Quantum Cognition?

A lot of researchers and experts in other fields have tried to use various principles in physics in their own field. Economics have tried to invent something called Econophysics, to varying degree of success. And certainly many aspects of biology are starting to incorporate quantum effects.

Quantum mechanics has been used notoriously in many areas, including crackpottish application by the likes of Deepak Chopra etc. without really understanding the underlying physics. I don't know if this falls under the same category, but the news report out of The Atlantic doesn't do it any favor. I'm reading this article on quantum cognition, in which human behavior, and certain unpredictability and irrationality of human behavior, may be attributed to quantum effects!

Now, the reason why I don't think this article is that good is because it makes a number of either misleading, or strange errors.

Take, for example, the classic prisoner’s dilemma. Two criminals are offered the opportunity to rat each other out. If one rats, and the other doesn’t, the snitch goes free while the other serves a three-year sentence. If they both rat, they each get two years. If neither rats, they each get one year. If players always behaved in their own self-interest, they’d always rat. But research has shown that people often choose to cooperate.

Classical probability can’t explain this. If the first player knew for sure that the second was cooperating, it would make most sense to defect. If the first knew for sure that the second was defecting, it would also make most sense to defect. Since no matter what the other player is doing, it’s best to defect, then the first player should logically defect no matter what.

A quantum explanation for why player one might cooperate anyway would be that when one player is uncertain about what the other is doing, it’s like a Schrödinger’s cat situation. The other player has the potential to be cooperating and the potential to be defecting, at the same time, in the first player’s mind. Each of these possibilities is like a thought wave, Wang says. And as waves of all kinds (light, sound, water) are wont to do, they can interfere with each other. Depending on how they line up, the can cancel each other out to make a smaller wave, or build on each other to make a bigger one. If “the other guy’s going to cooperate” thought wave gets strengthened in a player’s mind, he might choose to cooperate too.

So you tell me if that made any sense or if this person has actually understood QM beyond what he read in a pop-science book. First of all, when wave cancellation occurs, it doesn't "make a smaller wave". It makes NO wave at that instant and time. Secondly, this person is espousing the existence of some kind of a "thought wave" that hasn't been verified, and somehow, the thought waves from the two different prisoners overlap each other (this, BTW, can be described via classical wave pictures, so why quantum picture in invoked here?).

But the fallacy comes in the claim that there is no other way to explain why different people act differently here without invoking quantum effects. Unlike physics systems where we can prepare two systems identically, we can find no such thing in human beings (even  with twins!). Two different people have different backgrounds and "baggage". We have different ethics, moral standards, etc. You'll never find two identical systems to test this out. That's why we have 9 judges on the US Supreme Court, and they can have wildly differing opinions on the identical issue! So why can't they use this to explain why people react differently under this same situation? Why can't they find the answer via the human psychology rather than invoking QM?

But it gets worse...

The act of answering a question can move people from wave to particle, from uncertainty to certainty. In quantum physics, the “observer effect” refers to how measuring the state of a particle can change the very state you’re trying to measure. In a similar way, asking someone a question about the state of her mind could very well change it. For example, if I’m telling a friend about a performance review I have coming up, and I’m not sure how I feel about it, if she asks me “Are you nervous?” that might get me thinking about all the reasons I should be nervous. I might not have been nervous before she asked me, but after the question, my answer might become, “Well, I am now!”

Of course, this smacks of the crackpottery done in "The Secret". Let's get this straight first of all, especially those who do not have a formal education in QM. There is no such thing as "wave-particle duality" in QM! QM/QFT etc. describe the system via a single, consistent formulation. We don't switch gears going from "wave" to "particle" and back to "wave" to describe things things. So the system doesn't move "from wave to particle", etc. It is the nature of the outcome that most people consider to be "wave-like" or "particle-like", but these are ALL produced by the same, single, consistent description!

The problem I have with this, and many other areas that tried to incorporate QM, is that they often start with the effects, and then say something like "Oh, it looks very much like a quantum effect". This is fine if there is an underlying, rigorous mathematical description, but often, there isn't! You cannot says that an idea is "complimentary" to another idea the same way position and momentum observables are non-commuting. The latter has a very set of rigorous mathematical rules and description. To argue that "... quantum models were able to predict order effects shown in 70 different national surveys... " is not very convincing because in physics, this would be quite unconvincing. It means that there are other factors that come in that are not predictable and can't be accounted for. What is there to argue that these other factors are also responsible for the outcome?

Again, the inability to test this out using identical systems makes it very difficult to be convincing. Human behavior can be irrational and unpredictable. That is know. Rather than considering this to be the result of quantum effects, why not consider this to be the result of a chaotic behavior over time, i.e. all of the various life experiences that an individual had all conspire to trigger the decision that he/she makes at a particular time. The "butterfly effect" in an individual's time line can easily cause a particular behavior at another time. To me, this is as valid of an explanation as any.

And that explanation is purely classical!

Zz.

A Physics App To Teach Physics

A group of educational researcher has created an app for iOS, Android, PCs, and Macs, that teaches physics to 9-graders.

The app, Exploring Physics, is meant to take particular physics curriculum already being taught in a number of public school districts, including Columbia's, and make it available digitally. The Exploring Physics curriculum app is designed to replace traditional lecture-based learning with discussions and hands-on experiments.

“The idea in the app is to have students learn by doing stuff,” said Meera Chandrasekhar, the co-creator of the app and a curators' teaching professor in the MU Department of Physics and Astronomy. “Even though it’s a digital app, it actually involves using quite a lot of hands-on materials.”

I haven't look at it. If any of you have, and better still, is using it, I very much like to hear your opinion.

Zz.

12-Year Old Girl Has More Sense Than The Media

I couldn't help it. When I saw a headline on CNN that said "British 12-year-old smarter than Einstein, Hawking", I had to look at this silliness. Turns out my initial guess was right. It was based on the outcome of some "intelligent test."

Lydia Sebastian achieved the top score of 162 on Mensa's Cattell III B paper, suggesting she has a higher IQ than well-known geniuses Albert Einstein and Stephen Hawking.

Now, lets dissect this just a bit, shall we (since I obviously have nothing better to do at this moment)? First of all, it has NOT been shown that such tests actually measure anything significant, much less, someone's "intelligence".  Secondly, how does one compare something to  something else that doesn't exist? Both Einstein and Hawking never took such tests, so who knows how well they would do. The article got away with this by "suggesting" that she has a higher IQ than those two people. That bullcrap!

Finally, such measure has nothing to do with one's ability to produce the same caliber of  work at Einstein and Hawking. In fact, even the 12-year old girl said as much:

The comparison doesn't sit well with the British student, who's currently in Year 8 at Colchester County high school, a selective girl's grammar school in Essex, England.

"I don't think I can be compared to such great intellectuals such as Albert Einstein and Stephen Hawking. They've achieved so much. I don't think it's right," Lydia told CNN.

You are so right, Lydia! Something isn't right, but somehow, the media didn't get this, even after you mentioned this to them! They are claiming that you are intelligent, and yet, they didn't pay attention to you when you told them that all this brouhaha isn't right.

We have at least shown one thing here. 12-year old Lydia has more intelligence and common sense than the media.

Zz.

Another Discovery of Weyl Fermions

We had an earlier report out of Science by the Princeton group on the discovery of the Weyl fermions in TaAs. This looks like another confirmation of that discovery on the same material using the same technique, out of a group in China.

In their experiments, Hasan and colleagues and Ding and colleagues used angle-resolved photoemission spectroscopy (ARPES) to detect the Fermi arcs, characteristic of Weyl nodes, on the surface of TaAs. ARPES is an ideal tool for such a purpose. The technique involves shining light on a surface and measuring the energy and momentum of ejected electrons. This allows for the explicit determination of both bulk nodes and the Fermi-arc surface states. Ding’s team used an interesting strategy to identify a Fermi arc and distinguish it from a more conventional closed Fermi surface (Fig. 1). They defined a closed contour in the momentum space spanned by their measurements and investigated how many times surface states at the Fermi energy crossed this contour. Such a contour will intersect a regular Fermi surface an even number of times. But it will intersect a Fermi arc an odd number of times if the arc encloses the projection of a Weyl point, thus providing a clean signature.

Click the link to get a copy of the actual paper.

Zz.

The Physics of BB-8 Star Wars Toy

Did you get caught up with the release of the new Star Wars toys and merchandise this past week?

It turns out that one of the toys, the BB-8, is quite astonishing. Rhett Allain has an interesting article on how this toy works.

The last part on inductive charging shouldn't be a puzzle anymore, should it? I've had a tea kettle for at least 6 years that used inductive heating. So inductive charging shouldn't be unusual anymore, I would think.

Still, like he said, this might be a toy that could be a very good physics class demo.

Zz.

Higgs Mass Refined

The combined data from ATLAS and CMS from LHC Run 1 has produced a Higgs mass with greater accuracy.

ATLAS reported the mass of this new boson to be in the mass region of 126 billion electronvolts, and CMS found it to be in the region of 125. In May 2015, the two experiments combined their measurements, refining the Higgs mass closer to 125.09 GeV.

But what is important is the report on the measurement of the coupling strength in the Higgs interactions.

This particular analysis focused on the interaction of the Higgs boson with other particles, known as coupling strength. The combined measurements are more precise than each experiment could accomplish alone, and results establish that the Higgs mechanism grants mass to both the matter and force-carrying particles as predicted by the Standard Model of particle physics.
.
.
In the Standard Model, how strongly the Higgs boson couples to another particle determines that particle’s mass and the rate at which a Higgs boson decays into other particles.
For instance, the Higgs boson couples strongly with the bottom quark and very weakly with the electron; therefore, the bottom quark has a much greater mass than the electron and the Higgs will commonly decay into a bottom quark and its antiquark.

This is why there is still a lot more to be measured and refined in Run 2.

Zz.

The History of Antiprotons

Antiprotons, the one-half of the particle used in the collision at the departed Tevatron at Fermilab, have had a long and distinguished history in the development of elementary particle physics. This CERN Courier article traces its history and all the important milestones in our knowledge due to the discovery of this particle.

Over the decades, antiprotons have become a standard tool for studies in particle physics; the word "antimatter" has entered into mainstream language; and antihydrogen is fast becoming a laboratory for investigations in fundamental physics. At CERN, the Antiproton Decelerator (AD) is now an important facility for studies in fundamental physics at low energies, which complement the investigations at the LHC’s high-energy frontier. This article looks back at some of the highlights in the studies of the antiworld at CERN, and takes a glimpse at what lies in store at the AD. 

Zz.

She's Still Radioactive!

She, as in Marie Curie.

This article examines what has happened to the personal effects of Marie Curie, the "Mother of Modern Physics".

Still, after more than 100 years, much of Curie's personal effects including her clothes, furniture, cookbooks, and laboratory notes remain contaminated by radiation, the Christian Science Monitor reports.

Regarded as national and scientific treasures, Curie's laboratory notebooks are stored in lead-lined boxes at France's national library in Paris.

While the library allows visitors to view Curie's manuscripts, all guests are expected to sign a liability waiver and wear protective gear as the items are contaminated with radium 226, which has a half-life of about 1,600 years, according to Christian Science Monitor.

What they didn't report, and this is where the devil-is-in-the-details part is missing, is what level of radioactivity is given off by these objects. You just don't want to sign something and not know the level you will be exposed to (which, btw, if you work in the US or at a US National Lab, a RWP (radiation work permit) must be posted at the door detailing the type of radiation and the level of radiation at a certain distance).

I suspect that this level is just slightly above background, and that's why they are isolated, but not large enough for concern. Still, the nit-picker in me would like to know such details!

Zz.

Quantum Teleportation Versus Star Trek's "Transporter".

Chad Orzel has an article on Forbes explaining a bit more on what quantum teleportation is, and how it is different than those transporters in Star Trek. You might think that this is rather well-known since this has been covered many times, even on this blog. But the ignorance of what quantum teleportation is still pops up frequently, and I see people on public forums still think that we can transport objects from one location to another because "quantum teleportation" has been verified.

So, if you are still cloudy on this topic, you might want to read that article.

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.

The Physics Of Air Conditioners

Ah, the convenience of having air conditioning. How many of us have thanked the technology that gave so much comfort during the hot, muggy day.

This CNET article covers the basic physics of air conditioners. Any undergraduate student who had taken intro Physics course should know the basic physics of this device when studying thermodynamics and the Carnot cycle. This is essentially a heat pump, where heat is transferred from a cooler reservoir to a warmer reservoir.

But, if you have forgotten about this, or if you are not aware of the physics behind that thing that gives you such comfort, then you might want to read it.

Zz.

Stnky Superconductor Breaks Record

No, I wasn't being deragoratory by calling it "stinky".

It turns out that hydrogen sulfide, the same compound that smells like rotten eggs, becomes a superconductor when solidified under pressure. And not only that, but it has recently be shown that it becomes a superconductor at a record highest transition temperature of 203.5 K.

Still, there are two points here that may make this not as "exciting" as one wold hope for. Earlier theoretical studies have predicted this to occur, and this material is expected to be a conventional superconductor mediated by phonons.

But the other issue, as in the practical aspect of this, may be even less enticing. This is because this material becomes a superconductor only under very high pressures.

The result may revive visions of superconductors that work at room temperature and magnetically levitated trains. But there's a catch: Hydrogen sulfide works its magic only when squeezed to more than 100 million times atmospheric pressure, roughly one-third as high as the pressure in Earth’s core. This condition makes it impractical for most applications. “Where does it go from here?” asks Igor Mazin, a theorist at the U.S. Naval Research Laboratory in Washington, D.C. “Probably nowhere.” Even so, the discovery is already altering the course of research in superconductivity.

So, while I think this is an exciting discovery, I'm not sure how much it will add to the physics and to applications..... yet.

Zz.

Record Number of Authors In Physics Paper - Follow Up

Remember just barely a couple of months ago, I mentioned about the brouhaha regarding the record number of authors in a combined CMS/ATLAS paper out of the LHC/CERN? In a Physics Today article, there's a bit more on this, especially on the possibly "light-hearted" nature of the Wall Street Journal article that first mentioned this.

As I've mentioned in the earlier entry, I don't quite know why this is such a freaking big deal. The experiments are getting to be more and more difficult, it requires a more complex instrument, and thus, require a lot more people. The fact that this paper actually combined the results from two HUGE collaboration should, as expected, results in a lengthy authors list. What is the big issue here?

Unfortunately, it gives the wrong impression to the rest of the public. The fact that areas such as condensed matter physics, which produces way, WAY more papers than high energy physics and usually tend to have a significantly small number of authors, somehow has been ignored (Phys. Rev. B, for example, which publishes papers in condensed matter/material  science, is produced TWICE a month, and each edition contains TWO volumes!). And yet, the exception here has been used as a rule for the entire field of physics! Where is the logic in that?

And for the record, I had published a paper in PRL, on an experimental work, no less, and the paper only had THREE authors. Count em'!

Zz.

The US's Silly Metric Phobia

There are certain things that make me just shake my head in disbelief. This is one such example.

I was reading this CNN article on why the United States is still one of the remaining 3 nations who have not adopted the SI units for everyday lives. The other two being Liberia and Myanmar (what does it say about the company you keep?). If there is such a thing about irrational beliefs and excuses, this would be front and center. In fact, I would even call them very stupid reasons.

The rest of the world calls Americans pennywise and pound foolish for still using a system that on its face makes little sense. And Americans, in turn, shun the metric system as a foreign creation. Never mind that Americans use the thermometer invented by Daniel Gabriel Fahrenheit, a foreigner of Dutch-German-Polish extract.

I want to know who are these airheads who are shunning something just because it is a "foreign creation". They say this, of course, while using devices made in China, and without realizing that "lbs, feet, inches, etc..." are British units of measure, the same people that the Americans chased out for their independence.

But I also want to talk to author Tom Wolfe (is he still alive?) and am curious if he still thinks this way:

In 1981, The New York Times reporter attended an anti-metric party at which Wolfe, in his customary white linen, judged a "Most Beautiful Foot" contest. 

''I hear that the meter is based on a rod somewhere outside of Paris,'' Wolfe said, according to the Times story. ''To use that as a basis for measurement is completely arbitrary and intellectual. I should say I have tremendous admiration for the French, but a matter of this importance should not be left to them. I like the idea of the foot - as a measurement in relation to the human body.'' 

This is utterly silly and irrational for two reasons:

1. He liked the idea that it is a measurement in relation to part of a body? Why? This is purely a personal preference, like having a favorite color. It is an example  of a ".. measurement that is completely arbitrary". There's no rational  reason to choose something JUST because it had a body-part connection. This is stupid!

2. Now that the "meter"  is now defined based on a physical constant and no longer that stick in Paris, is this sitting better now with him?

When the Nazi was in power, there was a concerted effort to discredit Einstein's theory of relativity (both  Special and General). In fact, there was even an effort to label it as "Jewish theory". So the argument was not based on any form of merit, but rather simply because of who same up with it. I'm surprised people  are not seeing similar parallel with the arguments above. How could these people, whom I presumed are intelligent people, made that kind of arguments and reasoning with a straight face?

Maybe this is another important factor of science education, since we tend to use SI units in science classes.

Zz.

Is There A Fundamental Difference In The Teaching of Physics and Chemistry/Biology?

I read in utter fascination of this opinion piece by Micheal McCracken. As you read this, pay attention not only to the fact that there appears to be a difference between how he perceived physics is taught at the undergraduate level, but also how the differences between the pedagogy of physics and chemistry/biology translates itself into how science is perceived by the public.

Abstract: During recent collaboration with colleagues to revise our institution's general-education curriculum, I encountered many perceptions of what we mean by the Natural Sciences. I was surprised to find that perceptions of scientific pedagogy varied significantly among the scientific disciplines, especially concerning issues of philosophy of science and epistemology, manifested in the approaches to teaching theoretical concepts and their development. These realizations suggest that Physics occupies a singular role in college curricula, introducing students, even at the introductory level, to the acquisition of knowledge by theoretical means and the assessment of theory based on experimental evidence.

His idea that fulfilling a student's requirement on learning Natural Science without taking physics and either chemistry or biology will be a serious deprivation on how science is done.

I tend to agree.

Zz.

Neutrino Week, In Summary

I mentioned the "Lost In Translation" problem of the Fermilab press release on the NOvA result. Jon Butterworth has a better article that describes clearly the NOvA result, and also includes the detection by IceCube of the highest energy neutrino ever recorded.

But I hate to say that I was more fascinated by his footnote:

¹Fermilab is in the Chicago suburb of Batavia. The neighbouring suburb is Geneva, Illinois. The means that the current and previous high-energy record-holding machines were built next to a Geneva. Rumours that part of China is to be renamed have just started.

Geneva, China?

Still, I wouldn't be surprise if China does go ahead on its own and build its own collider.

Zz.

NOvA Neutrinos - A Slight Lost In Translation

OK, this post is making two different points, and try not to miss both of them, because one of them reinforces my stand that what you say may not exactly be what they understood.

This press release out of Fermilab announced the observation of neutrino oscillation by the NOvA detectors. This is crucial for NOvA to show that they can detect what has already been shown to exist, because it is their mission to study this more carefully and to make specific measurements on this phenomenon.

That's my first point, and that's the main news. Now comes the second point. Another "news"  article took that Fermilab press release, and reported it. But read how it has been presented in the beginning.

Scientists have witnessed their first evidence of oscillating neutrinos, taking a huge step forward in particle physics. The new findings confirm that the extraordinary detector built for the project not only functions as planned but is also making great progress toward its goal of a major leap in our understanding of these particles.

Now this is important, because it comes in at the very beginning of the news article and it sets the tone for the entire report. But read it carefully. If you don't know any better, reading the first sentence will give you the impression that this is the first ever sighting of oscillating neutrinos! 
Since they got this from Fermilab's press release, did the press release itself made the same mistake? Let's take a look. The Fermilab's press release wrote this:

Scientists on the NOvA experiment saw their first evidence of oscillating neutrinos, confirming that the extraordinary detector built for the project not only functions as planned but is also making great progress toward its goal of a major leap in our understanding of these ghostly particles.

Notice the subtle but important difference. Fermilab's press release indicated that this is the first observation of neutrino oscilation by NOvA scientists! Of course, those of us in the know are aware that this statement is indicating that the new NOvA detector has detected what it SHOULD detect, and this is a major milestone in the commissioning of any new instrument, i.e. it should detect what have already been detected to make sure everything is working as it should. It doesn't mean that this neutrino oscillation is the first detection anywhere!

But this is what frequently happens. I don't know the quality of news reporting on "Science World Report", but that is irrelevant because this time of "mistranslation" happens regularly when non-experts tries to interpret or understand scientific reporting. It is why what you write needs to be looked at in several different angles and from background of people who are ignorant of not  only the subject matter, but also the progress in that area. A person reading the news report will think that this is the first ever evidence of neutrino oscillation, when that is clearly false.

The Fermilab news release should look at this type  of misreporting, and see if they need to make their press releases even more "simplified" so that people aren't mislead into thinking the same way as the news report. We must always be vigilant of the fact that what we wrote and what we meant may not be exactly what they understand.

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.

Do Students Know What They Know?

This is a rather interesting research on an effect that I was never aware of till now - the Dunning-Kruger effect. This is the effect where "... low-performing students tend to overestimate their abilities, while high-performing students estimate their abilities more accurately... "

The authors in this study compared their results from a physics course and a chemistry course, and came up with roughly the same effect.

Abstract: We have conducted an investigation into how well students in introductory science classes (both physics and chemistry) are able to predict which questions they will or will not be able to answer correctly on an upcoming assessment. An examination of the data at the level of students’ overall scores reveals results consistent with the Dunning-Kruger effect, in which low-performing students tend to overestimate their abilities, while high-performing students estimate their abilities more accurately. Similar results have been widely reported in the science education literature. Breaking results out by students’ responses to individual questions, however, reveals that students of all ability levels have difficulty distinguishing questions which they are able to answer correctly from those that they are not able to answer correctly. These results have implications for the future study and reporting of students’ metacognitive abilities.

(You should be able to get the paper for free)

Zz.

DES Sky Survey

I mentioned a while ago of the Dark Energy Survey project that is trying to map our universe and possibly produce a clearer picture of the dark energy phenomenon. This week we have one of the first mapping of our universe from DES, from just 3% of the DES data.

The DES dark matter map is not the first of its kind. Several pioneering analyses have come before it, most notably the Canada-France-Hawaii Telescope Lensing Survey, which used 4 times the number of distant galaxies that DES used to map an area of similar size but at higher resolution. The two teams have reached the same conclusions, though: The luminous matter that we can see is housed within the dark matter structures that we cannot see, and this dark matter forms a cosmic web of filaments, knots, and voids. As it continues collecting and analyzing data, DES will be able to map how these dark matter structures evolve over time.

There's a lot more to be discovered here as more of the data are analyzed.

Zz.

Report From 13 TeV

So far so good!

This report briefly describes the achievement of getting to 13 TeV collision energy at the LHC.

At 10.40 a.m. on 3 June, the LHC operators declared "stable beams" for the first time at a beam energy of 6.5 TeV. It was the signal for the LHC experiments to start taking physics data for Run 2, this time at a collision energy of 13 TeV – nearly double the 7 TeV with which Run 1 began in March 2010.

So far, they haven't been swallowed by a catastrophic black hole that is supposed to destroy our world. Darn it! What's next? Sighting of supersymmetry particles? You must be joking!

Zz.

Weyl Fermions

This is a bit late, but what they hey....

Here is another triumph out of condensed matter physics experiment. This is the first reported discovery of the Weyl fermions, first predicted and now found in a Tantalum arsenide compound.

Another solution of the Dirac equation – this time for massless particles – was derived in 1929 by the German mathematician Hermann Weyl. For some time it was thought that neutrinos were Weyl fermions, but now it looks almost certain that neutrinos have mass and are therefore not Weyl particles.

Now, a group headed by Zahid Hasan at Princeton University has found evidence that Weyl fermions exist as quasiparticles – collective excitations of electrons – in the semimetal tanatalum arsenide (TaAs).

For those who are keeping score, this means that these condensed matter systems have, so far, detected Majorana fermions, and analogous signatures of magnetic monopoles.

And many people still think condensed matter physics is all "applied" and not "fundamental"?

Zz.

The Standard Model Interactive Chart

Symmetry has published a webpage of an interactive chart for the Standard Model of elementary particle. It is almost like a periodic table, but with only the most basic, necessary information. A rather useful link when you need just the basic info.

Zz.

Yoichiro Nambu

This is a bit late, but I will kick myself if I don't acknowledge the passing of Yoichiro Nambu this past week. This person, if you've never heard of his name before, is truly a GIANT in physics, and not just in elementary particle. His work transcends any field of physics, and had a significant impact in condensed matter.

I wrote an entry on his work when he won the Nobel prize a few years ago. His legacy will live on long after him.

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.

Space Coffee

It's amazing how much physics and engineering go into just getting the ISS occupants to have their cup of Joe while on board the space station.



They should just open a Starbucks franchise up there. It would have been easier!

Zz.

More Physics Of Bicycles

I've already covered the topic on why a bicycle can be balanced easier when it is in motion many times in this blog. But here's another entry on this matter, this time it is a video from Minute Physics. Unfortunately, the explanation comes too rapidly for one to actually understand this simply by listening (you may have to play the video a few times).



Zz.

The Physics Of Your Vehicle Gas Mileage

While fuel prices are not as high as they were a few years ago, gas/petroleum cost is always a factor in our lives if we drive often.

This article reveals the physics of your vehicle gas mileage, and what may cause it to be better or worse than others. We can add this to another entry on this similar topic that I posted earlier.

Zz.

Don't Ask Siri To Divide 0/0

... unless you want a snarky remark about your personal life from her. You might get this response:

"Imagine that you have zero cookies and you split them evenly among zero friends. How many cookies does each person get? See? It doesn't make sense. And Cookie Monster is sad that there are no cookies, and you are sad that you have no friends."

Yowzah!

So, have you tried any other math questions with Siri and got similar amusing responses? Do share!

Zz.

100 Years Of General Theory of Relativity

This is a nice Nature Physics article summarizing the history of the General Theory of Relativity, especially on the historical verification of Einstein's idea.

If you have access to Nature Physics articles, you might also want to read the link in this paragraph:

Not everyone embraced the theory, though: in a Commentary on page 518 Milena Wazeck discusses the anti-relativist movement of the 1920s and uncovers an international network of opponents. Without any attempt at engaging in scientific argumentation, the refuters considered themselves “the last defenders of true physics”. Wazeck sees parallels with adversaries of Darwinism or anthropogenic climate change.

I suppose I shouldn't be surprised, but I continue to be amazed that human beings have such short memory, and how we continue to repeat the same things or the same mistakes that had been done before.

Zz.

4 Common Misconception About Quantum Physics

I've been critical of several physics article that have appeared in Epoch Times, many of them verging on crackpottery. But I have to admit, this one is actually quite good. It details 4 important misconception that came out of QM.

My summary of these misconceptions are:

1. Quantum entanglement transfers information faster than c.

2. Consciousness is necessary to "collapse" wave-function.

3. QM is only valid at the subatomic level.

4. Wave-particle "duality".

You may read the article to get the details, but for an article designed for the general public, it is actually quite accurate and understandable.

Zz.

Gravitational Lensing

Here's a simple intro to gravitational lensing, if you are not familiar with it.



Zz.

Quantum Superposition Destroyed By Gravitational Time Dilation?

This is another interesting take on why we see our world classically and not quantum mechanically. Gravitational time dilation is enough to destroy coherent states that maintain superposition.

With this premise, the team worked out that even the Earth's gravitational field is strong enough to cause decoherence in quite small objects across measurable timescales. The researchers calculated that an object that weighs a gram and exists in two quantum states, separated vertically by a thousandth of a millimetre, should decohere in around a millisecond. 

I think this is similar to Penrose's claim that gravity is responsible for decoherence of quantum states. It will be interesting if anyone can experimentally verify this latest theoretical finding.

Zz.

July Is The Least Popular Month For Physics

I did not know that!

The Buzz Blog at the APS Physics Central has a very interesting statistics on popularity of the word "physics" on Google search, and it showed a prominent pattern of large, yearly dip in July!

July is the least popular month for physics, marking the bottom of a decline that starts in May. This is not really surprising given that schools in the Northern Hemisphere tend to finish in May or June, and that July is the most popular month for vacations for Americans. Physics is definitely an academic term and it makes sense that its popularity aligns with students and researchers working to the academic calendar. Other academic terms such as "literature", "economics", and "math" also have minimum online interest during July. "Surfing", on the other hand, has a peak interest in July.

This means that right now, the date that this blog entry is posted, is the beginning of the downtrend. I won't blame you guys if the number of hits and read of this blog takes a strong dip starting now! :)

Zz.

How You Ask A Test Question May Impact A Student's Performance

When I first read this, I must say that I was not totally surprised by its results and conclusions.

This study was done on a group of female students at the University of Cambridge. In the study, they asked practically the same type of question, covering the same material, but in different ways. The students seem to do better when answering the questions when the "... questions are scaffolded...", i.e. it asked the students to answer one piece at a time, leading to the final answer (see the example in the paper. The paper is open access, so you should be able to get a copy of it.).

I find that one of the most common issues when students are given an entire problem in one shot is that they don't know where to start. They have all of these information swirling in their heads, and they don't know which one to use and applicable to answer the question. So having this "scaffolding", where the question asked for something obvious, and then lead the student to another level, certainly might help in guiding the student towards the final answer.

I remember my time as an undergrad at UW-Madison, taking an E&M class with Prof. Bernice Durand, that she had a unique form of assistance during her exams. She actually told us that if we got stuck, or can't answer a question, we could walk up to her during the exam, and asked for hints. Then, depending on the question, she might write something either as a hint, or something to start off. Depending on how much help she gave, the student won't get credit for knowing that part of the solution, but at least, might be able to continue and solve the rest of the problem. She told us that this way, both she and student can diagnose the source of the problem (i.e. say the student just didn't know where to start, but once that is solved, the student was able to carry out the rest of the solution),

I think this is a similar idea to this study. So as someone who benefited from this structure, I can understand how a student might do better when questions are framed like that.

Zz.

The Philosophy of the LHC

This is actually a nice article, and unlike other "confrontational" issues with regards to Physics and Philosophy, it addresses areas in which Philosophy can actually be of use in Physics, but not in the usual sense that have been tossed around.

There have been many tedious and futile discussions about the value of philosophy for modern science. I find it much more interesting and fruitful to ask if and in what way modern science can advance philosophy. The complexity, the new challenges and the new methods that arise in modern science in general - and at the LHC in particular - raise a number of questions that concern core issues of philosophy of science: what are the methods of acquiring knowledge, what is the role of models, and how does the intricate relationship between theory, computer simulations and experimental data work? The LHC has been built for fundamental physics, but it will also challenge and advance the philosophy, sociology and history of science!

We don't hear much about this aspect, mainly because it isn't "sexy". But this is a unique and useful convergence, and with physics opening up a myriad of discoveries that have changed our world view, there's nothing wrong with philosophy being guided by such discoveries.

Zz.

LHC at 13 TeV - Where Are The Crackpots Now?

I taunted the doomsday crackpots when the LHC hit 8 TeV a while back, and I'm going to taunt then again now. So where are these jokers hiding and what are their excuses for our world still had not been swallowed up by a gigantic blackhole created by the high-energy collisions?

Now granted that the last thing I want to do is hear any more nonsensical ramblings from these folks. They've take up too much oxygen already in their lifetimes. But still, I sometime wish I can come across one of them, and really, REALLY, ask them if they think that they have a huge egg on their faces. There is just not enough follow-up on things like this, and I often wonder if these people actually learned something from their silliness, or if they are still delusional and stubborn about it.

At some level, the same can be said about all those preprints and theories that came out when OPERA reported faster-than-light neutrinos. I sometime wish I could talk to these people, who I don't consider to be crackpots, but who should know better than to jump the gun. I always wanted to know why they publish their theories THAT quickly to jump on the bandwagon. Is it the idea of wanting to be the first? Is it the concept of throwing out as many darts as one can and hope that one will stick? How do they feel now that they somehow came up with a theory based on a non-existing evidence?

So many questions, and so little time to find out the answers.

Zz.

Why Do We Plot Our Data?

I stumble upon this Rhett Allain's article on Wired on the importance of plotting data, especially in experiments, and it reminded me of a similar document that had been used for quite a while at the Illinois Institute of Technology for their undergraduate physics labs.

I think both of them had the same idea and the same emphasis. Graphing and being able to know how to use it to analyze data is something that isn't normally taught in a physics class, and that is a shame, because it is an essential part of connecting experimental data to a "theory" or theoretical model. This is where the experiment and the theory meet! It is also where we can analyze how "reliable" or how much confidence we have on what we measure. This is important because when we do not have 100% certainty, we need to know when something is good enough to be accepted.

These are skills and knowledge that many are not exposed to, and it is sad that science classes, especially those involved with experiments, do not put more emphasis on such things.

Zz.

Leon Lederman. Sold His Nobel Prize Medal

i find that it is sad that he had to resort to this.

Retired experimental physicist Leon Lederman is now 92 years old and facing serious health problems and memory loss. So he took to an online auction and sold his 1988 Nobel prize for his co-discovery of subatomic particle called the muon neutrino to cover his costs. The price of Nobel fame online? $765,002.

It had been only a few years ago that I mentioned about his efforts on the streets of Chicago to educate the public about physics. I wish more could have done to help him to not have him sell his medal.

Zz.

Wheeler's "Delayed Choice" Experiment Done With Single Atoms

Looks like we now have the first "Delayed Choice" experiment done with single atoms, this one with single He atoms.

Indeed, the results of both Truscott and Aspect's experiments shows that a particle's wave or particle nature is most likely undefined until a measurement is made. The other less likely option would be that of backward causation – that the particle somehow has information from the future – but this involves sending a message faster than light, which is forbidden by the rules of relativity.

There are now many experiments that support QM's non-realism and quantum contextuality. This latest experiment adds to the body of evidence.

Zz.

The NSLS II

CERN Courier has a rather informative article on the start-up of NSLS II and its capabilities. It certainly is the newest "from scratch" light source facility (rather than just an upgrade of an existing facility).

I hope they save some parts of the original NSLS and commemorate it with some sort of a marker. After more than 30 years of service, that facility certainly was worth every penny spent on it.

Zz.

What Is Really "Real" In Quantum Physics

This is an excellent article from this week's Nature. It gives you a summary of some of the outstanding issues in Quantum Physics that are actively being looked into. Many of these things are fundamental questions of the interpretation of quantum physics, and it is being done not simply via a philosophical discussion, but via experimental investigation. I do not know how long this article will be available to the public, so read it now quickly.

One of the best part about this article is that it clearly defines some of the philosophical terminologies in term of how they are perceived in physics. You get to understand the meanings of "psi-epistemic models" and "psi-ontic models", and the differences between them and how they can be distinguished in experiments.

But this is where the debate gets stuck. Which of quantum theory's many interpretations — if any — is correct? That is a tough question to answer experimentally, because the differences between the models are subtle: to be viable, they have to predict essentially the same quantum phenomena as the very successful Copenhagen interpretation. Andrew White, a physicist at the University of Queensland, says that for most of his 20-year career in quantum technologies “the problem was like a giant smooth mountain with no footholds, no way to attack it”.

That changed in 2011, with the publication of a theorem about quantum measurements that seemed to rule out the wavefunction-as-ignorance models. On closer inspection, however, the theorem turned out to leave enough wiggle room for them to survive. Nonetheless, it inspired physicists to think seriously about ways to settle the debate by actually testing the reality of the wavefunction. Maroney had already devised an experiment that should work in principle, and he and others soon found ways to make it work in practice. The experiment was carried out last year by Fedrizzi, White and others.

There is even a discussion on devising a test for Pilot wave model after the astounding demonstration of the concept using simple classical wave experiment.

Zz.

Review of Leonard Mlodinow's "Upright Tinkers"

This is a review of physicist's Leonard Mlodinow's new book "Upright Tinkers: : The Human Journey from Living in Trees to Understanding the Cosmos."

In it, he debunks the myths about famous scientists and how major discoveries and ideas came about.

With it, he hopes to correct the record on a number of counts. For instance, in order to hash out his theory of evolution, Darwin spent years post-Galapagos shifting through research and churning out nearly 700 pages on barnacles before his big idea began to emerge. Rather than divine inspiration, Mlodinow says, achieving real innovation takes true grit, and a willingness to court failure, a lesson we’d all be wise to heed.

“People use science in their daily lives all the time whether or not its what we think of as ‘science,’” he continues. “Data comes in that you have to understand. Life’s not simple. It require patience to solve problems, and I think science can teach you that if you know what it really is.”

Scientists would agree. Recently, psychologist Angela Duckworth has begun overturning fundamental conventional wisdom about the role intelligence plays in our life trajectories with research illustrating that, no matter the arena, it’s often not the smartest kids in the room who become the most successful; it’s the most determined ones.

As I've said many times on here, there is a lot of value in learning science, even for non-scientists, IF there is a conscious effort to reveal and convey the process of analytic, systematic thinking. We all live in a world where we try to find correlations among many things, and then try to figure out the cause-and-effect. This is the only way we make sense of our surrounding, and how we acquire knowledge of things. Science allows us to teach this skill to students, and letting them be aware of how we consider something to be valid.

This is what is sadly lacking today, especially in the world of politics and social policies.

Zz.

Record Number of Authors In Physics Paper

I don't know why this has been making the news reports a lot since last week. I suppose it must be a landmark even or something.

The latest paper on the Higgs is making the news, not for its results, but for setting the record for the largest number of authors on a paper, 5154 of them.

Only the first nine pages in the 33-page article, published on 14 May in Physical Review Letters, describe the research itself — including references. The other 24 pages list the authors and their institutions.

The article is the first joint paper from the two teams that operate ATLAS and CMS, two massive detectors at the Large Hadron Collider (LHC) at CERN, Europe’s particle-physics lab near Geneva, Switzerland. Each team is a sprawling collaboration involving researchers from dozens of institutions and countries.

And oh yeah, they reduced the uncertainty in the Higgs mass to 0.25%, but who cares about that!

This is neither interesting nor surprising to me. The number of collaborators in each of the ATLAS and CMS detector is already huge by themselves. So when they pool together their results and analysis, it isn't surprising that this happens.

Call me silly, but what I was more surprised with, and it is more unexpected, is that the research article itself is "nine pages". I thought PRL always limits its papers to only 4 pages!

BTW, this paper is available for free under the Creative Commons License, you may read it for yourself.

Zz.

Electron Pairing Without Superconductivity

The interesting news from last week is the publication in Nature of the confirmation of the presence of electron pairs in STO, but without superconductivity.

This is significant because this has always been a possibility, i.e. where the electrons pair up but do not form any long range order or become a condensate. This phenomenon was hinted at in the cuprate superconductors especially in the underdoped regime where experiments such as tunneling and ARPES have shown the presence of a gap, called the pseudogap, above the critical temperature Tc. Whether this pseudogap is the precursor to the electrons having long-range order and condenses below Tc, or whether these electrons are actually competing with those that do, is still a highly debated question.

My guess is that this paper will be a significant piece of information to that puzzle.

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.

The Birth of Soft Condensed Matter Physics

This is a very nice article to introduce to you the field of Soft Condensed Matter Physics as a way to celebrate the life of physicist Sam Edwards, who passed away recently.

Zz.

Teacher Arrested After Burning Message On Kids Arms Using Tesla Coil

Really!

I read this, and I don't know what to make of this. It appears that the parents who filed the complaint against this teacher are making a bigger deal out of it than the students themselves.

Samuel Dufner thought he'd liven up a science class at South Salem High School in Oregon. So, as the Associated Press reports, he explained to the kids last Thursday that a Tesla coil could actually burn a mark on their skin.

And it was a "I Love Mom" message too, because Mother's Day is coming up. Awww.....

But obviously, a parent didn't think it was that warm and fuzzy, because the parent filed a complaint and the teacher was arrested for "criminal mistreatment". Still, the report indicated that no charges has been filed.

The kids thought it was fun, and it didn't hurt. Were any animals or human being harmed in this experiment?

Zz.

The Physics Of Tesla Home Battery

Elon Musk is at it again.

Rhett Allain has a nice article giving you some of the background physics you need to evaluate the effectiveness of the new Tesla's Powerwall home battery unit.

I would get this if it can be sustained for a full day with a single, full charge. So now I have to figure out how much my computers, entertainment system, freezer, refrigerators, and my central air system need! :)

Zz.

Particle Accelerators - Current And Future Applications

Another example of where accelerators have wide-ranging applications outside of just high energy physics experiments.



Zz.

The Difference Between Cats And Dogs

I'm sure many of you have noticed this, but have you sat down and really analyze it? Or maybe in my case, over-analyzing it?

A bunch of friends and I were sitting around and just talk (y'know, the stuff you do face-to-face and doesn't involve moving your fingers over a virtual keyboard). Of course, the conversation went over various topics of politics, the economy, etc...etc. At some point, it inevitably meandered into science, and physics in particular, since everyone there knew I am a physicist. It was when we got to that point that I noticed how the nature of the conversation changed.

We were comfortable with just talking when we were discussing politics, etc. But when we got to physics, we had to bring out several sheets of paper and started to either do sketches, or in my case, having to write simple, basic equations and numbers. This shouldn't be surprising because sketching something in physics is often the simplest and most direct way to demonstrate or explain something. We physicists, engineers, and other scientists tend to grab almost anything we can get (napkins, crumpled papers, etc.) when we sit and talk about what we do. Even in school, the way different subjects are taught can be evident. I remember being in a literature class where the instructor barely wrote anything on the board. This is unheard of in a math, physics, etc. class where it is not uncommon for the instructor to need several boards, or had to erase the one board over and over again throughout an entire class session.

I can't help thinking that, among other things, this signifies clearly the differences between one type of discipline versus another. While certain the field of economics, politics, etc. have more exact components, it is interesting that we all find that we can simply just talk verbally about it to get out point across... or can we? On the other hand, a STEM subject often requires illustrations, rudimentary calculations, etc. when we discuss things. I certainly find it significantly easier with a pen and paper to illustrate various topics that are being discussed.

So that led me to consider why that is so. Is it because there's a lot more "ambiguity" when we discuss politics and economics and other social matters? Are they more qualitative in nature? Is the discussion of STEM subject more well-defined and more quantitative? One example I have is the a topic of discussion that we had about politics and the issue of cutting taxes. This is a popular topic when there is an election coming. It takes no knowledge of anything to say that one wants to cut taxes. Yet, the issue of "by how much" and "how did you arrive at that figure" very seldom enters into any form of public discussion. It is as of the public is either incapable of understanding the details of such issue, or they don't have the patience to pay attention into such boring stuff.

We all want to pay less taxes! Who wouldn't? But we also depend on many services provided by various parts of the government, be it local or federal. One should not just say one is going to cut taxes, because frankly, saying just that, to me, is idiotic! One can cut it by $1 and that would have been a tax cut. Rather, I want to hear answers to : (1) by how much are you going to cut such-and-such taxes (2) how did you come up with that number (3) what were your assumptions that you used to arrive at that number (i.e. you must have made some estimates on what it would cost to provide the necessary services, and how much revenue you'd exact to make in that fiscal year)? etc.. etc. In other words, there are PLENTY of details that has to be revealed beyond just saying that you want to cut taxes. Otherwise, that statement is really empty and meaningless, and might even be totally irrelevant.

But this is usually missing from many political discussions, and it may even be something that the public simply don't care to hear, especially if they can be seduced by just sound bites. A lot of discussion in this area are often simply statements made without a lot of justification, and even if there were, they were mainly anecdotes. To me, this is why discussion on such topics can often be done verbally, because they are mainly "abstract", qualitative ideas (i.e. what goes up, must come down) without diving into the details (i.e. when and where it comes down).

But then you could turn around and ask me "But ZapperZ, isn't this how science articles and news are also done? I seldom seen pictures or number to explain the science that is being reported."

That is true, but that is because scientists and science writers (who are often not scientists themselves) have learned to communicate more effectively with the public, i.e. we can't bore then with the details and the numbers if we want to get their attention. Instead, we have to use bells and whistles, and we must be perky and superficial. But in my case, I find that being superficial and qualitative were sufficient in my discussion on political and social matters, but it wasn't sufficient when I had to answer a question on why centrifugal force is a "fictitious force". In fact, I had to get up from my chair and had to illustrate certain things by acting it to be able to get the message across. I didn't have to do anything close to that to discuss the latest local election in my area.

So maybe there is an inherent differences in these two board areas that can't be changed or eliminated, very much like dogs and cats. But I've seen dogs and cats get along very well and learn from each other. And certainly while those in STEM areas are learning how to communicate better to the public, and those in politics, economics, and social science are applying more quantitative aspects to their studies, are the public aware of such differences and how they could learn from it to look internally on how they analyze and conclude something? Have they looked at the differences between dogs and cats deeply enough beyond just the superficial level?

I don't know.

Zz.

IceCube Neutrinos Are Truly Cosmic

Latest data analysis from IceCube concludes that the neutrinos that had been reported are consistent with them having a cosmic origin.

Two groups have now analyzed a larger data set (covering years 2010 to 2013). The first work, conducted by the IceCube collaboration, identifies a total of 137 high-energy neutrinos (above 35 tera-electron-volts). The team shows that the number of tracks to showers is incompatible with exotic flavor ratios, such as 1:0:0 and 0:1:0. A similar analysis was performed by theorists at Italy’s Gran Sasso Science Institute in L’Aquila and the Gran Sasso Laboratories in Assergi. They focus on a higher energy range (above 60 tera-electron-volts) and find the ratio of tracks to showers is consistent with several astrophysical (nonexotic) models. Future data and analysis, which may include a method for tagging tau neutrinos, could eventually distinguish between these different source models.

I want to always try to impress upon people reading this, especially non-scientists, on how this is an example of "Physics doesn't just say what "What comes up, must come down". It must also say when and where it comes down!" In other words, there must be a strong QUANTITATIVE aspect of physics.

In this example, just detecting neutrinos is not sufficient (i.e. you found out that what goes up, must come down). The energy of the neutrinos, the interaction channels, etc...etc. are strict, mathematical descriptions that make numerical predictions (i.e. when and where it comes down). Only when the data are compared to these models can one distinguishes the type and nature of these neutrinos. Without the quantitative aspect of the physics, a neutrino will look like any other neutrinos.

Zz.

History of Physics Education in the US

I've only managed to read about 1/3 of the paper so far, but I thought I should highlight it on here for discussion for those so inclined.

There is a 12-page paper on the history of physics education in the US published in this month's issue of AJP[1]. Even though it is a "brief" overview of the history, it has to be one of the most comprehensive survey of physics education in the US that I've ever come across. It begins all the way back from 1860s to the present day, and looked at what has changed and what has remained the same.

I think that it is interesting to see some of the same efforts and arguments being made way back then, and to see how some things just are implemented or aren't effective. There's a lot of history to be learned from this paper because people tend to have short memory and do not remember what works and what doesn't.

Zz.

[1] D.E. Meltzer and V.K. Otero, Am. J. Phys. v.83, p.447 (2015).

How Big Is The Sun?

Hey, you get to use some of your high-school geometry and trig to make sense of this video!



Zz.

Accelerator Development For National Security

So let me point out this news article first before I go off on my rant. This article describes an important application of particle accelerators that has an important application in national security via the generation of high-energy photons. These photons can be used in a number of different ways for national security purposes.

The compact photon source, which is being developed by Berkeley Lab, Lawrence Livermore National Laboratory, and Idaho National Laboratory, is tunable, allowing users to produce MeV photons within very specific narrow ranges of energy, an improvement that will allow the fabrication of highly sensitive yet safe detection instruments to reach where ordinary passive handheld sensors cannot, and to identify nuclear material such as uranium-235 hidden behind thick shielding. "The ability to choose the photon energy is what would allow increased sensitivity and safety. Only the photons that produce the best signal and least noise would be delivered," explains project lead Cameron Geddes, a staff scientist at the Berkeley Lab Laser Accelerator (BELLA) Center.
.
.
.
To make a tunable photon source that is also compact, Geddes and his team will use one of BELLA's laser plasma accelerators (LPAs) instead of a conventional accelerator to produce a high-intensity electron beam. By operating in a plasma, or ionized gas, LPAs can accelerate electrons 10,000 times "harder" or faster than a conventional accelerator. "That means we can achieve the energy that would take tens of meters in a conventional accelerator within a centimeter using our LPA technology," Geddes says.

I've mentioned about this type of advanced accelerator scheme a few times on here, so you can do a search to find out more.

Now, to my rant. I hate the title, first of all. It perpetuates the popular misunderstanding that accelerators means "high energy physics". Notice that the production of light source in this case has no connection to high energy physics field of study, and it isn't for such a purpose. The article did mention that this scheme is also being developed as a possible means to generate future high-energy electrons for particle colliders. That's fine, but this scheme is independent of such a purpose, and as can be seen, can be used as a light source for many different uses outside of high energy physics.

Unfortunately, the confusion is also perpetuated by the way funding for accelerator science is done within the DOE. Even though more accelerators in the US is used as light sources (synchrotron and FEL facilities) than they are for particle colliders, all the funding for accelerator science is still being handled by DOE's Office of Science High Energy Physics Division. DOE's Basic Energy Sciences, which funds synchrotron light sources and SLAC's LCLS, somehow would not consider funding advancement in accelerator science, even though they greatly benefit from this field. NSF, on the other hand, has started to separate out Accelerator Science funding from High Energy Physics funding, even though the separation so far hasn't been clean.

What this means is that, with the funding in HEP in the US taking a dive the past several years, funding in Accelerator Science suffered the same collateral damage, even though Accelerator Science is actually independent of HEP and has vital needs in many areas of physics.

Articles such as this should make it clear that this is not a high energy physics application, and not fall into the trap of associating accelerator science with HEP.

Zz.

The compact photon source, which is being developed by Berkeley Lab, Lawrence Livermore National Laboratory, and Idaho National Laboratory, is tunable, allowing users to produce MeV photons within very specific narrow ranges of energy, an improvement that will allow the fabrication of highly sensitive yet safe detection instruments to reach where ordinary passive handheld sensors cannot, and to identify nuclear material such as uranium-235 hidden behind thick shielding. "The ability to choose the photon energy is what would allow increased sensitivity and safety. Only the photons that produce the best signal and least noise would be delivered," explains project lead Cameron Geddes, a staff scientist at the Berkeley Lab Laser Accelerator (BELLA) Center.

Read more at: http://phys.org/news/2015-04-national-high-energy-physics.html#jCp

The compact photon source, which is being developed by Berkeley Lab, Lawrence Livermore National Laboratory, and Idaho National Laboratory, is tunable, allowing users to produce MeV photons within very specific narrow ranges of energy, an improvement that will allow the fabrication of highly sensitive yet safe detection instruments to reach where ordinary passive handheld sensors cannot, and to identify nuclear material such as uranium-235 hidden behind thick shielding. "The ability to choose the photon energy is what would allow increased sensitivity and safety. Only the photons that produce the best signal and least noise would be delivered," explains project lead Cameron Geddes, a staff scientist at the Berkeley Lab Laser Accelerator (BELLA) Center.

Read more at: http://phys.org/news/2015-04-national-high-energy-physics.html#jCp

Quantum Entanglement For Dummies

Over the years, I've given many references and resources on quantum entanglement on this blog (check here for one of the more comprehensive references). Now, obviously, many of these sources are highly sophisticated and not really meant for the general public. It is also true that I continue to get and to see question on quantum entanglement from the public. Worse still, the Deepak Chopras of the world, who clearly do not understand the physics involved, are bastardizing this phenomenon in ridiculous fashion. But the final straw that compelled me to write up this thing is the episode of "Marvel Agent of Shield" from last night where the top brass of HYDRA was trying to explain to Bakshi what "quantum entanglement" is and how Gordon was using it to teleport from one location to another. ABSURD!

So while this is all brought about by a TV series, it is more of a reflection on how so many people are really missing the understanding of this phenomenon. So I intend to explain this is very simple language and using highly-simplified picture to explain what quantum entanglement is. Hopefully, it will diminish some of the false ideas and myth of what it is.

Before I dive into the quantum aspect of it, I want to start with something that is well-known, and something we teach even high school students in basic physics. It is the conservation of momentum. In Figure 1, I am showing a straight-foward example of conservation of linear momentum case, a common problem that we give to intro physics students.

In (a), you have an object with no initial linear momentum. In (b), it spontaneously splits into two different masses, m1 and m2, and go off in opposite directions. In (c), m1 reaches Bob and m2 reaches Alice. Bob measures the momentum of m1 to be p1.. Now, this is crucial. IMMEDIATELY, without even asking Alice, Bob knows unambiguously the momentum of m2 to be p2 simply via the conservation of linear momentum. He knows this instantaneously, meaning the momentum of m2 is unambiguously determined, no matter how far m2 is from Bob. When Alice finally measures the momentum of m2, she will find that it is, indeed, equal to p2.

Yet, in all the years that we learn classical physics, never once do we ever consider that m1 and m2 are "entangled". No mystical and metaphysical essays were ever written about how these two are somehow connected and can "talk" to each other at speeds faster than light.

Now, let's go to the quantum case. Similar scenario, outlined in Figure 2.

Here, we are starting to see something slightly different. We start with an object with no net spin in (a). Then it spontaneously splits into two particles. This is where it will be different than the classical case in Figure 1. Each of the daughter particles has a superposition of two possible spin states: up and down. This is what we call the SUPERPOSITION phenomenon. It was what prompted the infamous Schrodinger Cat thought experiment where the cat is both alive and dead. This is crucial to understand because it means that the state of each of the daughter particle is NOT DETERMINED. Standard QM interpretation says that the particle has no definite spin direction, and that until it is measured, both spin states are there!

Now, when one daughter particle reaches Bob, he then measures it spin. ONLY THEN will the particle be in a particular spin state (i.e. the commonly-described as wavefunction collapsing into a particular value). In my illustration, Bob see that it is in a spin-down state. Immediately, the spin state of other particle at Alice is in the spin-up state to preserve the conservation of spin angular momentum. When Bob measures the pin of his particle, he immediately knows the spin of the particle at Alice because he knows what it should be to conserve spin. This is similar to the classical case!

This superposition of state is what makes this different than the above classical example. In the classical case, even before Bob and Alice measure the momentum of their particles, there is no question that the particles have definite momenta all through its trajectory. Classical physics says that the momentum of each particle are already determined, we just need to measure them.

But in quantum physics, this isn't true. The superposition principle clearly has shown that in the creation of each of those two particles, the spin state are not determined, and that both possible states are present simultaneously. The spin state is only determined once a measurement is made on ONE of the particles. When that occurs, then the spin state of the other particle is also unambiguously determined.

This is why people have been asking how the other particle at Alice somehow knew the proper spin state to be in, because presumably, before any measurement is made, they both can randomly select either spin state to be in. Was there any signal sent from Bob's particle to Alice's to tell it what spin state to be in? We have found no such signal, and if there is, it has been shown that it will have to travel significantly faster than c. No matter how far apart the two daughter particles are, they somehow will know just what state to be in once one of them is measured.

This, boys and girls, is what we called quantum entanglement. The property of the quantum particles that we call "spin" is entangled between these two particles. Once the value of the spin of one particle is determined, it automatically forces the other particles to be in a corresponding state to preserve the conservation law.

But note that what is entangled is the property of the particle. It is the information about the property (spin) that is undergoing the so-called quantum teleportation. The particle itself did not get "teleported" the way they teleport things in Star Trek movies/TV series. It is the property, the information about the object, that is entangled, not the entire object itself. So in this example, the object doesn't jump around all over the place.

The physics and mathematics that describe quantum entanglement are more involved than this cartoon description, of course. There are mathematical rules resulting in physical constraints to the states and properties that are entangled. So you just can't pick up anything and say that you want to entangle it with something else. It just doesn't work that way, especially if you want to clearly observe the effects of the entanglement.

The important lesson to take away from this is that you can't learn physics in bits and pieces. If you simply focus on the "entanglement" aspect and are oblivious to understanding the existence of quantum superposition, then you will never understand why this is very different and mysterious than the classical case. In physics, it is not uncommon that you have to also understand a series of things leading up to it. This is why it is truly a knowledge and not just merely a series of disconnected information.

Zz.

Cyclotron Radiation From One Electron

It is a freakingly cool experiment!

We now can see the cyclotron radiation from a single electron, folks!

The researchers plotted the detected radiation power as a function of time and frequency (Fig. 2). The bright, upward-angled streaks of radiation indicate the radiation emitted by a single electron. It is well known theoretically that a circling electron continuously emits radiation. As a result, it gradually loses energy and orbits at a rate that increases linearly in time. The detected radiation streaks have the same predicted linear dependence, which is what allowed the researchers to associate them with a single electron. 

Of course, we have seen such effects for many electrons in synchrotron rings all over the world, but to not only see it for one electron, but to also see how it loses energy as it orbits around is rather neat. It reinforces the fact that we can't really imagine electrons "orbiting" around a nucleus in an atom in the classical way, because if they do, we would detect such cyclotron radiation and that they will eventually crash into the nucleus.

But I also find it interesting that this has more to do with the effort in trying to determine the mass of a neutrino independent of the neutrino mass oscillation via measuring the electrons mass to high accuracy in beta decay.

Zz.

Complex Dark Matter

Don Lincoln has another video on Dark Matter, for those of you who can't enough of these things.



Zz.

Tevatron Data Reveals No Exotic, Non-Standard Model Higgs

She may be long gone, but the old gal still has something to say.

A new paper that combined the data from CDF and D0, the two old Tevatron detectors at Fermilab, has revealed that the Higgs that has been found is indeed consistent with the Standard Model Higgs. It strengthens the much-heralded discovery made at CERN a while back.

...... the two Tevatron-based experiments, CDF and D0, uncovered evidence in 2012 of a Higgs boson decaying into fermions, specifically, a pair of bottom quarks. The two collaborations have again combined their data to check for exoticness in this fermion decay channel. The Tevatron data show no signal consistent with a Higgs boson having spin zero and odd parity (a so-called pseudoscalar) or spin 2 and even parity (gravitonlike). The results are important for building the case that the Higgs boson seen in particle colliders is indeed the standard model Higgs.

Zz.

More Quantum Physics In Your Daily Lives

I pointed to an article a while back about the stuff we use everyday that came into being because of our understanding of quantum mechanics (basically, all of our modern electronics). Now, Chad Orzel has done the same thing in his article on Forbes, telling you how you actually start your mornings by relying on the validity of QM.

The tiny scale of all the best demonstrations of quantum physics can lead people to think that this is all basically meaningless, arcane technical stuff that only nerds in white lab coats need to worry about. This is deeply wrong, partly because I don’t know any physicists who wear white lab coats, but more importantly because quantum phenomena are at the heart of many basic technologies that we use every day.

In fact, I can’t start my morning without quantum mechanics, in the form of my bedside alarm clock.

You may read the rest of his arguments in the article.

I will also add something that I've mentioned before. The presence of quantum effects may be more prominent than what most are aware of, if we go by the evidence for the existence of superconductivity. As stated by Carver Mead, it is the clearest demonstration of QM effects at the macro scale. Yet, a lot of people simply do not recognize it for what it is.

Zz.

Use "i,j,k" notation instead of "arrow" representation for vectors in Intro Physics?

That is what the authors of this study have found to be more effective in analyzing students understanding and ability to comprehend vector problems. (The paper is available for free.)

First, we replicated a number of previous findings of student difficulties in the arrow format and discovered several additional difficulties, including the finding that different relative arrow orientations can prompt different solution paths and different kinds of mistakes, which suggests that students need to practice with a variety of relative orientations. Most importantly, we found that average performance in the ijk format was typically excellent and often much better than performance in the arrow format in either the generic or physics contexts.

My question is, is this the result of an inherent conceptional problem in the arrow representation, or simply a matter of correcting some of the ways we teach vectors to students?

Zz.

How Do Airplanes Fly?

I get asked this often, strangely enough. So it is nice to have a quick illustration via a video on how it works.



Zz.

Where HEP Technology Becomes Commercial

This is a nice article to introduce you to all the benefits that the rest of world gets from the innovations that came about due to the experimental needs in high energy physics, nuclear physics, astrophysics, etc. The effort of HEPTech is clearly to make the technology transfer a conscious and systematic one, rather than just ad hoc or via accident.

Zz.

CERN Confirms The Existence of The Force

I can't let April 1st go without at least one goofy post, can I? So here it is!

Zz.

When Physics Demo Goes Wrong

Ouch!!!

Just found this news article on a physics demo for an AP physics class that didn't go as planned.

It apparently shows a physics teacher teaching a class a lesson by taking aim at a concrete block.

But he doesn’t quite hit the block correctly and ends up hitting a fellow teacher in a very sensitive area.

Now I'm all for doing demos in class, since not only can they be educational and fun, it also keeps the students from falling asleep. But I don't know if this is a bit on the more "daring" side. There's certainly plenty of chances for things to go wrong with demo such as this.

If anyone has any follow-up news on this, please let me know. The YouTube video implied that the teacher doing the demo lost his job, and there's confusion on the person holding up the blocks and got hit was another student or another teacher.

Zz.