We Have Ignition!

So the big news of the week, which was preceded by the rumors a few days before the official announcement, is the breakeven achievement in a fusion process at Lawrence Livermore's National Ignition Facility (NIF).

This is certainly a major breakthrough, and it is something that has achieved for the very first time ever in a controlled experiment (it happens all the time in our Sun and other stars). However, to me, this is more of a proof-of-principle experiment, meaning that it is a demonstration that it is possible, rather than to show that it is viable. It is certainly very, VERY far away from producing anything useful because harnessing this energy is an entirely different matter.

While you can read many sites reporting this, I kinda like the one that I read on CNET because there's a certainly level of sensibility aimed towards the general public. In particular, there is this definition of what is meant by "breakeven":

More specifically, scientists at NIF kickstarted a fusion reaction using about 2 megajoules of energy to power the lasers and were able to get about 3 megajoules out. Based on the definition of ignition used by NIF, the benchmark has been passed during this one short pulse. 

But that doesn't convey the whole thing, because this is what should also be mentioned:

"The calculation of energy gain only considers the energy that hit the target, and not the [very large] energy consumption that goes into supporting the infrastructure," said Patrick Burr, a nuclear engineer at the University of New South Wales.

What it means is that they only considered the energy of the laser hitting the target, and then finding the energy output from the ignition that subsequently resulted in fusion. Sure, that energy output is greater than the input energy of the laser, but this is not the total energy of the entire facility that created the laser. That facility would still not be self-sufficient to run just by using the output energy of the fusion it created, even assuming 100% efficiency.

This does not diminish the amazing achievement, considering that other facilities and techniques have not even reach this level. It is just that it needs to be tampered with a bit more realistic expectations so that we don't oversell ourselves to the public.

Zz.

Muon g-2 Results Signify New Physics? Maybe Not.

The big news of the week that got all the media coverage is the result that came out of Fermilab's Muon g-2 experiment that confirmed an earlier result from Brookhaven more than a dozen years ago. Fermilab even announced it like.

However, as with any scientific discovery or announcement, one has to take a deep breath and let the process works itself out before we put our stamp of validity to it. This is because there is a theoretical calculation that has also been published along with this result that basically recalculates what the Standard Model predicts as the magnetic moment of a muon, and they found that the new calculation produces a result consistent with the experiment. In other words, there is no new physics if this calculation is verified, because the old Standard Model does, in fact, predicted this new result.

One of the major difficulties in physics is that in many situations, we do not have a simple equation that we can plug-and-chug to get numbers out. In fact, this is why predicting the weather is difficult, because the non-linear differential equations that need to be solved to get the number out can only be done numerically, i.e. it has to be done via some numerical algorithm.

This is made worse when there are a gazillion interactions involved in a system. So one ends up making simplifying models or adopt calculational techniques to allow us to get to some numerical answers. We benchmark the technique to known values and known systems to make sure that it gives accurate and sensible answers, but as we push the boundary even more, there is no guarantee that that calculational technique will work all the time.

The author of the theoretical paper used a calculational technique called lattice QCD. This is a known calculational model that has been described in simple terms in the link I provided above. It appears that using this method, the Standard Model does provide a value for the muon magnetic moment that is consistent with the experiment. If this is true, then it means that the old calculation of the magnetic moment was incorrect in the first place, and that there is discrepancy between what the Standard model predicts, and what the experiment measures.

While this is good news for the Standard Model and is another evidences of why it is an amazing theory, those who are looking for new physics beyond the Standard Model will obviously not be jumping for joy. But that isn't the issue here and not what I want to highlight. Rather, it is the constant reminder that in science, and especially in such exotic areas of physics, every discovery or new ideas must not be overblown or overhyped, because those require multiple verification over a period of time. It is not a situation for instant gratification. A lot of hard work is still to come because we have seen way too many times where something that was touted turned out to not be valid.

This announcement received a lot of media coverage. I just hope that this is a valid "new physics" and not just something that turned out to be what the old theory did predict.

Zz.

Possible Discovery Of A New Type of Tetraquark, And Possibly Misleading Reporting Article

We have had reports of the discovery of possible tetraquarks and pentaquarks before (i.e. particles with 4 quarks and particles with 5 quarks, respectively). There is an extensive overview of the experiment and theory in this article. So the announcement out of LHCb is not that new. What is new is that this could possibly be a new type of tetraquark made up of 4 heavy quarks.

“Particles made up of four quarks are already exotic, and the one we have just discovered is the first to be made up of four heavy quarks of the same type, specifically two charm quarks and two charm antiquarks,” says the outgoing spokesperson of the LHCb collaboration, Giovanni Passaleva. “Up until now, LHCb and other experiments had only observed tetraquarks with two heavy quarks at most and none with more than two quarks of the same type.”

You may read the preprint here.

That should clear up very much of what the brouhaha is. I probably would have glanced over this had it not be the fact that I stumbled onto another news reports of this discovery, but with a different tone that could be misleading.

First of all, let's look at how CERN produced its news release. The first paragraph read like this:

The LHCb collaboration has observed a type of four-quark particle never seen before. The discovery, presented at a recent seminar at CERN and described in a paper posted today on the arXiv preprint server, is likely to be the first of a previously undiscovered class of particles.

Notice that it says "... a type of four-quark particle ...". This means that there are already other four-quark particles, and that this discover is for a new type that has not been observed before.

Now, compare that to the reporting done by two (count 'em) particle physicists on The Conversation (a place that I go to regularly) on the same discovery. Here is what they wrote:

The LHCb collaboration at CERN has announced the discovery of a new exotic particle: a so-called “tetraquark”. The paper by more than 800 authors is yet to be evaluated by other scientists in a process called “peer review”, but has been presented at a seminar. It also meets the usual statistical threshold for claiming the discovery of a new particle.

If you don't know any better, by reading the first sentence alone, you'd think that this is the first ever discovery of a tetraquark, which would be false.

Certainly, if you read the article further, you'd come across the passage that clarifies what this discovery is:

All tetraquarks and pentaquarks that have been discovered so far contain two charm quarks, which are relatively heavy, and two or three light quarks – up, down or strange. This particular configuration is indeed the easiest to discover in experiments.

But the latest tetraquark discovered by LHCb, which has been dubbed X(6900), is composed of four charm quarks. Produced in high-energy proton collisions at the Large Hadron Collider, the new tetraquark was observed via its decay into pairs of well-known particles called J/psi mesons, each made of a charm quark and a charm antiquark. This makes it particularly interesting as it is not only composed entirely of heavy quarks, but also four quarks of the same kind – making it a unique specimen to test our understanding on how quarks bind together.

So this is not the first discovery of a tetraquark, but rather a discovery of a type of tetraquark, which is what the CERN article implied.

I know I'm being picky, but I've always said that communication between scientists and the general public is extremely tedious. Often times, what you wrote is not what they understood! And once something or some impression has stuck into their heads, it is very difficult to change that. Having a misleading idea immediately imprinted at the very beginning of an article is a horrible thing to do, even if the rest of the article is accurate. At worse, the reader holds on to the original misleading idea, and at best, the reader becomes confused with conflicting understanding. In the world where a lot of people have attention deficit and all they care about are quick bites of news, the message conveyed in the very first paragraph, or even the very first line, is all that they read and get.

Zz.

US National Academies Endorse Building Electron-Ion Collider

The US National Academy of Sciences, Engineering, and Medicine have endorsed the building of an electron-ion collider in the US as the top priority for the nuclear physics community. The detailed report on the building and science of such facility can be found here.

An EIC slams electrons into protons or heavier ions to investigate the quarks and gluons inside the nucleons. A collider with high energy and luminosity—a measure of the rate at which particle collisions occur—would have the fine resolution needed to answer some of the big-picture questions cited by the committee. Those include elucidating the origin of the mass and spin of nucleons, learning how gluons hold nuclei together, and determining whether emergent forms of matter made of dense gluons exist.

Beyond nuclear science, an EIC would benefit astrophysics, high-energy physics, accelerator physics, and theoretical and computational modeling, the committee writes. Further, it is the only high-energy accelerator (excluding light sources) being considered for construction in the nation, and building it would help to maintain US expertise in accelerator and collider science. “An EIC would be a unique facility in the world and would maintain US leadership in nuclear physics,” the report states. Although there is no existing EIC, China is also considering building one.

While this facility has the word "collider" attached to it, this is not a high-energy physics facility nor will it be funded out of the high-energy physics directorate of the DOE and NSF. It will be a nuclear physics facility, just like RHIC, CEBAF, and the upcoming FRIB.

Now, if only the politicians in Washington can be convinced of the need to build such a thing... y'know, make America "great" again, even though we no longer have any high-energy physics collider on US soil.

Zz.

Micro Fusion In Nanowires Array

This is a rather astounding result. The authors have managed to cause deuterons-deuterons fusion in an array of nanowires via igniting it using only joule-level pulsed laser[1], i.e. not using the huge, gigantic lasers such as that as the National Ignition Facility.

This is an open-access paper and you can get the full version at this link.

And no, before you jump all over this one and think that this is the next fusion power generator, you need to think again. The authors are touting this as a viable (and cheaper) ultra-fast pulsed neutron source, which can be useful in many applications and studies.

Zz.

[1] A. Curtis et al., Nature Communnications DOI: 10.1038/s41467-018-03445-

Atomic Age Began 75 Years Ago Today

December 2, 1942, to be exact.

This is an article on the history of the first controlled nuclear fission that was conducted at the University of Chicago 75 years ago that marked the beginning of the atomic/nuclear age.

They called this 20x6x25-foot setup Chicago Pile Number One, or CP-1 for short – and it was here they obtained world’s the first controlled nuclear chain reaction on December 2, 1942. A single random neutron was enough to start the chain reaction process once the physicists assembled CP-1. The first neutron would induce fission on a uranium nucleus, emitting a set of new neutrons. These secondary neutrons hit carbon nuclei in the graphite and slowed down. Then they’d run into other uranium nuclei and induce a second round of fission reactions, emit even more neutrons, and on and on. The cadmium control rods made sure the process wouldn’t continue indefinitely, because Fermi and his team could choose exactly how and where to insert them to control the chain reaction.

Sadly, other than a commemorative statue/plaque, there's not much left of this historic site. One of the outcome of this work is the creation of Argonne National Lab just outside of Chicago, where, I believe, the research on nuclear chain reaction continued at that time. Argonne now no longer carries any nuclear research work.

Zz.

RHIC Sees Another First

The quark-gluon plasma created at Brookhaven's Relativistic Heavy Ion Collider (RHIC) continues to produce a rich body of information. They have now announced that the quark-gluon plasma has produced the most rapidly-spinning fluid ever produced.

Collisions with heavy ions—typically gold or lead—put lots of protons and neutrons in a small volume with lots of energy. Under these conditions, the neat boundaries of those particles break down. For a brief instant, quarks and gluons mingle freely, creating a quark-gluon plasma. This state of matter has not been seen since an instant after the Big Bang, and it has plenty of unusual properties. "It has all sorts of superlatives," Ohio State physicist Mike Lisa told Ars. "It is the most easily flowing fluid in nature. It's highly explosive, much more than a supernova. It's hotter than any fluid that's known in nature."
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We can now add another superlative to the quark-gluon plasma's list of "mosts:" it can be the most rapidly spinning fluid we know of. Much of the study of the material has focused on the results of two heavy ions smacking each other head-on, since that puts the most energy into the resulting debris, and these collisions spit the most particles out. But in many collisions, the two ions don't hit each other head-on—they strike a more glancing blow.

It is a fascinating article, and you may read the significance of this study, especially in relation to how it informs us on certain aspect of QCD symmetry.

But if you know me, I never fail to try to point something out that is more general in nature, and something that the general public should take note of. I like this statement in the article very much, and I'd like to highlight it here:

But a logical "should" doesn't always equal a "does," so it's important to confirm that the resulting material is actually spinning. And that's a rather large technical challenge when you're talking about a glob of material roughly the same size as an atomic nucleus.

This is what truly distinguish science with other aspects of our lives. There are many instances, especially in politics, social policies, etc., where certain assertions are made and appear to be "obvious" or "logical", and yet, these are simply statements made without any valid evidence to support it. I can think of many ("Illegal immigrants taking away jobs", or "gay marriages undermines traditional marriages", etc...etc). Yet, no matter how "logical" these may appear to be, they are simply statements that are devoid of evidence to support them. Still, whenever they are uttered, many in the public accept them as FACTS or valid, without seeking or requiring evidence to support them. One may believe that "A should cause B", but DOES IT REALLY?

Luckily, this is NOT how it is done in science. No matter how obvious it is, or how verified something is, there are always new boundaries to push and a retesting of the ideas, even ones that are known to be true under certain conditions. And a set of experimental evidence is the ONLY standard that will settle and verify any assertion and statements.

This is why everyone should learn science, not just for the material, but to understand the methodology and technique. It is too bad they don't require politicians to have such skills.

Zz.

The Mystery Of The Proton Spin

If you are not familiar with the issues surrounding the origin of the proton's spin quantum number, then this article might help.

It explains the reason why we don't believe that the proton spin is due just to the 3 quarks that make up the proton, and in the process, you get an idea how complicated things can be inside a proton.

There are three good reasons that these three components might not add up so simply.

1. The quarks aren't free, but are bound together inside a small structure: the proton. Confining an object can shift its spin, and all three quarks are very much confined.
2. There are gluons inside, and gluons spin, too. The gluon spin can effectively "screen" the quark spin over the span of the proton, reducing its effects.
3. And finally, there are quantum effects that delocalize the quarks, preventing them from being in exactly one place like particles and requiring a more wave-like analysis. These effects can also reduce or alter the proton's overall spin.

Expect the same with a neutron.

Zz.

Spherical Tokamaks

Spherical tokamaks - can they beat out ITER to be the first to be a viable fusion generator?

This article describe the two separate efforts at using this technique in building such a facility, and it appears to not cost more than $10 billion and years of delay (yes, I'm looking at you, ITER!).

That's where the spherical tokamaks come in. The delightfully exotic term refers to a kind of device that can contain superheated plasma in powerful magnetic fields. These devices represent our species' best shot at generating those stellar temperatures we need to achieve nuclear fusion.

Right now, the two most advanced spherical tokamaks in the world are the National Spherical Torus Experiment-Upgrade (NSTX-U) at PPPL, and the Mega Ampere Spherical Tokamak (MAST) at the Culham Centre for Fusion Energy in the U.K.

At this stage, we need as many alternatives as we can afford. I'm glad we're not putting all our eggs in ITER, because I'm getting tired of it already.

Zz.

Proton Radius Problem

John Timmer on Ars Technica has written a wonderful article on the "proton radius problem". The article gives a brief background on an earlier discovery, and then moves on to a new result on a deuterium atom.

This area is definitely a work-in-progress, and almost as exciting as the neutrino mass deficiency mystery from a many years ago.

Zz.

ITER Is Getting More Expensive And More Delayed

This news report details the cost overruns and the more-and-a-decade delay of ITER.

ITER chief Bernard Bigot said the experimental fusion reactor under construction in Cadarache, France, would not see the first test of its super-heated plasma before 2025 and its first full-power fusion not before 2035.

The biggest lesson from this is how NOT to run a major international collaboration. Any more large science projects like this, and the politicians and the public will understandably be reluctant to support science projects of that scale. The rest of us will suffer for it.

Zz.

Wendelstein 7-X' Comes Online

ITER should look over its shoulder, because Germany's nuclear fusion reactor research facility is coming online. It is considerably smaller, significantly cheaper, but more importantly, it is built and ready to run!

Construction has already begun in southern France on ITER, a huge international research reactor that uses a strong electric current to trap plasma inside a doughnut-shaped device long enough for fusion to take place. The device, known as a tokamak, was conceived by Soviet physicists in the 1950s and is considered fairly easy to build, but extremely difficult to operate.

The team in Greifswald, a port city on Germany's Baltic coast, is focused on a rival technology invented by the American physicist Lyman Spitzer in 1950. Called a stellarator, the device has the same doughnut shape as a tokamak but uses a complicated system of magnetic coils instead of a current to achieve the same result.

Let the games begin!

Zz.

The Apparent Pentaquark Discovery - More Explanation

Recall the report on the apparent observation of a pentaquark made by LHCb a few weeks back. Fermilab's Don Lincoln had a video that explains a bit of what a quark is, what a pentaquark is, and how physics will proceed in verifying this.



Zz.

What Has Nuclear Physics Given Us?

I suppose I don't need to preach to the choir, but this is a nice, easy-to-read article if you ever encounter another person who is ignorant about how we have benefited from the study of nuclear physics.

A century is a long time in science, and things move quickly. It wasn’t long ago that we all had particle accelerators in our homes – the cathode ray tubes in our televisions. These have been superseded by LCD, LED and plasma displays, which are founded on our development of quantum technologies.

Perhaps the most prevalent application of particle accelerators today is in hospitals in the form of radiotherapy machines for the treatment of cancer.

In addition, Nuclear physics is the key to more or less all diagnostic imaging such as such X-ray, PET, CT, MRI, NMR, SPECT and other techniques that allow us to look inside the body without resorting to the knife.

If you’ve ever benefitted from one of these, thanks are due to many people, not least the nuclear physics pioneers who just wondered “what is this stuff?” and “what if…?”.

Certainly many aspects of nuclear physics overlaps with high-energy/particle physics, especially in the development of particle accelerators. But it is still worth noting that what started off as an area of study that had no obvious practical application has produced many indispensable necessities that are a part of our lives. This needs to be repeated many times for people  who simply do not see the value of basic, fundamental research.

Zz.

Pentaquark Discovery - Here We Go Again!

I read with a combination excitement and skepticism of the report that LHCb may have seen not one, but two pentaquarks. The skepticism should be justified because previous claims of the discovery of such quarks have turned out to be false. Still, this one comes with a 9sigma statistics.

The LHCb team is confident that the particles are indeed pentaquarks that comprise two up quarks, one down quark, one charm quark and one anticharm quark. "Benefitting from the large data set provided by the LHC, and the excellent precision of our detector, we have examined all possibilities for these signals, and conclude that they can only be explained by pentaquark states," explains LHCb physicist Tomasz Skwarnicki of Syracuse University in the US. 

As always, and as with any other new and important claim, time will tell as more analysis and experiments are done. The public and the media, especially, need to understand that this is still a work in progress, as with any scientific endeavor.

Zz.

Quark Gluon Plasma

The quark-gluon plasma (or fluid) that was observed at RHIC several years ago, is back in focus in this Don Lincoln's video.



So where do I get that t-shirt that he was wearing? :)

Zz.

A Tale Of Two Scientists

It is fascinating to read about the stuff behind the scene involving the negotiations between the United States and Iran regarding Iran's nuclear program. And in the middle of all this are two scientists/engineers out of MIT with nuclear science background.

At the Massachusetts Institute of Technology in the mid-1970s, Ernest J. Moniz was an up-and-coming nuclear scientist in search of tenure, and Ali Akbar Salehi, a brilliant Iranian graduate student, was finishing a dissertation on fast-neutron reactors.

The two did not know each other, but they followed similar paths once they left the campus: Mr. Moniz went on to become one of the nation’s most respected nuclear physicists and is now President Obama’s energy secretary. Mr. Salehi, who was part of the last wave of Iranians to conduct nuclear studies at America’s elite universities, returned to an Iran in revolution and rose to oversee the country’s nuclear program.

You may read more about it in the article. And I definitely agree with this sentiment:

Mr. Moniz, 70, understands his role well: He is providing not only technical expertise but also political cover for Mr. Kerry. If a so-called framework agreement is reached in the next few days, it will be Mr. Moniz who will have to vouch to a suspicious Congress, to Israel and to Arab allies that Iran would be incapable of assembling the raw material for a single nuclear weapon in less than a year.

“It wouldn’t mean much coming from Kerry,” said a member of the administration deeply involved in the strategy who spoke on the condition of anonymity. “The theory is that Ernie’s judgment on that matter is unassailable.”

At the heart of this is a scientific/technical issues. Now once presented, it is up to the politicians to decide, because beyond that, it is no longer a science/technical decision, but a political one. To have someone, a negotiator, who is not only knowledgeable in that area, but also who happens to be a world-renowned expert, is extremely beneficial.

Zz.

CERN's ALPHA Experiment

See, I like this. I like to highlight things that most of the general public simply don't know much about, especially when another major facility throws a huge shadow over it.

This article mentions two important things about CERN: It is more than just the LHC, and it highlights another very important experiment, the ALPHA experiment.

ALPHA’s main aim is to study the internal structure of the antihydrogen atom, and see if there exist any discernible differences within it that set it apart from regular hydrogen. In 2010 ALPHA was the first experiment to trap 38 antihydrogen atoms (an antielectron orbiting an antiproton) for about one-fifth of a second and then the team perfected its apparatus and technique to trap a total of 309 antihydrogen atoms for 1000 s in 2011. Hangst hopes that with the new updated ALPHA 2 device (which includes lasers for spectroscopy), the researchers will soon see precisely what lies within an antihydrogen atom by studying its spectrum. They had a very short test run of a few weeks with ALPHA 2 late last year, and will begin their next set of experiment in earnest in the coming months.

They will be producing more amazing results in the future, because this is all uncharted territory. 

Zz.

Lockheed Fusion "Breakthrough" - The Skeptics Are Out

Barely a day after Lockheed Martin announced their "fusion breakthrough" in designing a workable and compact fusion reactor, the skeptics are already weighing in their opinions even when details of Lockheed design has not been clearly described.

"The nuclear engineering clearly fails to be cost effective," Tom Jarboe told Business Insider in an email. Jarboe is a professor of aeronautics and astronautics, an adjunct professor in physics, and a researcher with the University of Washington's nuclear fusion experiment.
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"This design has two doughnuts and a shell so it will be more than four times as bad as a tokamak," Jarboe said, adding that, "Our concept [at the University of Washington] has no coils surrounded by plasma and solves the problem."

Like I said earlier, from the sketchy detail that I've read, they are using a familiar technique for confinement, etc., something that has been used and studied extensively before. So unless they are claiming to find something that almost everyone has overlooked, this claim of their will need to be very convincing for others to accept. As stated in the article, Lockheed hasn't published anything yet, and they probably won't until they get patent approval of their design. That is what a commercial entity will typically do when they want to protect their design and investment.

There's a lot more work left to do for this to be demonstrated.

Zz.

Lockheed Martin Claims Fusion Breakthrough

As always, we should reserve our judgement until we get this independently verified. Still, Lockheed Martin, out of the company's Skunk Works program (which was responsible for the Stealth technology), has made the astounding claim of potentially producing a working fusion reactor by 2017.

Tom McGuire, who heads the project, told Reuters that his team had been working on fusion energy at Lockheed’s Skunk Works program for the past four years, but decided to go public with the news now to recruit additional partners in industry and government to support their work.

Last year, while speaking at Google’s Solve for X program, Charles Chase , a research scientist at Skunk Works, described Lockheed’s effort to build a trailer-sized fusion power plant that turns cheap and plentiful hydrogen (deuterium and tritium) into helium plus enough energy to power a small city.

“It’s safe, it’s clean, and Lockheed is promising an operational unit by 2017 with assembly line production to follow, enabling everything from unlimited fresh water to engines that take spacecraft to Mars in one month instead of six,” Evan Ackerman wrote in a post about Chase’s Google talk on Dvice.

The thing that I don't have very clear is on the nature of the breakthrough that would allow them to do this, because what was written in the piece about using a magnetic bottle isn't new at all. This technique has been around for decades. I even saw one in the basement of the Engineering Research building at the University of Wisconsin-Madison back in the early 80's when they were doing extensive research work in this area. So what exactly did they do that they think will be successful that others over many years couldn't?

I guess that is a trade secret for them right now and we will just have to wait for the details to trickle out later.

Zz.