part of a much larger group that includes actual retailers, like Amazon, and marketplaces, like eBay, where people also go to compare prices. Perhaps, but these are very different businesses. The capital needed to launch an online retailer, let alone one with a global presence and a one-day delivery guarantee, is much larger than the funding required for a price-comparison startup.
Google’s strongest point is that forcing a company to offer its services to rivals is a drastic measure normally reserved for monopoly utilities. Google is very useful, but it is not water or electricity. Google Shopping is a very niche service.
The argument about fair price comparison is a sideshow given the much bigger worries about privacy, security and tax that currently dog the digital world. But a victory for regulators here could lead to more assaults – on Google’s flight-comparison service and maps. Vestager has also launched an investigation into Android, the group’s market-leading phone software. Obama may be called on to cheer the home team again before this fight is over.

Two sides to the national living wage?

George Osborne has already claimed credit for Sainsbury’s increasing the base pay of its shop floor staff by 4%. “Britain deserves a pay rise so great Sainsbury’s staff will be paid at least national living wage early with biggest increases in 10 years,” he tweeted last week.
It is a indeed a credit to the chancellor that he has put pay on the agenda for Britain’s supermarkets, the country’s largest private employers, by announcing a national living wage in the budget last month. However, Sainsbury’s announcement is just one side of the coin: the other side is how it will finance the pay increase.
The Office for Budget Responsibility has estimated that the chancellor’s national living wage will lead to 60,000 job losses as companies fund the higher minimum pay by cutting jobs. Moody’s, the credit rating agency, has warned retailers could close stores, increase prices and employ more under-25s – who do not qualify for the national living wage. Perks for staff, such as in-store discounts, could also be at risk.
Sainsbury’s did not downgrade its profit forecasts at the same time as announcing the pay increase, so it must have found the money from somewhere – time will tell where.

By Anthony Mirhaydari 2 hours ago

The bad omens are building in the stock market.

Set aside the situation in China, where data released Tuesday showed manufacturing activity dropped last month to a three-year low and reached contractionary territory — the given reason for Tuesday’s market tumble. Forget for a moment about the Federal Reserve, which seems committed to raising interest rates this month for the first time since 2006. The stock market itself is warning of big trouble.
Collectively representing the opinions of countless individual participants, it pays to pay attention to what is the greatest future discounting mechanism in human history.
Related: The Troubling Truth Revealed by the Stock Market’s Nosedive

The technical damage to stock prices has been severe. The S&P 500 has suffered its first "Death Cross" — a plunge of the 50-day moving average below the 200-day moving average, a sign of lost medium-term momentum — in four years. The long-term trend is at risk, as the index closed Monday’s session below its 12-month moving average, a strong predictor of bear markets.

^SPX data by YCharts

Unless stocks mount a historic charge higher here — ending September 6 percent higher — it could be game over for the bull market. History isn't on their side.

August ended with more than a 5 percent loss on the S&P 500, the worst performance for the month in 17 years and down 7.5 percent from its July high. According to Jason Goepfert at SentimenTrader, after August losses of this magnitude since 1928, September sported a positive return only 4 out of 13 times, posting an average loss of 5.4 percent. When they rallied, stocks only rose above August's close by an average of 1.4 percent. When they fell, the drop averaged 8.3 percent.

In his words, that's the data reveals a "terrible risk/reward ratio" in stocks right now.

The kicker is that the decline we've already seen in stocks is setting off alarm bells in the macroeconomic models created by Wall Street trading desks. Bank of America Merrill Lynch Economist Michael Hanson's model puts the probability of recession at nearly 50 percent based on the 15 percent annualized drop in stocks over the last six months.

Admittedly, the model flashed a 59 percent chance of recession during the 2011 market slide. But should Goepfert's analysis come to fruition, the odds are likely to rise.

Moreover, the economy was saved in 2011 by aggressive monetary policy efforts, including the start of the Fed's "Operation Twist" maturity extension program, the expansion of dollar liquidity swap lines to Europe that November and the European Central Bank's three-year bank liquidity stimulus.

A repeat performance would be hard to pull off when, at this point, market turmoil only appears set to forestall the start of policy tightening. Citigroup rate strategist Jabaz Mathai admits a further 10 percent drop in stocks would mean the "Fed will most likely not hike, no matter what the payrolls data is" for August when those numbers are released on Sept. 4.

^VIX data by YCharts

Goldman Sachs looks at it from a different angle, noting the recent rise in the CBOE Volatility Index (VIX), known as Wall Street's "fear gauge." The current level is equal to the median the VIX has been trading at over the last three recessions. VIX levels this high for extended periods, in their analysis, "are rare outside recessions."

Deutsche Bank's chief strategist Binky Chadha recently wrote to clients that equity market corrections of 10 percent or more are "rare outside recessions," with only 13 occurrences in the last 65 years in the context of a falling unemployment rate.

On the flip side, should the warnings prove false and the bulls manage to push stocks higher in the weeks to come, the bad omens turn very positive indeed: Recoveries from non-recession corrections average 8 percent one month later, 10 percent three months later and 19 percent six months later.

A revolution comes in layers

The "energy crisis" hit like a locomotive in the 1970s. Today's "energy revolution" didn't happen suddenly. It grew out millions of innovations, processes, and decisions.

By John Yemma, Editor-at-Large August 30, 2015

JEAN-PAUL PELISSIER/REUTERS

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A crisis usually arrives amid blaring headlines and a wildfire of worry. That was how the “energy crisis” of the late 20th century seemed. The era of plentiful oil was over. Middle East producers enacted embargoes. Gas lines stretched for blocks. In 1977, then-President Jimmy Carter called the battle against energy shortages “the moral equivalent of war.”
A genuine revolution often arrives quietly, barely noticed because it unfolds gradually and cumulatively. That’s today’s energy revolution.
Oil prices are tumbling. New extraction procedures have made oil and natural gas abundant. But that hasn’t slowed solar, wind, geothermal, and other alternative power sources. Conservation hasn’t slowed either. LED lights and less-voracious appliances are curbing consumption and forcing the mothballing of carbon-spewing power plants.
And that is only the beginning. The next wave is batteries. As you’ll see in David Unger’s cover story (click here), better batteries will make solar and wind power effective when the sun doesn’t shine and the winds don’t blow. As major undertakings such as Elon Musk’s Tesla “gigafactory” improve lithium-ion batteries and manufacture them at industrial scale, prices will decrease and use will surge.

When houses, offices, and industrial plants can produce and store energy sufficient for their needs, then power plants, utility companies, and the electric grid – that 450,000-mile network of high-voltage transmission lines strung across the US that is perhaps the most complex and vulnerable installation on the planet – become less important. There will still be a need for always-available, industrial-scale electricity. But power consumption is already diminishing year by year. Ahead lies a shakeout of the 7,300 power plants in the US, especially the dirtier and less efficient ones.
The energy crisis that gripped the world in the late 20th century was not fought and won. It was worked on year by year by inventors and improvers. Ideas were tried, tested, reconfigured, and enhanced. A Bell Labs physicist came up with the first solar cell in 1941; an engineer at General Electric invented the light-emitting diode in 1962; three scientists from Oxford University conceived of the lithium-ion battery in 1980. Today’s rooftop solar arrays, low-energy lightbulbs, and the power packs that run our cellphones – and soon our houses and offices – are the product of thousands of improvements layered atop those early concepts.
Invention is important. Improvement is crucial. The energy crisis of the late 20th century was a big problem. In the middle of it, it did feel like the moral equivalent of war. But piece by piece, the problem was worked out. Shortage turned into abundance.
There are other crises today. Global climate change is perhaps the biggest of them. The solution will involve millions of ideas, products, and techniques that will improve year after year. A crisis doesn’t go away by ignoring it. It is solved by working on it.

Sunday, August 30, 2015

Explaining EmDrive, the ‘physics-defying’ thruster even NASA is puzzled over

http://www.digitaltrends.com/

By Brendan Hesse — August 30, 2015

NASA

Even if you don’t keep up with developments in space propulsion technology, you’ve still probably heard about the EmDrive by now. You’ve probably seen headlines declaring it as the key to interstellar travel, and claims that it will drastically reduce trips across our solar system, making our dreams of people walking on other planets even more of a reality. There have even been claims that this highly controversial technology is the key to creating warp drives.

These are bold claims, and as the great cosmologist and astrophysicist Carl Sagan once said, “extraordinary claims require extraordinary evidence.” With that in mind, we thought it’d be helpful to break down what we know about the enigmatic EmDrive, and whether or not it is, in fact, the key to mankind exploring the stars. So without further ado, here’s absolutely everything you need to know about the world’s most puzzling propulsion device.
What is the EmDrive?

See, the EmDrive is a conundrum. First designed in 2001 by aerospace engineer Roger Shawyer, the technology can summed up as a propellantless propulsion system, meaning that the engine doesn’t use fuel to cause a reaction. By removing the need for fuel, a craft would be substantially lighter, and therefore easier to move (and cheaper to make, theoretically). In addition, the hypothetical drive would also be able to reach extremely high speeds — we’re talking potentially getting humans to the outer reaches of the solar system in a matter of months.

We’re talking potentially getting humans to the outer reaches of the solar system in a matter of months.

The issue is, the entire concept of a reactionless drive is inconsistent with Newton’s conservation of momentum, which states that within a closed system, linear and angular momentum remain constant regardless of any changes that take place within said system. More plainly: Unless outside force is applied, an object will not move. Reactionless drives are named as such because they lack the “reaction” defined in Newton’s third law: “For every action there is an equal and opposite reaction.” But this goes against our current fundamental understanding of physics, as for an action (propulsion of a craft) to take place without a reaction (ignition of fuel and expulsion of mass) is impossible. In order for such a thing to occur, it would mean an as-yet-undefined phenomena is taking place, or our understanding of physics is completely wrong.
How does the EmDrive “work?”

Setting aside the potentially physics-breaking improbabilities the technology, let’s break down in simple terms how the proposed drive operates. The EmDrive is what is called an RF resonant cavity thruster, and is one of several hypothetical machines that use this model. These designs are said to work by having a magnetron push microwaves into a closed truncated cone, then push against the short end of the cone, and propel the craft forward. This is in contrast to the form of propulsion current spacecraft use, which instead burn large quantities of fuel to expel massive amount of energy and mass to rocket the craft into the air. An often-used metaphor for the inefficacy of this is to compare the particles pushing against the enclosure and producing thrust to the act of sitting in a car and pushing a steering wheel to move the car forward.

While tests have been done on experimental versions of the drive with low energy inputs produced very minimal, resulting in a few micronewtons of thrust (about as much force as the weight of a penny), none of the findings have ever been published in a peer-reviewed journal. That means that any and all purportedly positive test results, and the claims of those who have a vested interest in the technology, should be taken with a very big grain of skepticism-flavored salt. It’s likely that the thrust recorded was due to interference or an unaccounted error with equipment. Until the tests have been verified through the proper scientific and peer-reviewed processes, one can assume the drive does not yet work. Still, it’s interesting to note the number of people who have tested the drive and reported achieving thrust:
In 2001, Shawyer was given a £45,000 grant from the British government to test the EmDrive. His test was claimed to have achieved 0.016 Newtons of force and required 850 watts of power, but no peer review of the tests verified this. It’s worth noting, however, that this number was low enough it was potentially an experimental error.
In 2008, Yang Juan and a team of Chinese researches at the Northwestern Polytechnical University allegedly verified the theory behind RF resonant cavity thrusters, and subsequently built their own version in 2010, testing the drive multiple times from 2012-2014. Tests results were purportedly positive, achieving up yo 750 mN (micronewtons) of thrust, and requiring 2,500 watts of power.
In 2014, NASA researchers, tested their own version of an EmDrive, including in a hard vacuum. Once again, the group reported thrust (about 1/1000 of Shawyer’s claims), and once again, the data was never published through peer-reviewed sources. Other NASA groups are skeptical of researchers’ claims, but in their paper, it is clearly stated that these findings neither confirm or refute the drive, instead calling for further tests.
Most recently, in 2015, that same NASA group tested a version of chemical engineer Guido Fetta’s Cannae Drive (née Q Drive), and reported positive net thrust. Similarly, a research group at Dresden University of Technology also tested the drive, again reporting thrust, both predicted and unexpected.
Implications of a working EmDrive

From the sections above, it becomes easy to see how many in the scientific community are wary of EmDrive and RF resonant cavity thrusts altogether. But on the other hand, it raises a few questions: Why is there such a interest in the technology, and why do so many people wish to test it? What exactly are the claims being made about the drive that make it such an attractive idea? While everything from atmospheric temperature-controlling satellites, to safer and more efficient automobiles have been drummed up as potential applications for the drive, the real draw of the technology — and the impetus for its creation in the first place — is the implications for space travel.

Spacecraft equipped with a reactionless drive could potentially make it to the Moon in just a few hours; to Mars in two to three months; and to Pluto within two years. These are extremely bold claims, but if the EmDrive does turn out to be a legitimate technology, they may not be all that outlandish after all. And with no need to pack several tons-worth of fuel, spacecraft become cheaper and easier to produce, and far lighter. For NASA and other such organizations, including the numerous private space corporations like SpaceX, lightweight, affordable spacecraft that can travel to parts of space fast are something of a unicorn. Still, in order for that to become a reality, the science has to add up.

Shawyer is adamant that there is no need for pseudo science or quantum theories in order to explain how EmDrive works. Instead, he believes that current models of Newtonian physics offer an explanation, and has written papers on the subject, one of which is currently being peer reviewed. He expects the paper to be published sometime this year. While in the past Shawyer has been criticized by other scientists for incorrect and inconsistent science, if the paper does indeed get published, it may in fact begin to legitimize the EmDrive, and spur more testing and research.

Spacecraft equipped with a reactionless drive could potentially make it to the Moon in just a few hours.

Despite his insistence that the drive behaves within the laws of physics, it hasn’t prevented him from making bold assertions regarding EmDrive. Shawyer has gone on record saying that this new drive produced warp bubbles which allow the drive to move, claiming that this is how NASA’s test results were likely achieved. Assertions such as these have garnered much interest online, but have no clear supporting data and will (at the very least) require extensive testing and debate in order to be taken seriously by the scientific community — the majority of which remain skeptical of Shawyer’s claims.

Colin Johnston of the Armagh Planetarium wrote an extensive critique of the EmDrive and the inconclusive findings of numerous tests. Similarly, Corey S. Powell of Discovery wrote his own indictment of both Shawyer’s EmDrive and Fetta’s Cannae Drive, as well as the recent fervor over NASA’s findings. Both point out the need for greater discretion when reporting on such instances. Professor and mathematical physicist, John C. Baez expressed his exhaustion at the conceptual technology’s persistence in debates and discussions, calling the entire notion of a reactionless drive “baloney.” His impassioned dismissal echoes the sentiments of many others. Elsewhere, however, Shawyer’s EmDrive has been met with enthusiasm, including the website NASASpaceFlight.com, which is where the information about the most recent Eagleworks’ tests was first posted, and the New Scientist Journal, which published a favorable and optimistic paper on EmDrive. (New Scientist has gone on to make a statement that, despite their enduring excitement over the idea, they should have shown more tact when writing on the controversial subject).

Clearly, the EmDrive and RF resonant cavity thruster technology have a lot to prove. There’s no denying that the technology is an exciting thought, and that the number of “successful” tests are interesting, but one must keep in mind the physics preventing the EmDrive from gaining any traction, and the rather curious lack of peer-reviewed studies done on the subject. If the EmDrive is so groundbreaking (and works), surely people like Shawyer would be clamoring for peer-reviewed verification. A demonstrably working EmDrive could open up exciting possibilities for both space and terrestrial travel — not to mention call into question our entire understanding of physics. However, until that comes to pass, the EmDrive will remain as nothing more than science fiction.

Fat Bikes – Are Fat Bikes Fun To Ride?

Saturday, August 29, 2015

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Quantum weirdness proved real in first loophole-free experiment

Daily news

28 August 2015

https://www.newscientist.com/

Quantum weirdness proved real in first loophole-free experiment

Welcome to quantum reality (Image: Julie Guiche/Picturetank)
It’s official: the universe is weird. Our everyday experience tells us that distant objects cannot influence each other, and don’t disappear just because no one is looking at them. Even Albert Einstein was dead against such ideas because they clashed so badly with our views of the real world.
But it turns out we’re wrong – the quantum nature of reality means, on some level, these things can and do actually happen. A groundbreaking experiment puts the final nail in the coffin of our ordinary “local realism” view of the universe, settling an argument that has raged through physics for nearly a century.
Teams of physicists around the world have been racing to complete this experiment for decades. Now, a group led by Ronald Hanson at Delft University of Technology in the Netherlands has finally cracked it. “It’s a very nice and beautiful experiment, and one can only congratulate the group for that,” says Anton Zeilinger, head of one of the rival teams at the University of Vienna, Austria. “Very well done.”
To understand what Hanson and his colleagues did, we have to go back to the 1930s, when physicists were struggling to come to terms with the strange predictions of the emerging science of quantum mechanics. The theory suggested that particles could become entangled, so that measuring one would instantly influence the measurement of the other, even if they were separated by a great distance. Einstein dubbed this “spooky action at a distance”, unhappy with the implication that particles could apparently communicate faster than any signal could pass between them.
What’s more, the theory also suggested that the properties of a particle are only fixed when measured, and prior to that they exist in a fuzzy cloud of probabilities.
Nonsense, said Einstein, who famously proclaimed that God does not play dice with the universe. He and others were guided by the principle of local realism, which broadly says that only nearby objects can influence each other and that the universe is “real” – our observing it doesn’t bring it into existence by crystallising vague probabilities. They argued that quantum mechanics was incomplete, and that “hidden variables” operating at some deeper layer of reality could explain the theory’s apparent weirdness.

On the other side, physicists like Niels Bohr insisted that we just had to accept the new quantum reality, since it explained problems that classical theories of light and energy couldn’t handle.

Test it out

It wasn’t until the 1960s that the debate shifted further to Bohr’s side, thanks to John Bell, a physicist at CERN. He realised that there was a limit to how connected the properties of two particles could be if local realism was to be believed. So he formulated this insight into a mathematical expression called an inequality. If tests showed that the connection between particles exceeded the limit he set, local realism was toast.
“This is the magic of Bell’s inequality,” says Zeilinger’s colleague Johannes Kofler. “It brought an almost purely philosophical thing, where no one knew how to decide between two positions, down to a thing you could experimentally test.”
And test they did. Experiments have been violating Bell’s inequality for decades, and the majority of physicists now believe Einstein’s views on local realism were wrong. But doubts remained. All prior experiments were subject to a number of potential loopholes, leaving a gap that could allow Einstein’s camp to come surging back.
“The notion of local realism is so ingrained into our daily thinking, even as physicists, that it is very important to definitely close all the loopholes,” says Zeilinger.

Loophole trade-off

A typical Bell test begins with a source of photons, which spits out two at the same time and sends them in different directions to two waiting detectors, operated by a hypothetical pair conventionally known as Alice and Bob. The pair have independently chosen the settings on their detectors so that only photons with certain properties can get through. If the photons are entangled according to quantum mechanics, they can influence each other and repeated tests will show a stronger pattern between Alice and Bob’s measurements than local realism would allow.
But what if Alice and Bob are passing unseen signals – perhaps through Einstein’s deeper hidden layer of reality – that allow one detector to communicate with the other? Then you couldn’t be sure that the particles are truly influencing each other in their instant, spooky quantum-mechanical way – instead, the detectors could be in cahoots, altering their measurements. This is known as the locality loophole, and it can be closed by moving the detectors far enough apart that there isn’t enough time for a signal to cross over before the measurement is complete. Previously Zeilinger and others have done just that, including shooting photons between two Canary Islands 144 kilometres apart.
Close one loophole, though, and another opens. The Bell test relies on building up a statistical picture through repeated experiments, so it doesn’t work if your equipment doesn’t pick up enough photons. Other experiments closed this detection loophole, but the problem gets worse the further you separate the detectors, as photons can get lost on the way. So moving the detectors apart to close the locality loophole begins to widen the detection one.
“There’s a trade-off between these two things,” says Kofler. That meant hard-core local realists always had a loophole to explain away previous experiments – until now.
“Our experiment realizes the first Bell test that simultaneously addressed both the detection loophole and the locality loophole,” writes Hanson’s team in a paper detailing the study. Hanson declined to be interviewed because the work is currently under review for publication in a journal.

Entangled diamonds

In this set-up, Alice and Bob sit in two laboratories 1.3 kilometres apart. Light takes 4.27 microseconds to travel this distance and their measurement takes only 3.7 microseconds, so this is far enough to close the locality loophole.

Each laboratory has a diamond that contains an electron with a property called spin. The team hits the diamonds with randomly produced microwave pulses. This makes them each emit a photon, which is entangled with the electron’s spin. These photons are then sent to a third location, C, in between Alice and Bob, where another detector clocks their arrival time.
If photons arrive from Alice and Bob at exactly the same time, they transfer their entanglement to the spins in each diamond. So the electrons are entangled across the distance of the two labs – just what we need for a Bell test. What’s more, the electrons’ spin is constantly monitored, and the detectors are of high enough quality to close the detector loophole.
But the downside is that the two photons arriving at C rarely coincide – just a few per hour. The team took 245 measurements, so it was a long wait. “This is really a very tough experiment,” says Kofler.
The result was clear: the labs detected more highly correlated spins than local realism would allow. The weird world of quantum mechanics is our world.
“If they’ve succeeded, then without any doubt they’ve done a remarkable experiment,” says Sandu Popescu of the University of Bristol, UK. But he points out that most people expected this result – “I can’t say everybody was holding their breath to see what happens.” What’s important is that these kinds of experiments drive the development of new quantum technology, he says.
One of the most important quantum technologies in use today is quantum cryptography. Data networks that use the weird properties of the quantum world to guarantee absolute secrecy are already springing up across the globe, but the loopholes are potential bugs in the laws of physics that might have allowed hackers through. “Bell tests are a security guarantee,” says Kofler. You could say Hanon’s team just patched the universe.

Freedom of choice

There are still a few ways to quibble with the result. The experiment was so tough that the p-value – a measure of statistical significance – was relatively high for work in physics. Other sciences like biology normally accept a p-value below 5 per cent as a significant result, but physicists tend to insist on values millions of times smaller, meaning the result is more statistically sound. Hanson’s group reports a p-value of around 4 per cent, just below that higher threshold.
That isn’t too concerning, says Zeilinger. “I expect they have improved the experiment, and by the time it is published they’ll have better data,” he says. “There is no doubt it will withstand scrutiny.”
And there is one remaining loophole for local realists to cling to, but no experiment can ever rule it out. What if there is some kind of link between the random microwave generators and the detectors? Then Alice and Bob might think they’re free to choose the settings on their equipment, but hidden variables could interfere with their choice and thwart the Bell test.
Hanson’s team note this is a possibility, but assume it isn’t the case. Zeilinger’s experiment attempts to deal with this freedom of choice loophole by separating their random number generators and detectors, while others have proposed using photons from distant quasars to produce random numbers, resulting in billions of years of separation.
None of this helps in the long run. Suppose the universe is somehow entirely predetermined, the flutter of every photon carved in stone since time immemorial. In that case, no one would ever have a choice about anything. “The freedom of choice loophole will never be closed fully,” says Kofler. As such, it’s not really worth experimentalists worrying about – if the universe is predetermined, the complete lack of free will means we’ve got bigger fish to fry.
So what would Einstein have made of this new result? Unfortunately he died before Bell proposed his inequality, so we don’t know if subsequent developments would have changed his mind, but he’d likely be enamoured with the lengths people have gone to prove him wrong. “I would give a lot to know what his reaction would be,” says Zeilinger. “I think he would be very impressed.”

Journal reference: arxiv.org/abs/1508.05949v1

Dr. Edgar Mitchell ★ UFO Interview 2013 Aliens Are Real And Watching Us ...

Thursday, August 27, 2015

Progress to Smaller, Cheaper Particle Colliders and efficient antimatter production

Researchers from the U.S. Department of Energy’s (DOE) SLAC National Accelerator Laboratory and the University of California, Los Angeles have demonstrated a new, efficient way to accelerate positrons, the antimatter opposites of electrons. The method may help boost the energy and shrink the size of future linear particle colliders – powerful accelerators that could be used to unravel the properties of nature’s fundamental building blocks.

The scientists had previously shown that boosting the energy of charged particles by having them “surf” a wave of ionized gas, or plasma, works well for electrons. While this method by itself could lead to smaller accelerators, electrons are only half the equation for future colliders. Now the researchers have hit another milestone by applying the technique to positrons at SLAC’s Facility for Advanced Accelerator Experimental Tests (FACET), a DOE Office of Science User Facility.

“Together with our previous achievement, the new study is a very important step toward making smaller, less expensive next-generation electron-positron colliders,” said SLAC’s Mark Hogan, co-author of the study published today in Nature. “FACET is the only place in the world where we can accelerate positrons and electrons with this method.”

Simulation of high-energy positron acceleration in an ionized gas, or plasma – a new method that could help power next-generation particle colliders. The image shows the formation of a high-density plasma (green/orange color) around a positron beam moving from the bottom right to the top left. Plasma electrons pass by the positron beam on wave-like trajectories (lines). (W. An/UCLA)

Future particle colliders will require highly efficient acceleration methods for both electrons and positrons. Plasma wakefield acceleration of both particle types, as shown in this simulation, could lead to smaller and more powerful colliders than today’s machines. (F. Tsung/W. An/UCLA/SLAC National Accelerator Laboratory)

Nature - Multi-gigaelectronvolt acceleration of positrons in a self-loaded plasma wakefield

Shrinking Particle Colliders

Researchers study matter’s fundamental components and the forces between them by smashing highly energetic particle beams into one another. Collisions between electrons and positrons are especially appealing, because unlike the protons being collided at CERN’s Large Hadron Collider – where the Higgs boson was discovered in 2012 – these particles aren’t made of smaller constituent parts.

“These collisions are simpler and easier to study,” said SLAC’s Michael Peskin, a theoretical physicist not involved in the study. “Also, new, exotic particles would be produced at roughly the same rate as known particles; at the LHC they are a billion times more rare.”

However, current technology to build electron-positron colliders for next-generation experiments would require accelerators that are tens of kilometers long. Plasma wakefield acceleration is one way researchers hope to build shorter, more economical accelerators.

Previous work showed that the method works efficiently for electrons: When one of FACET’s tightly focused bundles of electrons enters an ionized gas, it creates a plasma “wake” that researchers use to accelerate a trailing second electron bunch.

Abstract

Electrical breakdown sets a limit on the kinetic energy that particles in a conventional radio-frequency accelerator can reach. New accelerator concepts must be developed to achieve higher energies and to make future particle colliders more compact and affordable. The plasma wakefield accelerator (PWFA) embodies one such concept, in which the electric field of a plasma wake excited by a bunch of charged particles (such as electrons) is used to accelerate a trailing bunch of particles. To apply plasma acceleration to electron–positron colliders, it is imperative that both the electrons and their antimatter counterpart, the positrons, are efficiently accelerated at high fields using plasmas. Although substantial progress has recently been reported on high-field, high-efficiency acceleration of electrons in a PWFA powered by an electron bunch, such an electron-driven wake is unsuitable for the acceleration and focusing of a positron bunch. Here we demonstrate a new regime of PWFAs where particles in the front of a single positron bunch transfer their energy to a substantial number of those in the rear of the same bunch by exciting a wakefield in the plasma. In the process, the accelerating field is altered—‘self-loaded’—so that about a billion positrons gain five gigaelectronvolts of energy with a narrow energy spread over a distance of just 1.3 meters. They extract about 30 per cent of the wake’s energy and form a spectrally distinct bunch with a root-mean-square energy spread as low as 1.8 per cent. This ability to transfer energy efficiently from the front to the rear within a single positron bunch makes the PWFA scheme very attractive as an energy booster to an electron–positron collider.

Plasma acceleration

From Wikipedia, the free encyclopedia

Plasma acceleration is a technique for accelerating charged particles, such as electrons, positrons and ions, using an electric field associated with electron plasma wave or other high-gradient plasma structures (like shock and sheath fields). The plasma acceleration structures are created either using ultra-short laser pulses or energetic particle beams that are matched to the plasma parameters. These techniques offer a way to build high performance particle accelerators of much smaller size than conventional devices. The basic concepts of plasma acceleration and its possibilities were originally conceived by Toshiki Tajima and Prof. John M. Dawson of UCLA in 1979.^[1] Initial designs of experiment for "wakefield" were conceived at UCLA by the group of Prof. Chan Joshi.^[2] Current experimental devices show accelerating gradients several orders of magnitude better than current particle accelerators.
Plasma accelerators have immense promise for innovation of affordable and compact accelerators for various applications ranging from high energy physics to medical and industrial applications. Medical applications include betatron and free-electron light sources for diagnostics or radiation therapy and protons sources for hadron therapy. Plasma accelerators generally use wakefields generated by plasma density waves. However, plasma accelerators can operate in many different regimes depending upon the characteristics of the plasmas used.
For example, an experimental laser plasma accelerator at Lawrence Berkeley National Laboratory accelerates electrons to 1 GeV over about 3.3 cm (5.4x10²⁰ g_n),^[3] and one at the SLAC conventional accelerator (highest electron energy accelerator) requires 64 m to reach the same energy. Similarly, using plasmas an energy gain of more than 40 GeV was achieved using the SLAC SLC beam (42 GeV) in just 85 cm using a plasma wakefield accelerator (8.9x10²⁰ g_n).^[4] Once fully developed, the technology could replace many of the traditional RF accelerators currently found in particle colliders, hospitals and research facilities.
The Texas Petawatt laser facility at the University of Texas at Austin accelerated electrons to 2 GeV over about 2 cm (1.6x10²¹ g_n).^[5] This record was broken (by more than 2x) in 2014 by the scientists at the BELLA (laser) Center at the Lawrence Berkeley National Laboratory, when they produced electron beams up to 4.25 GeV.^[6]
In late 2014, researchers from SLAC National Accelerator Laboratory using the Facility for Advanced Accelerator Experimental Tests (FACET) published proof of the viability of plasma acceleration technology. It was shown to be able to achieve 400 to 500 times higher energy transfer compared to a general linear accelerator design. ^[7]^[8]

Concept

A plasma consists of fluid of positive and negative charged particles, generally created by heating or photo-ionizing (direct / tunneling / multi-photon / barrier-suppression) a dilute gas. Under normal conditions the plasma will be macroscopically neutral (or quasi-neutral), an equal mix of electrons and ions in equilibrium. However, if a strong enough external electric or electromagnetic field is applied, the plasma electrons, which are very light in comparison to the background ions (at least by a factor of 1836), will separate spatially from the massive ions creating a charge imbalance in the perturbed region. A particle injected into such a plasma would be accelerated by the charge separation field, but since the magnitude of this separation is generally similar to that of the external field, apparently nothing is gained in comparison to a conventional system that simply applies the field directly to the particle. But, the plasma medium acts as the most efficient transformer (currently known) of the transverse field of an electromagnetic wave into longitudinal fields of a plasma wave. In existing accelerator technology various appropriately designed materials are used to convert from transverse propagating extremely intense fields into longitudinal fields that the particles can get a kick from. This process is achieved using two approaches: standing-wave structures (such as resonant cavities) or traveling-wave structures such as disc-loaded waveguides etc. But, the limitation of materials interacting with higher and higher fields is that they eventually get destroyed through ionization and breakdown. Here the plasma accelerator science provides the breakthrough to generate, sustain, and exploit the highest fields ever produced by science in the laboratory.
What makes the system useful is the possibility of introducing waves of very high charge separation that propagate through the plasma similar to the traveling-wave concept in the conventional accelerator. The accelerator thereby phase-locks a particle bunch on a wave and this loaded space-charge wave accelerates them to higher velocities while retaining the bunch properties. Currently, plasma wakes are excited by appropriately shaped laser pulses or electron bunches. Plasma electrons are driven out and away from the center of wake by the ponderomotive force or the electrostatic fields from the exciting fields (electron or laser). Plasma ions are too massive to move significantly and are assumed to be stationary at the time-scales of plasma electron response to the exciting fields. As the exciting fields pass through the plasma, the plasma electrons experience a massive attractive force back to the center of the wake by the positive plasma ions chamber, bubble or column that have remained positioned there, as they were originally in the unexcited plasma. This forms a full wake of an extremely high longitudinal (accelerating) and transverse (focusing) electric field. The positive charge from ions in the charge-separation region then creates a huge gradient between the back of the wake, where there are many electrons, and the middle of the wake, where there are mostly ions. Any electrons in between these two areas will be accelerated (in self-injection mechanism). In the external bunch injection schemes the electrons are strategically injected to arrive at the evacuated region during maximum excursion or expulsion of the plasma electrons.
A beam-driven wake can be created by sending a relativistic proton or electron bunch into an appropriate plasma or gas. In some cases, the gas can be ionized by the electron bunch, so that the electron bunch both creates the plasma and the wake. This requires an electron bunch with relatively high charge and thus strong fields. The high fields of the electron bunch then push the plasma electrons out from the center, creating the wake.
Similar to a beam-driven wake, a laser pulse can be used to excite the plasma wake. As the pulse travels through the plasma, the electric field of the light separates the electrons and nucleons in the same way that an external field would.
If the fields are strong enough, all of the ionized plasma electrons can be removed from the center of the wake: this is known as the "blowout regime". Although the particles are not moving very quickly during this period, macroscopically it appears that a "bubble" of charge is moving through the plasma at close to the speed of light. The bubble is the region cleared of electrons that is thus positively charged, followed by the region where the electrons fall back into the center and is thus negatively charged. This leads to a small area of very strong potential gradient following the laser pulse.
In the linear regime, plasma electrons aren't completely removed from the center of the wake. In this case, the linear plasma wave equation can be applied. However, the wake appears very similar to the blowout regime, and the physics of acceleration is the same.

Wake created by an electron beam in a plasma

It is this "wakefield" that is used for particle acceleration. A particle injected into the plasma near the high-density area will experience an acceleration toward (or away) from it, an acceleration that continues as the wakefield travels through the column, until the particle eventually reaches the speed of the wakefield. Even higher energies can be reached by injecting the particle to travel across the face of the wakefield, much like a surfer can travel at speeds much higher than the wave they surf on by traveling across it. Accelerators designed to take advantage of this technique have been referred to colloquially as "surfatron"s.

Comparison with RF acceleration

The advantage of plasma acceleration is that its acceleration field can be much stronger than that of conventional radio-frequency (RF) accelerators. In RF accelerators, the field has an upper limit determined by the threshold for dielectric breakdown of the acceleration tube. This limits the amount of acceleration over any given area, requiring very long accelerators to reach high energies. In contrast, the maximum field in a plasma is defined by mechanical qualities and turbulence, but is generally several orders of magnitude stronger than with RF accelerators. It is hoped that a compact particle accelerator can be created based on plasma acceleration techniques or accelerators for much higher energy can be built, if long accelerators are realizable with an accelerating field of 10 GV/m.
Plasma acceleration is categorized into several types according to how the electron plasma wave is formed:

plasma wakefield acceleration (PWFA): The electron plasma wave is formed by an electron bunch
laser wakefield acceleration (LWFA): A laser pulse is introduced to form an electron plasma wave.
laser beat-wave acceleration (LBWA): The electron plasma wave arises based on different frequency generation of two laser pulses. The "Surfatron" is an improvement on this technique.^[9]
self-modulated laser wakefield acceleration (SMLWFA): The formation of an electron plasma wave is achieved by a laser pulse modulated by stimulated Raman forward scattering instability.

The first experimental demonstration of wakefield acceleration, which was performed with PWFA, was reported by a research group at Argonne National Laboratory in 1988.^[10]

Formula

The acceleration gradient for a linear plasma wave is:

E = c \cdot \sqrt{\frac{m_e \cdot \rho}{\varepsilon_0}}.

In this equation,

E

is the electric field,

c

is the speed of light in vacuum,

m_e

is the mass of the electron,

\rho

is the plasma density (in particles per cube metre), and

\varepsilon_0

is the permittivity of free space.

Dielectric wall accelerator

From Wikipedia, the free encyclopedia

Patent sketch for the DWA

A Dielectric Wall Accelerator (DWA) is a compact linear particle accelerator concept designed and patented^[1] in the late 1990s, that works by inducing a travelling electromagnetic wave in a tube which is constructed mostly from dielectric material. The main conceptual difference to a conventional disk-loaded linac system is given by the additional dielectric wall and the coupler construction.^{[clarification needed]}
Possible uses of this concept include its application in external beam radiotherapy (EBRT) using protons or ions.

Operation

An external alternating-current power supply provides an electromagnetic wave that is transmitted to the accelerator tube using a waveguide. The power supply is switched on only a very short time (pulsed operation).^[2]
Electromagnetic induction creates a traveling electric field, which accelerates charged particles. The traveling wave overlaps with the position of the charged particles, leading to their acceleration inside as they pass through the tube's vacuum channel.^[2] The field inside the tube is negative just ahead of the proton and positive just behind the proton. Because protons are positively charged, they accelerate toward the negative and away from the positive. The power supply switches the polarity of the sections, so they stay synchronized with the passing proton.

Construction

The accelerator tube is made from sheets of fused silica, only 250 µm thick. After polishing, the sheets are coated with 0.5 µm of chromium and 2.5 µm of gold. About 80 layers of the sheets are stacked together, and then heated in a brazing furnace, where they fuse together. The stacked assembly is then machined into a hollow cylinder. Fused silica is pure transparent quartz glass, a dielectric, which is why the machine is called a "dielectric wall accelerator."
A sketch of one of the assembled modules of the accelerator is shown in the patent sketch. The module is about 3 cm long, and the beam traveles upward. The dielectric wall is seen as item number 81. It is surrounded by a pulse forming device called a Blumlein. In figure 8A, the power supply charges the Blumlein. In figure 8B, silicon carbide switches surrounding the Blumlein close, shorting out the edge of the Blumlein. The energy stored in the Blumlein rushes toward the dielectric wall as a high voltage pulse.

Usage in Proton Therapy

The dose produced by a native and by a modified proton beam in passing through tissue, compared to the absorption of a photon beam

Particle beams such as protons and heavier ions offer improved dose distributions compared with the system known as intensity-modulated radiation therapy (IMRT).^[3] IMRT uses an indirect ionization of water in the cell to produce free radicals. These react chemically with the cell destroying single strands of the dual strand DNA.
Protons are many times heavier than electrons, which makes them easier to control and allows them to more precisely target a tumor. Protons are charged particles and are accelerated to a predetermined energy level which, using the bragg peak delivers the energy directly within 1–2 mm inside the tumor and stops. IMRT photons primarily indirectly ionizes the single strand DNA nuecleotide using the free radical method to disrupt cell life. Tumors are notorious for having a poor blood supply called cell (hypoxia). This requires the use of drugs to oxygenate the tumor. Since the tumor is fast growing it has a poor blood supply meaning any drugs directed at them will have difficulty getting to them.

Advantages and Limitations

The DWA addresses the main issues with the current proton therapy systems—cost and size Video. Depending on the desired final beam energy, the conventional medical accelerator solutions (cyclotrons and small synchrotrons) can have large cost factors and space requirements, which could be circumvented by DWAs. The cost estimate for a DWA is about 20 million US dollars.^{[citation needed]}
DWAs are expected to reach acceleration gradients around 100 MV/m.^[2]
The system is a spinoff of a DOE device to inspect nuclear weapons. This system requires several new advances because of the high energies, like e.g. high gradient insulators.^[4] A wide band-gap photoconductive switch, about 4,000 are needed. A Symmetric Blumlein, typical width 1mm.

Multi-gigaelectronvolt acceleration of positrons in a self-loaded plasma wakefield

Nature

524,

442–445

(27 August 2015)

doi:10.1038/nature14890

Received: 29 March 2015
Accepted: 30 June 2015
Published online: 26 August 2015

Electrical breakdown sets a limit on the kinetic energy that particles in a conventional radio-frequency accelerator can reach. New accelerator concepts must be developed to achieve higher energies and to make future particle colliders more compact and affordable. The plasma wakefield accelerator (PWFA) embodies one such concept, in which the electric field of a plasma wake excited by a bunch of charged particles (such as electrons) is used to accelerate a trailing bunch of particles. To apply plasma acceleration to electron–positron colliders, it is imperative that both the electrons and their antimatter counterpart, the positrons, are efficiently accelerated at high fields using plasmas¹. Although substantial progress has recently been reported on high-field, high-efficiency acceleration of electrons in a PWFA powered by an electron bunch², such an electron-driven wake is unsuitable for the acceleration and focusing of a positron bunch. Here we demonstrate a new regime of PWFAs where particles in the front of a single positron bunch transfer their energy to a substantial number of those in the rear of the same bunch by exciting a wakefield in the plasma. In the process, the accelerating field is altered—‘self-loaded’—so that about a billion positrons gain five gigaelectronvolts of energy with a narrow energy spread over a distance of just 1.3 metres. They extract about 30 per cent of the wake’s energy and form a spectrally distinct bunch with a root-mean-square energy spread as low as 1.8 per cent. This ability to transfer energy efficiently from the front to the rear within a single positron bunch makes the PWFA scheme very attractive as an energy booster to an electron–positron collider.