Saturday, October 14, 2017

Lazy Reporting And Taking Way Too Much Credit

It is not surprising that whenever a major discovery is made or a major award is given, as many people and institutions want to ride the coattail and be a part of it. I understand that.

But sometime, it is stretching it a bit waaaay too much, especially when the report itself sounds very lazy and weak.

The recent announcement of the Nobel Prize in physics being awarded to 3 figures who are instrumental in the discovery of gravitational waves seem to be one such case. I stumble across this news article out of what I believe is a local newspaper called the "Gonzales Weekly Citizen". The headline said:

LSU scientists win Nobel Prize in Physics

Of course, that perked my interest since I didn't know any of the 3 men who were awarded the prize are known to be associated with LSU (Louisiana State University, for those who are not familiar with this).

Now, it seems that the reporter is playing fast and loose. Rainer Weiss is listed as an "adjunct professor" in the LSU physics dept. Now, we all know that an adjunct professor is nothing more than a "contractor". That person is not considered as a staff member, but rather hired on a per-term basis or based on a contract. In most cases, the person is probably associated by another institution rather than the one where he/she is an adjunct professor of.

In fact, in this case, Rainer Weiss is more well-known as being associated with MIT than anywhere else. It is what is listed in all the news report for this award. In fact, if you look at the Nobel Prize page that announced this award, the profile on Weiss says:

Affiliation at the time of the award: LIGO/VIRGO Collaboration, Massachusetts Institute of Technology (MIT), Cambridge, MA, USA

No mention of LSU. In fact, the LIGO project itself is a consortium of many universities and it is jointly administered by MIT and Caltech. One of the facilities may be in Louisiana, and LSU is involved in the project, but that's about it. They should be proud of their contribution to the project, but to over play it to this level is not quite right.

So this news report is misleading at best!

But that's not all! There's a certain level of laziness in the reporting.

LSU adjunct professor and MIT professor Emeritus Rainer Weiss and California professor Emeritus Kip Thorne are co-founders of the collaboration. Weiss won half of the prize, and the other half went to the California Institute of Technology professors involved.

I'm sorry, but they could not even bother to mention Barry Barish name? He's being relegated to being part of the "... California Institute of Technology professors involved." REALLY!

As I said, rather lazy reporting.


Wednesday, October 11, 2017

Electron Is Still A Point Particle

There have been experiments to measure the electric dipole moment of an electron, if any, which would indicate that (i) an electron has an internal structure and (ii) consequently it isn't a point particle that we have been assuming within QED. So far, all the experiments have not found any, and each measurement continues to increase the precision of the previous measurement.

Chalk this one up to follow the same trend[1]. This time, they are using a different technique to measure the electron dipole moment by using trapped molecular ions. The result of the experiment is an even more precise measurement, and lowered the upper bound of the dipole moment by several orders of magnitude when compared to the previous result.

Electron is still a spherical cow!


[1] W.B. Cairncross et al., Phys. Rev. Lett. v.119, p.153001 (2017).

Tuesday, October 03, 2017

Why You Can't Go Faster Than Light

Don Lincoln tackles our speed limit.


2017 Physics Nobel Prize Goes To Gravitational Wave Discovery

To say that this is a no-brainer and no surprise are an understatement.

The 2017 Nobel Prize in Physics goes to 3 central figures that made LIGO possible and the eventual discovery of gravitational wave in 2015.

The Nobel Prize in Physics 2017 was divided, one half awarded to Rainer Weiss, the other half jointly to Barry C. Barish and Kip S. Thorne "for decisive contributions to the LIGO detector and the observation of gravitational waves".

Congratulations to all of them!


Friday, September 22, 2017

Common Mistakes By Students In Intro Physics

Rhett Allain has listed 3 common mistakes and misunderstanding done by student in intro kinematics physics courses.

I kinda agree with all of them, and I've seen them myself. In fact, when I teach "F=ma" and try to impress upon them its validity, I will ask them that if it is true, why do you need to keep your foot on the gas pedal to keep the vehicle moving at constant speed while driving? This appears to indicate that "F" produces a constant "speed", and thus, "a=0".

Tackling this is important, because the students already have a set of understanding of how the world around the works, whether correctly or not. It needs to be tackled head-on. I tackled this also in dealing with current where we calculate the drift velocity of conduction electrons. The students discover that the drift velocity is excruciatingly slow. So then I ask them that if the conduction electrons move like molasses, why does it appear that when I turn the switch on, the light comes on almost instantaneously?

Still, if we are nitpicking here, I have a small issue with the first item on Allain's list:

What happens when you have a constant force on an object? A very common student answer is that a constant force on an object will make it move at a constant speed—which is wrong, but it sort of makes sense.

Because he's using "speed" and not "velocity", it opens up a possibility of a special case of a central force, or even a centripetal force, in a circular motion where the object has a net force acting on it, but its speed remains the same. Because the central force is always perpendicular to the motion of the particle, it imparts no increase in speed, just a change in direction. So yes, the velocity changes, but the magnitude of the velocity (the speed) does not. So the misconception here isn't always wrong.


Thursday, September 21, 2017

Gravity As A Result Of Random Quantum Fluctuation?

There are too many "buzzwords" in this entire thing, but it might still be an interesting reading for some people.

There is a new report on the possibility that gravity might not be an interaction within QFT framework, but rather as a result of quantum fluctuation.

The average of these fluctuations is a gravitational field that is consistent with Newton’s theory of gravity. In this model, gravity is born out of quantum mechanics, but is not in itself a quantum-mechanical force. It is what scientists call “semiclassical.” Until this theory is tested further, it will remain a semi-solution; while the idea does predict certain known phenomena, it doesn’t yet account for Einstein’s theory of general relativity.

This latest report is due to a preprint uploaded to ArXiv.

Now, I can understand New Scientist reporting on something like this, because they have the tendency to report on sensational and unverified science news, but for PBS/NOVA webpage to jump onto this still-unpublished work? That's surprising.

Of course, I'm complicit on this as well since I'm reporting it here. I'm going to make sure I won't highlight something like this again in the future until it has at least appear in a peer-reviewed publication, not just in New Scientist and the likes.


Tuesday, September 19, 2017

Amazon's CAPTCHA Patent Proposal Tests Your Physics Understanding

... well, more like your physics INTUITION on what should happen next.

It seems that Amazon has file a patent application that uses a physics engine to generate scenarios to see if you are a real person or a bot.

The company has filed a patent application for a new CAPTCHA method which would show you a 3D simulation of something about to happen to a person or object. That something would involve Newtonian physics — perhaps an item is about to fall on someone, or a ball is about to roll down a slope. The test would then show you several "after" scenarios and, if you pick the correct option, you've passed the test.
The idea is that, because you are a human, you have an "intuitive" understanding of what would happen next in these scenarios. But computers need much more information about the scene and "might be unable to solve the test", according to the application.

Definitely interesting, although in Fig. 3B shown in the article, both Fig (A) and Fig (B) might be possible depending on the ambiguity of the drawing.

But this brings me an important point that I've been telling my students in intro physics classes when they dealt with mechanics. We all ALREADY KNOW many of the things that will happen in cases like this. We do not need to learn physics or to be enrolled in a physics class to know the qualitative description of the dynamics of these systems. So we are not teaching you about something you are not familiar with.

What a formal physics lesson will do is to describe these things more accurately, i.e. in a QUANTITATIVE manner. We won't simply say "Oh, the ball will roll down that inclined plane." Rather, we will describe the motion of the ball mathematically, and we will be able to say how long the ball will take to each the bottom, at what speed, etc...etc. In other words, we don't just say "What goes up must come down", but we will also say "When and where it will come down". This is what separates physics (and science) from hand-waving, everyday conversation.

All of us already have an intuitive understanding of the physical systems around us. That's why Amazon can make such a CAPTCHA test for everyone. A physics lessons simply formalize that understanding in a more accurate and non-ambiguous fashion.


Friday, September 15, 2017

Bell's Theorem - The Venn Diagram Paradox

Minute Physics is tackling Bell's theorem, with limited success.

It would have been nice if they included Malus' Law description in here, because that is what we knew before QM came around, and that is what we teach students in intro physics.

In any case, I still find it difficult to follow, especially if you didn't pay that much attention to the part when they are doing the counting. They went over this a bit too quickly to let it sink in.

Maybe your brain works faster than mine and can keep up.


Sunday, September 10, 2017

Is Relativistic Mass Real?

I've mentioned about this issue several times on here. In this post, I've linked to a reference, and also a link to Lev Okun's paper in another post, that both debunked the concept of relativistic mass, and why it should not be used.

Unfortunately, as a physics instructor, I still see texts teaching this concept, and I have to work around it, telling the students the caveat on why what they should be cautious in what they are reading. It isn't easy, but I'd rather say something about it than let the students walk out of my class not knowing that this idea of "relativistic mass" is not what it has been popularly made out.

So I'm delighted that Don Lincoln has a video addressing this issue as well.

He explains it quite clearly, and also why we still sometime teach this concept to students in intro classes (unfortunately). Yes, I can understand why, but I still don't like it if it can be avoided without sacrificing the pedagogical reason for it.

It's a good video if you are still wondering what the fuss is all about.


Sunday, September 03, 2017

Rebuilding Quantum Theory

Theorists and philosophers are trying to "rebuild" quantum theory's foundation and axioms. Good luck to them!

Still, this is a rather good article on some of the issues surrounding concepts that still do not sit well with many physicists. Those of us who are in the "Shut up and calculate" camp will leave it up to them to sort things out. We are busy with doing other things.



Sunday, August 20, 2017

RIP Vern Ehlers

The first physicist ever elected to the US Congress has passed away. Vern Ehlers, a moderate Republican from Michigan, passed away at the age of 83.

Vern Ehlers, 83, a research physicist and moderate Republican who represented a western Michigan congressional district for 17 years, died late Tuesday at a Grand Rapids nursing facility, Melissa Morrison, funeral director at Zaagman Memorial Chapel, said Wednesday.

I reported on here when he decided to retire back in 2010. And of course, when he was serving Congress along with 2 other elected officials who were physicist, I cited a NY Times article that clearly demonstrated how desperate we are to have someone with science background serving as politicians.

Unfortunately, right now, the US Congress has only ONE representative who is a trained physicist (Bill Foster). It somehow reflects on the lack of rationality that is going on in Washington DC right now.


Solar Eclipse, Anyone?

It's a day before we here in Chicago will get to see a partial solar eclipse. I know of people who are already in downstate Illinois at Carbondale to view the total eclipse (they will get another total eclipse in 2024, I think).

So, any of you will be look up, hopefully with proper eye wear, to view the eclipse tomorrow? I actually will be teaching a class during the main part of the eclipse, but I may just let the students out for a few minutes just to join the crowd on campus who will be doing stuff for the eclipse. Too bad I won't be teaching optics, or this will be an excellent tie-in with the subject matter.


Tuesday, August 08, 2017

Hyperfine Splitting of Anti-Hydrogen Is Just Like Ordinary Hydrogen

More evidence that the antimatter world is practically identical to our regular matter world. The ALPHA collaboration at CERN has reported the first ever measurement of the anti-hydrogen hyperfine spectrum, and it is consistent to that measured for hydrogen.

Now, they have used microwaves to flip the spin of the positron. This resulted not only in the first precise determination of the antihydrogen hyperfine splitting, but also the first antimatter transition line shape, a plot of the spin flip probability versus the microwave frequency.

“The data reveal clear and distinct signatures of two allowed transitions, from which we obtain a direct, magnetic-field-independent measurement of the hyperfine splitting,” the researchers said.

“From a set of trials involving 194 detected atoms, we determine a splitting of 1,420.4 ± 0.5 MHz, consistent with expectations for atomic hydrogen at the level of four parts in 10,000.”

I am expecting a lot more studies on these anti-hydrogen, especially now that they have a very reliable way of sustaining these things.

The paper is an open access on Nature, so you should be able to read the entire thing for free.