Hexbyte  Tech News  Wired Dark Matter Theorists Explore Axions as WIMPs Come up Short

Hexbyte Tech News Wired Dark Matter Theorists Explore Axions as WIMPs Come up Short

Hexbyte Tech News Wired

Physicists are remarkably frank: they don’t know what dark matter is made of.

“We’re all scratching our heads,” says physicist Reina Maruyama of Yale University.

“The gut feeling is that 80 percent of it is one thing, and 20 percent of it is something else,” says physicist Gray Rybka of the University of Washington. Why does he think this? It’s not because of science. “It’s a folk wisdom,” he says.

Peering through telescopes, researchers have found a deluge of evidence for dark matter. Galaxies, they’ve observed, rotate far faster than their visible mass allows. The established equations of gravity dictate that those galaxies should fall apart, like pieces of cake batter flinging off a spinning hand mixer. The prevailing thought is that some invisible material—dark matter—must be holding those galaxies together. Observations suggest that dark matter consists of diffuse material “sort of like a cotton ball,” says Maruyama, who co-leads a dark matter research collaboration called COSINE-100.

Jay Hyun Jo/DM-Ice/KIMS

Here on Earth, though, clues are scant. Given the speed that galaxies rotate, dark matter should make up 85 percent of the matter in the universe, including on our provincial little home planet. But only one experiment, a detector in Italy named DAMA, has ever registered compelling evidence of the stuff on Earth. “There have been hints in other experiments, but DAMA is the only one with robust signals,” says Maruyama, who is unaffiliated with the experiment. For two decades, DAMA has consistently measured a varying signal that peaks in June and dips in December. The signal suggests that dark matter hits Earth at different rates corresponding to its location in its orbit, which matches theoretical predictions.

But the search has yielded few other promising signals. This year, several detectors reported null findings. XENON1T, a collaboration whose detector is located in the same Italian lab as DAMA, announced they hadn’t found anything this May. Panda-X, a China-based experiment, published in July that they also hadn’t found anything. Even DAMA’s results have been called into question: In December, Maruyama’s team published that their detector, a South-Korea based DAMA replica made of some 200 pounds of sodium iodide crystal, failed to reproduce its Italian predecessor’s results.

These experiments are all designed to search for a specific dark matter candidate, a theorized class of particles known as Weakly Interacting Massive Particles, or WIMPs, that should be about a million times heavier than an electron. WIMPs have dominated dark matter research for years, and Miguel Zumalacárregui is tired of them. About a decade ago, when Zumalacárregui was still a PhD student, WIMP researchers were already promising an imminent discovery. “They’re just coming back empty-handed,” says Zumalacárregui, now an astrophysicist at the University of California, Berkeley.

He’s not the only one with WIMP fatigue. “In some ways, I grew tired of WIMPs long ago,” says Rybka. Rybka is co-leading an experiment that is pursuing another dark matter candidate: a dainty particle called an axion, roughly a billion times lighter than an electron and much lighter than the WIMP. In April, the Axion Dark Matter Experiment collaboration announced that they’d finally tweaked their detector to be sensitive enough to detect axions.

The detector acts sort of like an AM radio, says Rybka. A strong magnet inside the machine would convert incoming axions into radio waves, which the detector would then pick up. “Given that we don’t know the exact mass of the axion, we don’t know which frequency to tune to,” says Rybka. “So we slowly turn the knob while listening, and mostly we hear noise. But someday, hopefully, we’ll tune to the right frequency, and we’ll hear that pure tone.”

He is betting on axions because they would also resolve a piece of another long-standing puzzle in physics: exactly how quarks bind together to form atomic nuclei. “It seems too good to just be a coincidence, that this theory from nuclear physics happens to make the right amount of dark matter,” says Rybka.

As Rybka’s team sifts through earthly data for signs of axions, astrophysicists look to the skies for leads. In a paper published in October, Zumalacárregui and a colleague ruled out an old idea that dark matter was mostly made of black holes. They reached this conclusion by looking through two decades of supernovae observations. When a supernova passes behind a black hole, the black hole’s gravity bends the supernova’s light to make it appear brighter. The brighter the light, the more massive the black hole. So by tabulating the brightness of hundreds of supernovae, they calculated that black holes that are at least one-hundredth the size of the sun can account for up to 40 percent of dark matter, and no more.

“We’re at a point where our best theories seem to be breaking,” says astrophysicist Jamie Farnes of Oxford University. “We clearly need some kind of new idea. There’s something key we’re missing about how the universe is working.”

Farnes is trying to fill that void. In a paper published in December, he proposed that dark matter could be a weird fluid that moves toward you if you try to push it away. He created a simplistic simulation of the universe containing this fluid and found that it could potentially also explain why the universe is expanding, another long-standing mystery in physics. He is careful to point out that his ideas are speculative, and it is still unclear whether they are consistent with prior telescope observations and dark matter experiments.

WIMPs could still be dark matter as well, despite enthusiasm for new approaches. Maruyama’s Korean experiment has ruled out “the canonical, vanilla WIMP that most people talk about,” she says, but lesser-known WIMP cousins are still on the table.

It’s important to remember, as physicists clutch onto their favorite theories—regardless of how refreshing they are—that they need corroborating data. “The universe doesn’t care what is beautiful or elegant,” says Farnes. Nor does it care about what’s trendy. Guys, the universe might be really uncool.


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Does It Matter If China Beats the US to Build a 5G Network?

Does It Matter If China Beats the US to Build a 5G Network?

Technical standards for the next generation of wireless services aren’t even finalized, yet the US and China are already locked in a crucial race to be the first country to deploy a so-called 5G network.

Or at least that’s what both the US government and the wireless industry say. “The United States will not get a second chance to win the global 5G race,” Meredith Attwell Baker, president and CEO of the wireless industry group CTIA, warned in April, when the group released a report concluding that the US trails China and South Korea in preparing for 5G (fifth generation) networks. If that doesn’t change, the report warns, the US economy will suffer.

The report echoed a leaked National Security Council document that suggested the US government consider building a 5G network. If China dominates the telecommunications network industry, the document said, it “will win politically, economically, and militarily.”

Democrats are worried too. The Federal Communications Commission’s lone Democrat, Jessica Rosenworcel, penned an op-ed for TechCrunch earlier this year calling for a renewed 5G strategy to head off China.

The first specifications for the 5G standard were released last year, but the rest of the standard isn’t expected until later this month. Carriers don’t expect national availability in the US until 2020. The wireless industry promises that 5G will bring enormous boosts in speed and reliability to mobile devices, bridge the gap between wireline and wireless broadband speeds, and enable a new wave of technologies and applications that we can’t even imagine yet.

But why exactly is it so important for the US to build 5G networks before China? The benefits of 5G are obvious, but today the US doesn’t have the fastest home broadband speeds, nor the fastest or most widely available 4G networks, and often lags countries such as Finland, Japan, and South Korea in such metrics. Why would the US’s economic strength erode if it’s a bit late to the 5G party?

A widely cited 2016 report by consulting firm Accenture estimates that the construction and maintenance of 5G networks in the US could result in 3 million jobs and a $500 billion boost to GDP. But would all those jobs end up overseas if China is the first country with a nationwide 5G network?

Not necessarily says Sanjay Dhar, a managing director at Accenture who worked on the report. “Even if China wins the race to build various 5G technologies, it won’t be a zero-sum game,” he says.

Telecommunications industry analyst Jeff Kagan says the competition between the US and China keeps the US motivated to push 5G forward, but he doesn’t believe that it will make a big difference to the US economy in the long term if the US is second or third. “I don’t think it’s ever been more than a battle over the ego over which country is first,” he says.

For one thing, the two countries’ economies remain dependent on one another. Chinese telecommunications company ZTE nearly collapsed after the US barred American companies from selling components to it. Even if China “wins,” US companies will benefit by selling technology to China.

Roger Entner, a founder of Recon Analytics and coauthor of the CTIA report, concedes that it might not matter much if the US introduces 5G a few months later than China. Europe was quicker to roll out 2G, and Japan was the first with 3G, but that hardly deterred Apple and Google from dominating the smartphone market. But Entner argues that if China beats the US by a year or two, it could damage the US’s ability to compete in the global technology market.

3G, which began rolling out in the US in 2002, made possible the iPhone, which debuted in 2007, and the app market, which drove enormous investment in mobile computing, says mobile industry consultant Chetan Sharma. 4G, which made its commercial debut in the US in 2011, made smartphones and mobile apps even more appealing. Apps like Instagram, Uber, and Lyft were able to reach critical mass before competitors from other countries, giving the US an edge.

Ultimately, it’s the decisions of consumers and the private sector that determine the winners and losers in technology. The US “beat” Europe and Japan because Apple created a product that took smartphones mainstream, Google built a popular mobile operating system and gave it away for free, and Facebook built a platform that keeps people glued to their phones. The concern is that if China delivers widespread access to 5G first, its companies will get a head start on creating the next generation of high-tech products and services.

That’s less of a concern with smaller countries such as South Korea, Entner says, because Korean companies won’t have as large a market to test and refine ideas. But China’s 1.4 billion population provides the perfect place for a company to grow a business before exporting to other countries. Consider the WeChat instant messaging app, which offers mobile payments, online banking, car services, and more. Western companies have been trying to emulate its success and functionality for years. Huawei, now the world’s largest provider of telecommunications infrastructure equipment, initially grew by serving the domestic market.

Gaining a lead in 5G could have other benefits for Chinese tech as well. 5G enables not just increased speeds, but the increased capacity that could help support growth of the Internet of Things. All those connected cars and other gadgets will produce data. Lots of it. That could help put China ahead in cutting-edge developments, like self-driving cars and artificial intelligence. “The massive amounts of data that 5G will enable will also be critical for training AI algorithms,” says Paul Triolo, who focuses on technology for the political risk consulting firm Eurasia Group. “So being a leader in both developing equipment and applications will be a major economic advantage to the country or countries that seize the baton.”

Providing Wireless Spectrum

The odds of China beating the US by more than a year are real, Entner says, because the US hasn’t yet allocated enough wireless spectrum for the new networks. Thus far, most development of 5G technologies has focused on “millimeter wave spectrum,” a very high frequency range that enables extremely fast speeds, but only over a very short range. That would require carriers to deploy an enormous number of small cellular antennas to blanket the US with 5G.

Carriers are pushing the FCC to open more of what’s known as the midband of the spectrum for 5G, which would allow them to use large cell towers, much as they do now. That could make it faster to deploy 5G. The fear is that if enough of this midband spectrum isn’t made available to carriers, the 5G networks launched by the 2020 start date won’t actually cover the whole country. The FCC plans an auction to sell access to some of the midband spectrum to carriers in November, and last month it formally began the process to make another big chunk available.

But the longer this takes, the longer it will take US carriers to build real 5G networks. Entner says that in the US, it has historically taken years to launch the first networks after a new portion of spectrum has been identified for a particular use.

By contrast, the Chinese government has opened up more midband spectrum for use with 5G. That’s a big part of why the CTIA report suggests that China, along with South Korea, are “ahead” of the US.

National Security Concerns

Concerns about China’s lead in 5G spill into national security. Huawei’s products are now used by carriers around the world. But the US government has long worried that Huawei could help the Chinese government spy on US citizens, businesses, or political leaders. Huawei is effectively blocked from the US market. But if telecommunications equipment companies in the US and allied countries exit the market, US carriers might be left without any option.

Security experts say the government is right to be concerned. Although there would be serious political fallout if Huawei or another Chinese company were caught spying, equipment makers are in a position to deliberately build vulnerabilities into their products and hand the details of those problems to the Chinese government, says Ryan Kalember, senior vice president of cybersecurity strategy of the security company Proofpoint. Alternately, the companies could hand over the details of newly discovered security flaws to the Chinese government before fixing them.

US buyers will almost certainly continue to shun Huawei products in favor of equipment from US companies such as Cisco and Juniper, or Europe’s Ericsson and Nokia. But that won’t do much to challenge Huawei’s role globally.

Much the same can be said of the whole race to 5G. Even if the US wins the 5G race, it won’t stop China.


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Mind over matter? How fit you think you are versus actual fitness – Harvard Health Blog

Mind over matter? How fit you think you are versus actual fitness – Harvard Health Blog

Your mindset can impact your mortality in surprising ways.

The journal Health Psychology recently published a fascinating (and well-written) scientific study suggesting that how fit you think you are affects your risk of death more than how fit you actually are.

Here’s how researchers conducted the analysis

Researchers at Stanford University examined information collected by the National Center for Health Statistics (part of the Centers for Disease Control and Prevention) between 1990 and 2011. This included questionnaire responses, demographics, medical history, physical exam, and physical activity data from over 60,000 very diverse people — a representative sample estimated to reflect over 475 million US adults.

People were asked to rate how active they thought they were, as compared to their peers. The study volunteers’ actual activity was measured in three ways:

  • how often, how long, and how intensely they had participated in any of a long list of activities
  • movements measured by wearing an accelerometer for a week
  • how much physical labor their daily work included, either on the job or in their home.

Researchers took into account various measures of health. These included:

  • how healthy participants thought they were
  • any high-risk medical conditions (such as high blood pressure, diabetes, heart condition, stroke, and high cholesterol)
  • any disability
  • smoking status
  • body mass index
  • how many days over the past year they had been sick enough to be in bed
  • mental health (either a rating of how much stress they experienced, or if they had seen a mental health professional over the past year).

An impressively long list of demographic details were also accounted for, including: gender, age, race/ethnicity, marital status, education, environment (urban vs. rural), employment, annual household income, and access to medical care.

Lastly, the respondents’ data was linked to the National Death Index. Some respondents were followed for as many as 21 years; approximately 10% died during the study follow-up time.

Imagination may be as important as reality (maybe more)

The researchers analyzed the data in many different ways, including correcting for all these other important factors that could also influence their conclusions. The results were surprising. No matter how they ran the numbers, if people thought they were “a lot less active” than their peers, this was associated with a statistically significant higher risk of death: at least 18% when compared to the general population (those whose data were not included), and up to 71% higher when compared to people who thought they were “more active.” Again, this is regardless of actual physical activity or other health risk factors (smoking, being overweight, etc.).

Which is pretty remarkable.

The findings are supported by the previous research of one of the authors. She studied 84 women whose job (cleaning hotel rooms) was very active. Half of the women were informed that what they did for work was very active, active enough to meet recommended exercise levels. The other half got a lecture about physical activity and exercise recommendations, but no one told them that they were sufficiently active. Interestingly, after only four weeks, not only did the informed women report that they were more active, they also had decreases in weight, blood pressure, body fat, waist-to-hip ratio, and body mass index.

What could account for these findings?

The authors offer three explanations:

  1. Our mindset affects our motivation. If we feel like we’re active, then we’ll live that way, and vice versa.
  2. If we feel like we’re less active than everyone else, we feel stressed and depressed about it. Stress and depression are well known to be associated with poor health outcomes.
  3. The placebo effect. What we expect has a great influence, not only on how we feel, but a number of other measures. This is why a sugar pill can have a clinical response, or serious side effects. There is a mind-body connection that is real and powerful.

My take on this

Many doctors use negative language and feedback in their attempts to promote healthy behavior change. They’ll point out that the patient is overweight or inactive or smokes, and tell them how bad and dangerous their behavior is (i.e., “The Finger-Wagging Doc”). This research suggests that the opposite approach may be far, far more effective. After all, there are positive things to focus on for every patient. Maybe she has made a commitment to change, or he has had past successes that can be reviewed and studied. What has worked, and what can work? Highlight every positive behavior and small improvement, herald every success, and if it wasn’t sustained, emphasize that it’s all part of the learning curve. “The Health Coach Doc” approach may foster a lot more success, and better health.

Of note, this amazing study was conducted using data that is free and accessible to anyone. This is yet another reason we need to support government-funded scientific data collection and research.

Resources

Perceived Physical Activity and Mortality: Evidence from Three Nationally Representative US Samples. Health Psychology, July 2017.

Mind-Set Matters: Exercise and the Placebo Effect. Psychological Science, February 2007.

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