Tuesday, September 29, 2015

Football Physics and Deflategate

This issue doesn't seem to want to go away.

Still, anyone who has been following this (at least here in the US) have heard of the "Deflategate" controversy from last year's NFL Football playoffs.

Chad Orzel has another look at this based on a recent paper out of The Physics Teacher, this time, from the physics involved with the football receivers.

Most of the coverage of “Deflategate” has focused on Patriots quarterback Tom Brady, and speculation that he arranged for the balls to be deflated so as to provide a better grip. The authors of the Physics Teacher paper, Gregory DiLisi and Richard Rarick look at the other end of the problem, where the ball is caught by the receiver, thinking about it in terms of energy, an issue with major implications for the existence of atomic matter.

It certainly is another angle to the issue. I hope to get a copy of the paper soon and see what it says.


Friday, September 25, 2015

Why Do We Put Telescope In Space?

Here's the Minute Physics explanation:


Friday, September 18, 2015

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!


Monday, September 14, 2015

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.


Wednesday, September 09, 2015

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.


Tuesday, September 08, 2015

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.


Monday, September 07, 2015

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.


Thursday, September 03, 2015

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.