Wibbly-wobbly magnetic fusion stuff: The return of the stellarator

Are Technica describes a new kind of fusion reactor that's coming online. Wibbly-wobbly magnetic fusion stuff: The return of the stellarator "The heliac, the stellarator, and the tokamak are all trying to achieve the same thing: confine a plasma tightly in a magnetic bottle, tightly enough to push protons in close to each other. They all use a more-or-less donut shape, but that more-or-less involves some really important differences. That difference makes the stellarator a pretty special science and engineering challenge." Here's one of the magnets built to hold the field's shape:

The Thor: Ragnarok Trailer Gives Us an Excuse to Do Physics

Wired has a cute article, The Thor: Ragnarok Trailer Gives Us an Excuse to Do Physics analyzing the physics of the Thor/Hulk punch in the new trailer. They embed some simulations using two things I'd hadn't heard of before. The embedding of code seems to happen via trinket and the code is using GlowScript IDE to do the physics animation.

Science Articles

At first I misunderstood this Universe Today headline, Curiosity Captures Gravity Wave Shaped Clouds On Mars, to be about gravitational waves, but it's a more normal phenomenon they're seeing in studying Martian clouds from Curiosity. But I loved this line in the article:

But as Moore explained in an interview with Science Magazine, seeing an Earth-like phenomenon on Mars is consistent with what we’ve seen so far from Mars. ‘The Martian environment is the exotic wrapped in the familiar,’ he said. ‘The sunsets are blue, the dust devils enormous, the snowfall more like diamond dust, and the clouds are thinner than what we see on the Earth.’"

Universe Today also reported, Large Hadron Collider Discovers 5 New Gluelike Particles

According to the research paper, which appeared in arXiv on March 14th, 2017, the particles that were detected were excited states of what is known as a “Omega-c-zero” baryon. Like other particles of its kind, the Omega-c-zero is made up of three quarks – two of which are “strange” while the third is a “charm” quark. The existence of this baryon was confirmed in 1994. Since then, researchers at CERN have sought to determine if there were heavier versions.

And now, thanks to the LHCb experiment, it appears that they have found them. The key was to examine the trajectories and the energy left in the detector by particles in their final configuration and trace them back to their original state. Basically, Omega-c-zero particles decay via the strong force into another type of baryon (Xi-c-plus) and then via the weak force into protons, kaons, and pions.

From this, the researchers were able to determine that what they were seeing were Omega-c-zero particles at different energy states (i.e. of different sizes and masses). Expressed in megaelectronvolts (MeV), these particles have masses of 3000, 3050, 3066, 3090 and 3119 MeV, respectively. This discovery was rather unique, since it involved the detection of five higher energy states of a particle at the same time.

Extraterrestrial Origin Of Fast Radio Burst Phenomenon Confirmed:

Fast Radio Bursts (FRBs) have puzzled astronomers since they were first detected in 2007. These mysterious milliseconds-long blasts of radio waves appear to be coming from long distances, and have been attributed to various things such as alien signals or extraterrestrial propulsion systems, and more ‘mundane’ objects such as extragalactic neutron stars. Some scientists even suggested they were some type of ‘local’ source, such as atmospheric phenomena on Earth, tricking astronomers about their possible distant origins.

So far, less than two dozen FRBs have been detected in a decade. But now researchers from the Australian National University and Swinburne University of Technology have detected three of these mystery bursts in just six months using the interferometry capabilities of the Molonglo Observatory Synthesis Telescope (MOST) in Canberra, Australia. In doing so, they were able to confirm that these FRBs really do come from outer space.

Metallic hydrogen, once theory, becomes reality

Phys.org reports Metallic hydrogen, once theory, becomes reality. "The material - atomic metallic hydrogen - was created by Thomas D. Cabot Professor of the Natural Sciences Isaac Silvera and post-doctoral fellow Ranga Dias. In addition to helping scientists answer fundamental questions about the nature of matter, the material is theorized to have a wide range of applications, including as a room-temperature superconductor. The creation of the rare material is described in a January 26 paper published in Science."

It goes on to describe it's possible uses. The NY Times reports that there's some skepticism, Hydrogen Squeezed Into a Metal, Possibly Solid, Harvard Physicists Say. "But in the small but contentious field of high-pressure physics, some scientists who perform similar experiments were harshly skeptical and wondered how the research passed peer review at a top journal like Science."

There's been other reports of its creation but without looking into it much it's not clear to me if those were all debunked.

New method developed for producing some metals

MIT News reports New method developed for producing some metals "The MIT researchers were trying to develop a new battery, but it didn’t work out that way. Instead, thanks to an unexpected finding in their lab tests, what they discovered was a whole new way of producing the metal antimony — and potentially a new way of smelting other metals, as well."

Solar panels have gotten thinner than a human hair. Soon they’ll be everywhere.

Vox reports Solar panels have gotten thinner than a human hair. Soon they’ll be everywhere.

South Korean scientists have created solar PV cells that are 1 micrometer thick, hundreds of times thinner than most PV and half again as thin as other kinds of thin-film PV. (The research is in a paper just published in Applied Physics Letters.)

With cells this thin, solar PV can be integrated in all sorts of "wearables" — clothes, glasses, hats, or backpacks with solar cells integrated, continuously feeding power to our portable electronics. More to the point, PV could be integrated into just about anything.

Relativity Gets Thorough Vetting from LIGO

Frans Pretorius of the Princeton Physics Department writes Relativity Gets Thorough Vetting from LIGO.

The first thing that GW150914 can teach us is how closely nature follows Einstein’s prescriptions for colliding black holes. Researchers from the LIGO team and the Virgo team have performed a series of tests to see if any violations of general relativity might be lurking in the data of GW150914 [3]. They first determined the theoretical waveform, or ‘template,’ from general relativity simulations that best fit the measured signal (see Fig. 1). Their main finding is that the residual signal—obtained by subtracting this template from the data—is consistent with noise. This is, in a sense, the ‘everything’ test, as the template folds in all that general relativity predicts about the merger: the decay of the last few orbits of the two black holes, their violent collision and astonishingly rapid relaxation to a quiescent rotating black hole, the propagation of gravitational waves through the cosmos, and finally the transformation of these waves into a chirp in the LIGO detectors. Given the large signal-to-noise ratio of 24, the close agreement between the template and the data puts limits on alternative models. Specifically, the predictions of these models can only disagree with the general relativity prediction for GW150914 by, at most, 4%."

Has a Hungarian physics lab found a fifth force of nature?

Nature News reports Has a Hungarian physics lab found a fifth force of nature? "A laboratory experiment in Hungary has spotted an anomaly in radioactive decay that could be the signature of a previously unknown fifth fundamental force of nature, physicists say – if the finding holds up...Then, on 25 April, a group of US theoretical physicists brought the finding to wider attention by publishing its own analysis of the result on arXiv2. The theorists showed that the data didn’t conflict with any previous experiments – and concluded that it could be evidence for a fifth fundamental force."

The Hungarian team fired protons at thin targets of lithium-7, which created unstable beryllium-8 nuclei that then decayed and spat out pairs of electrons and positrons. According to the standard model, physicists should see that the number of observed pairs drops as the angle separating the trajectory of the electron and positron increases. But the team reported that at about 140º, the number of such emissions jumps — creating a ‘bump’ when the number of pairs are plotted against the angle — before dropping off again at higher angles.

Krasznahorkay says that the bump is strong evidence that a minute fraction of the unstable beryllium-8 nuclei shed their excess energy in the form of a new particle, which then decays into an electron–positron pair. He and his colleagues calculate the particle’s mass to be about 17 megaelectronvolts (MeV).

“We are very confident about our experimental results,” says Krasznahorkay. He says that the team has repeated its test several times in the past three years, and that it has eliminated every conceivable source of error. Assuming it has done so, then the odds of seeing such an extreme anomaly if there were nothing unusual going on are about 1 in 200 billion, the team says.

Feng and colleagues say that the 17-MeV particle is not a dark photon. After analysing the anomaly and looking for properties consistent with previous experimental results, they concluded that the particle could instead be a “protophobic X boson”. Such a particle would carry an extremely short-range force that acts over distances only several times the width of an atomic nucleus. And where a dark photon (like a conventional photon) would couple to electrons and protons, the new boson would couple to electrons and neutrons. Feng says that his group is currently investigating other kinds of particles that could explain the anomaly. But the protophobic boson is “the most straightforward possibility”, he says.

IBM's phase-change memory is faster than flash and more reliable than RAM

The Verge reports IBM's phase-change memory is faster than flash and more reliable than RAM

IBM today announced a more efficient way to use phase-change memory, a breakthrough that could help transition electronic devices from standard RAM and flash to a much faster and more reliable type of storage. Phase-change memory, or PCM, is a type of non-volatile optical storage that works by manipulating the behavior of chalcogenide glass, which is how data is stored on rewriteable Blue-ray discs. A electrical current is applied to change PCM cells from an amorphous to crystalline structure, allowing you to store 0s and 1s in either state while the application of low voltage can read the data back.

The issue in the past has been PCM's limited capacity and high cost; you can typically only store one 1 bit per cell. That makes it less useful for main memory applications like laptop or mobile phone storage. Yet IBM researchers discovered how to store 3 bits per cell by tinkering with how the crystals react to high temperatures, which are required to tap into multiple states for PCM cells. The jump is significant 'because at this density, the cost of PCM will be significantly less than DRAM and closer to flash,' Haris Pozidis, IBM's manager of non-volatile memory research, wrote in a statement."

Jazz Music and Physics Have a Lot More in Common Than You Think

Jazz Music and Physics Have a Lot More in Common Than You Think. I'm surprised.

It might not seem like music has much to do with cutting-edge physics at first glance. In his new book, The Jazz of Physics: The Secret Link Between Music and the Structure of the Universe, Brown University physics professor Stephon Alexander argues that using music as an analogy can shed light on some of the deepest mysteries in cosmology.

Alexander is not your typical physicist. Born in Trinidad and raised in the Bronx, he developed twin passions for jazz and physics at an early age. As a graduate student, he played the saxophone in jazz clubs and mastered Einstein’s equations. It’s a unique perspective that informs his approach to both; for instance, he views John Coltrane’s seminal Giant Steps album (1960), with its trademark ‘sheets of sound,’ as the ‘sonic equivalent to Einstein’s bending of the space-time fabric.’ Gizmodo caught up with Alexander to learn more about this hidden link.

CERN Just Dropped 300 Terabytes of Raw Collider Data to the Internet

CERN Just Dropped 300 Terabytes of Raw Collider Data to the Internet

‘Members of the CMS Collaboration put in lots of effort and thousands of person-hours each of service work in order to operate the CMS detector and collect these research data for our analysis,’ explains Kati Lassila-Perini, a CMS physicist who leads these data-preservation efforts. ‘However, once we’ve exhausted our exploration of the data, we see no reason not to make them available publicly. The benefits are numerous, from inspiring high-school students to the training of the particle physicists of tomorrow. And personally, as CMS’s data-preservation co-ordinator, this is a crucial part of ensuring the long-term availability of our research data.’

That's pretty cool.

The Best Explanation of LIGO I've Seen

Physicist Brian Greene was on Colbert this week and explained gravitational waves and how LIGO discovered them. It's pretty amazing TV. In just 8 minutes he explains it really clearly and entertainingly and gives a fantastic demo of laser interferometry.

LIGO

Last Friday I went to an MIT Panel on LIGO which was fascinating. Here are my notes.

Panel

• Moderator Rainer Weiss, Professor of Physics, Emeritus, invented laser interferometer gravitational wave detector, co-founded LIGO, also started COBE to detect Cosmic Microwave Background Radiation
• Lisa Barsotti, Principal Research Scientist,
• Edmund Bertschinger, Professor of Physics, theorist, cosmology and general relativity
• Matthew Evans, Assistant Professor of Physics,
• Salvatore Vitale, Research Scientist, data analysis, extracting signal from data

Rainer Weiss

• LIGO started in the 80s at MIT building 20, now gone
• No one cared about the old building so they could tear down walls, remove wiring, etc.
• Trucks on Vasser St shook building
• 1.5 meter prototype, two grad students
• F&T Deli in old Kendall Sq pre T stop. Ideas discussed at table there because they didn't kick you out. Now plaque there.
• Tons of students at all levels with all kinds of papers and thesis

Edmund Bertschinger

• If a tree falls and no one is there does it make a sound? No, because sound is waves hitting ear
• LIGO is the first direct signal from as close to a black hole as we will ever get
• To see this black hole would need a telescope that can resolve 10⁻²⁰ radians, 12 orders of magnitude smaller than we can
• Gravitational waves are oscillating tides traveling at the speed of light
• The distortion seen is like continents and oceans stretched from the moon tides
• LIGO built not to discover but as an observatory

Salvatore Vitale

• Animation, showed waves
• Different masses produced different signals
• Was 2 black holes of 30 solar masses each
• These were stellar black holes as opposed to those at the center of a galaxy (which would have been much more massive)
• The most massive black holes previously known which were not at center of a galaxy was half this size
• These black holes merged 1 billion years ago and weren't spinning that fast
• Mass tells us about the environment they were in
• Signal didn't deviate from General Relativity formulas
• 62 solar masses is result, 3 solar masses emitted in merger as gravitational waves in 0.2 seconds
• Sun has lost 0.03% of mass in last 5 billion years, so this was HUGE energy and yet it still took something as sensitive as LIGO to detect

Lisa Barsotti

• Amplitude of a gravitational wave (h) is 10⁻²¹
• L is length, so ΔL = h × L
• So try to use larger distances to see more movement, but still really small
• even if we could use the whole earth (L = 6,350km), that would require very precise measurements
• H atom is 10⁻¹⁰
• if L is 4km then it's 4x10⁻¹⁸ = proton diameter / 200
• it's crazy small we are superheroes
• One detector in Livingston, LA and one in Hanford, WA
• Each 4km tubes, 1.2m diameter, 10ms travel time between locations at c
• The more light you have you essentially amplify the wave
• Up to 125W entering interferometer, up to 1MW in each arm at full power (now operating at 100kW)
• Detector hears noise of interferometer + gravitational wave

Matthew Evans

• Three kinds of noise to be minimized and removed from signal:
  • Quantum Mechanics - Photons bouncing off mirror moves mirror makes noise, mainly high frequency noise
  • Thermal Noise - materials aren't at absolute zero, so brownian motion, lower frequency
  • Seismic Noise -, vibrations from outside world, lowest frequency

• incredible isolation, big scary laser, massive super optics
• 120 W laser
• roughly. 50 BBH merges each year I a volume of 1 Gpc³
• about 10 million galaxy's per Gpc³
• Advanced LIGO range now 0.1 - 1 Gpc depending on system mass
• We can expect 5 or more BBH events in next observing run (due later 2016)
• gravitational waves from Big Bang - frequency one over the age of the universe
• Future improvements:
  • Squeezed states of light to reduce quantum noise in the interferometer
  • Thermal noise reduced with better materials and cryogenics
  • Next big leap from a longer interferometer, up to 40km is doable, 400km is not

• Conclusions:
  • General Relativity is correct even in the strong field regime
  • Large stellar mass black holes exist in binaries and merge
  • Direct detection of gravitational waves is possible

Q&A

• Salvatore was first person to see the information come out of the data (the masses of the bodies)
• One location got the data 7ms ahead of the other and they're very proud of it
• Measuring amplitude so goes down with 1/distance, not 1/distance²
• Detector in Pisa Italy come online in 2016
• Another being built in Japan for 2017-2018
• Another copy of LIGO in India
• Not spherical waves. Technically quadropolar. Perpendicular to plane
• Just a sphere expanding won't create gravity waves, need things moving around each other to form a quadrupole system
• Though a lumpy supernova might
• Gravitational waves interact so weakly with matter, not absorbed by planets, etc.

Scientists Finally Detect Gravitational Waves

A hundred years ago Einstein predicted the existence of gravity waves rippling through space-time. They are the last prediction of relativity to go undetected and now have been observed.

The Verge has a nice overview article which includes a short video, Scientists have finally proven Einstein’s century-old theory about gravitational waves

The New Yorker has a more detailed article Gravitational Waves Exist: The Inside Story of How Scientists Finally Found Them. It includes some pictures of the instruments and prettier visualizations.

Weiss’s detection method was altogether different from Weber’s. His first insight was to make the observatory “L”-shaped. Picture two people lying on the floor, their heads touching, their bodies forming a right angle. When a gravitational wave passes through them, one person will grow taller while the other shrinks; a moment later, the opposite will happen. As the wave expands space-time in one direction, it necessarily compresses it in the other. Weiss’s instrument would gauge the difference between these two fluctuating lengths, and it would do so on a gigantic scale, using miles of steel tubing. “I wasn’t going to be detecting anything on my tabletop,” he said.

To achieve the necessary precision of measurement, Weiss suggested using light as a ruler. He imagined putting a laser in the crook of the “L.” It would send a beam down the length of each tube, which a mirror at the other end would reflect back. The speed of light in a vacuum is constant, so as long as the tubes were cleared of air and other particles the beams would recombine at the crook in synchrony—unless a gravitational wave happened to pass through. In that case, the distance between the mirrors and the laser would change slightly. Since one beam would now be covering a shorter distance than its twin, they would no longer be in lockstep by the time they got back. The greater the mismatch, the stronger the wave. Such an instrument would need to be thousands of times more sensitive than any previous device, and it would require delicate tuning in order to extract a signal of vanishing weakness from the planet’s omnipresent din.

“It never should have been built,” Isaacson told me. “It was a couple of maniacs running around, with no signal ever having been discovered, talking about pushing vacuum technology and laser technology and materials technology and seismic isolation and feedback systems orders of magnitude beyond the current state of the art, using materials that hadn’t been invented yet.”

It took years to make the most sensitive instrument in history insensitive to everything that is not a gravitational wave. Emptying the tubes of air demanded forty days of pumping. The result was one of the purest vacuums ever created on Earth, a trillionth as dense as the atmosphere at sea level. Still, the sources of interference were almost beyond reckoning—the motion of the wind in Hanford, or of the ocean in Livingston; imperfections in the laser light as a result of fluctuations in the power grid; the jittering of individual atoms within the mirrors; distant lightning storms. All can obscure or be mistaken for a gravitational wave, and each source had to be eliminated or controlled for. One of LIGO’s systems responds to minuscule seismic tremors by activating a damping system that pushes on the mirrors with exactly the right counterforce to keep them steady; another monitors for disruptive sounds from passing cars, airplanes, or wolves.

Some of the most painstaking work took place on the mirrors, which, Reitze said, are the best in the world “by far.” Each is a little more than a foot wide, weighs nearly ninety pounds, and is polished to within a hundred-millionth of an inch of a perfect sphere. (They cost almost half a million dollars apiece.) At first, the mirrors were suspended from loops of steel wire. For the upgrade, they were attached instead to a system of pendulums, which insulated them even further from seismic tremors. They dangle from fibres of fused silica—glass, basically—which, although strong enough to bear the weight of the mirrors, shatter at the slightest provocation. “We did have one incident where a screw fell and pinged one, and it just went poof,” Anamaria Effler, a former operations specialist at the Hanford site, told me. The advantage of the fibres is their purity, according to Jim Hough, of the University of Glasgow. “You know how, when you flick a whiskey glass, it will ring beautifully?” he asked. “Fused silica is even better than a whiskey glass—it is like plucking a string on a violin.” The note is so thin that it is possible for LIGO’s signal-processing software to screen it out—another source of interference eliminated.

So here's my favorite thing from the article. "Ultimately, he said, 'We accepted that the most economical explanation was that it really is a black-hole pair.'" That means that the most likely explanation of what their instruments were telling them is that a billion years ago two black holes merged and we're seeing the result now by measuring a laser bouncing off a mirror and seeing that it's a thousandth of a diameter of a proton off. Science is fucking amazing.

The importance is not just observing the theory. It's a new way for us to observe the universe. Until now, virtually everything has been seen via the electromagnetic force. Whether we use a visible light telescope or a radio telescope or spectrophotometer, those all basically detect photons moving at different frequencies. They are all part of one of the four physical forces. This is a direct measurement of gravity, a different force. Usually when we get a new instrument (the telescope, microscope, radio telescope, electron microscope, etc.) we get interesting new observations and unexpected science.

The LIGO scientists have extracted an astonishing amount from the signal, including the masses of the black holes that produced it, their orbital speed, and the precise moment at which their surfaces touched. They are substantially heavier than expected, a surprise that, if confirmed by future observations, may help to explain how the mysterious supermassive black holes at the heart of many galaxies are formed. The team has also been able to quantify what is known as the ringdown—the three bursts of energy that the new, larger black hole gave off as it became spherical. “Seeing the ringdown is spectacular,” Levin said. It offers confirmation of one of relativity theory’s most important predictions about black holes—namely, that they radiate away imperfections in the form of gravitational waves after they coalesce.

The detection also proves that Einstein was right about yet another aspect of the physical universe. Although his theory deals with gravity, it has primarily been tested in our solar system, a place with a notably weak gravitational regime. “You think Earth’s gravity is really something when you’re climbing the stairs,” Weiss said. “But, as far as physics goes, it is a pipsqueak, infinitesimal, tiny little effect.” Near a black hole, however, gravity becomes the strongest force in the universe, capable of tearing atoms apart. Einstein predicted as much in 1916, and the LIGO results suggest that his equations align almost perfectly with real-world observation. “How could he have ever known this?” Weiss asked. “I would love to present him with the data that I saw that morning, to see his face.”

Update: Here's a nice comic explanation of Gravitational Waves

Spooky Action at a Distance at Room Temperature

Physicists Can Now Achieve Quantum Entanglement at Room Temperature. "A team from the University of Chicago have demonstrated that it’s possible to entangle electrons at room temperature in a silicon carbide wafer. To do that, the team used infrared laser light to align the magnetic states of thousands of electrons in a 40 micrometer-cubed volume of the semiconductor, then applied magnetic pulses to entangle them."

2153 Nuclear Weapons Have Exploded On Earth

Kottke wrote: "2153! I had no idea there had been that much testing. According to Wikipedia, the number is 2119 tests, with most of those coming from the US (1032) and the USSR (727). The largest device ever detonated was Tsar Bomba, a 50-megaton hydrogen bomb set off in the atmosphere above an island in the Barents Sea in 1961. Tsar Bomba had more than three times the yield of the largest bomb tested by the US. The result was spectacular."

Orbital Mechanics made this:

The LHC Has Discovered a New Sub-Atomic Particle Called a Pentaquark

The LHC Has Discovered a New Sub-Atomic Particle Called a Pentaquark "For a long time, people have speculated that another class of quark ensemble, called the pentaquark, could in theory exist. The pentaquark is, perhaps unsurprisingly, supposed to be made up of five smaller entities—four quarks and an anti-quark. Now, for the first time, researchers working on the LHCb experiment at the Collider have found evidence for their existence."

The World's Biggest Physics Experiment Is About to Reboot

Gizmodo has a nice explainer on the LHC The World's Biggest Physics Experiment Is About to Reboot. They're gearing up for 13 TeV collisions by the end of May (up from 8 TeV in 2013). The article explains what they might find with these higher energy collisions.

Lockheed Martin Claims Sustainable Fusion Is Within Its Grasp

Lockheed Martin Claims Sustainable Fusion Is Within Its Grasp " Lockheed Martin's Skunk Works claims the ability to generate cheap energy from nuclear fusion with little waste or global warming is within its grasp."

Here they describe their Compact Fusion project. "Building on more than 60 years of fusion research, the Lockheed Martin Skunk Works approach to compact fusion is a high beta concept. This concept uses a high fraction of the magnetic field pressure, or all of its potential, so we can make our devices 10 times smaller than previous concepts. That means we can replace a device that must be housed in a large building with one that can fit on the back of a truck."

They think they can have a prototype working in 5 years, military applications in 10 and be powering the world in 20. If so, it's a completely new age for humanity.

The First Ever Photograph of Light as Both a Particle and Wave

The first ever photograph of light as both a particle and wave "Light behaves both as a particle and as a wave. Since the days of Einstein, scientists have been trying to directly observe both of these aspects of light at the same time. Now, scientists at EPFL have succeeded in capturing the first-ever snapshot of this dual behavior."