Saturday, August 20, 2016

Brain Region Responsible For Understanding Physics?

A group of researchers seem to think that they have found the region of the brain responsible for "understanding physics".

With both sets of experiments, the researchers found that when the subjects tried predicting physical outcomes, activity was most responsive in the premotor cortex and supplementary motor region of the brain: an area described as the brain’s action-planning region.

“Our findings suggest that physical intuition and action planning are intimately linked in the brain,” said Fischer. “We believe this might be because infants learn physics models of the world as they hone their motor skills, handling objects to learn how they behave. Also, to reach out and grab something in the right place with the right amount of force, we need real-time physical understanding.”

But is this really "understanding physics", though?


Who Will Host The Next LHC?

Nature has an interesting article on the issues surrounding the politics, funding, and physics in building the next giant particle collider beyond the LHC.

The Japanese are the front-runner to host the ILC, but the Chinese have their own plans on a circular electron-positron collider that can be upgraded to a future proton-proton collider.

And of course, all of these will require quite a bit of chump change to fund, and will be an international collaboration.

The climate in the US continues to be very sour in building anything like this.


Thursday, August 18, 2016

Could You Pass A-Level Physics Now?

This won't tell if you will pass it, since A-Level Physics consists of several papers, including essay questions. But it is still an interesting test, and you might make a careless mistake if you don't read the question carefully.

And yes, I did go through the test, and I got 13 out of 13 correct even though I guessed at one of them (I wasn't sure what "specific charge" meant and was too lazy to look it up). The quiz at the end asked if I was an actual physicist! :)

You're probably an actual physicist, aren't you?

Check it out. This is what those A-level kids had to content with.


Friday, August 12, 2016

Proton Radius Problem

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

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


The Science of Sports

With the Olympics in full swing right now, the Perimeter Institute has released a series that discusses the physics behind various sports at the Games. Called The Physics of the Olympics, it covers a wide range of events.


Monday, August 08, 2016

CP Violation in Neutrino Oscillation

It is always nice when non-science media carries physics news. Unfortunately, often times, the accuracy is lacking and, in many cases, gives misleading ideas. This is one such case.

It is reporting on the news about CP violation in neutrino oscillation from muon neutrinos and muon antineutrinos that was reported in last week's 2016 ICHEP.

At the T2K experiment, researchers looked for a difference between neutrinos and antineutrinos oscillations. Their findings, announced at the International Conference on High Energy Physics in Chicago, suggest that there are — more muon neutrinos were found changing into electron neutrinos than muon antineutrinos changing into electron antineutrinos.

The researchers, who had expected to detect 23 electron neutrinos and seven electron antineutrinos, observed 32 electron neutrinos and 4 electron antineutrinos.

If confirmed with a greater level of certainty, this would point to a violation of charge-parity (CP) symmetry in neutrinos. CP symmetry tells us that a system remains unchanged even if two fundamental properties — charge and parity, which refers to a 180-degree flip in spatial configuration — are reversed. If a violation of CP symmetry is confirmed, it would not only hint at the existence of physics beyond the Standard Model — a theory of almost everything — it would also help us understand why the universe is completely devoid of antimatter.

There's nothing wrong with the report. However, it is inaccurate with regards to what it left out. If you don't know any better, you'd think that this is something new, and that this is the first instance of CP violation. This is not true. CP violation has been seen in other particle systems. So there is no longer a question on whether such violation exists. What is new here is that it is the first time it is observed in neutrino oscillation.

This is why science reporting is difficult. You need someone who has a wide breadth of knowledge in many fields to be able to not only report things accurately, but also give a full view of it. There's nothing inaccurate here in what was included. But the inaccuracy occurs on what was omitted, and therefore, not giving a general reader a more complete state of knowledge of the field.


Friday, August 05, 2016

The 750-GeV Blip At LHC - It Came And Went

A lot of HEP were in a tizzy since last year over the unexpected peak in the data at 750 GeV. And now, early reports from the current meeting going on in Chicago are indicating that this might be just a statistical anomaly.

Sadly, it seems that the 750 GeV particle wasn’t meant to be. Physicists at the International Conference on High Energy Physics (ICHEP) in Chicago were due to reveal the latest data on the excess of photon pairs at 750 GeV later today, but a paper accidentally posted online last night by the CMS collaboration states that their new round of data found no extra photons. This suggests the earlier hints were just a statistical fluke.

“As data comes in, excesses tend to come and go,” says CMS researcher Nadja Strobbe at Fermilab, near Batavia, Illinois. Researchers from ATLAS are due to present their results later today, but rumours suggest they will announce that the 750 GeV bump is gone.

But the fun part is all the theory papers that came gushing out as soon as the possibility of this being real.

A week after the announcement, theorists had written over 100 possible explanations; today, there are over 500. Nearly all of these papers posit the existence of a particle with a mass of 750 GeV or higher whose decay created the extra photons. Because this particle would have been outside the standard model of particle physics, it could have forced a reconsideration of how particles and forces interact.

I've always been curious to ask many of the people who did similar things on what they have to say for themselves. They had just created an explanation for the existence of the unicorn.

This is not new. When the OPERA collaboration indicated a faster-than-light neutrino detection a few years ago, numerous theory papers came out for that as well, proposing a myriad of particles and new physics. This is all before this result was confirmed. And of course, we all know what happened with that one as well.

I guess that people would rather be FIRST to be correct rather than be cautious and not appear foolish. After all, how many of us would remember that such-and-such wrote a paper to explain something that never existed in the first place?


Thursday, August 04, 2016

Combining QM, SR, and HEP is "New"?

Often times, when science news is reported in the mass media, while the reporting might be somewhat accurate, the implications that it leaves behind, especially when read by someone not trained in that area, may lead to a horribly wrong idea. This might be the case here.

This news report is covering a paper out of the Princeton's Plasma Physics Lab (PPPL) on a new theoretical model to explain a plasma physics phenomenon. Nothing wrong there. However, I have a lot of issues with this part of the report very early on:

Researchers at the Princeton Plasma Physics Laboratory (PPPL) have developed a new way to explore some of the most extreme environments in the universe by combining three separate branches of physics: High energy physics (which describes charged particles traveling at or close to the speed of light), quantum mechanics (which describes the motion of subatomic particles), and Einstein’s theory of special relativity (which describes the propagation of matter and light at high speeds).

“People haven’t done this before,” Yuan Shi, a graduate student in the PPPL and lead author of a paper published July 29 in the journal Physical Review A, told Business Insider. “Nobody really wanted to cross the boundaries between the disciplines to see what other scientists are doing. The difficulty was mostly that there’s no communication between these fields.” 

Now, I'm sure that if you are a physics, or even a graduate student in physics, you can already spot something odd here. The existence of quantum field theory (QFT) is already evidence that Special Relativity (SR) has already been incorporated inside quantum mechanics (QM). And high energy physics (HEP) is a field that makes use of QFT!

But if you don't know that, then reading this news report will give you the impression that this isn't known till now, and that this is all new!

And the statement made that "People haven't done this before" with regards to crossing boundaries between disciplines in physics is blatantly false, especially with all the brouhaha surrounding the discovery of the Higgs within the the past couple of years. Anyone following the history of the Higgs field will have seen how the idea originated out of a condensed matter system, and how Phil Anderson, a condensed matter physicist and a Nobel laureate, was himself a strong candidate to be considered for the Nobel prize when the Higgs was finally discovered.

I know that press releases can sometime over-glorified the importance and significance of something. But there really is an important mission here to make sure that one is conveying a message that is clear and unambiguous to the audience that can easily be misled. What you mean may not be exactly what they understand!


Wednesday, July 06, 2016

Photoemission Spectroscopy - Fundamental Aspects

I don't know if this is a chapter out of a book, or if this is a lecture material, or what, but it has a rather comprehensive coverage of photoionization, Auger, and photoemission in solids. I also don't know how long the document will be available (web links come and go, it seems). So if this is something you're interested in, it might be something you want to download.

At the very least, it has an extensive collection of references, ranging from Hertz's discovery of the photoelectric effect, to Einstein's photoelectric effect paper of 1905, all the way to Spicer's 3-step model and recent progress in ARPES.


Monday, June 27, 2016

Landau's Nobel Prize in Physics

This is a fascinating article. It describes, using the Nobel prize archives, the process that led to Lev Landau's nomination and winning the Nobel Prize in physics. But more than that, it also describes the behind-the-scenes nominating process for the Nobel Prize.

I'm not sure if the process has change significantly since then, but I would imaging that many of the mechanism leading up to a nomination and winning the prize are similar.


Wednesday, June 08, 2016

New Physics Beyond The Higgs?

Marcelo Gleiser has written a nice article on the curious 750 GeV bump coming from the LHC as announced last year. It is a very good article for the general public, especially on his condensed version of the analysis provided by PRL on the possible origin of this bump.

Still, there is an important point that I want to highlight that is not necessarily about this particular experiment, but rather about physicists and how physics is done. It is in this paragraph:

The exciting part of this is that the bump would be new, surprising physics, beyond expectations. There's nothing more interesting for a scientist than to have the unexpected show up, as if nature is trying to nudge us to look in a different direction.

If you have followed this blog for a considerable period of time, you would have read something similar in my many postings. This is especially true when I tried to debunk the erroneous claim of many crackpots who keep stressing that scientists are merely people who simply work within the box, and can't think outside of the box, or refuse to look for something new. This is of course, utterly dumb and false, because scientists, by definition, study things that are not known, not fully understood, etc. Otherwise, there will be no progression of knowledge the way we have seen it.

I'm going to keep harping this, because I continue to see nonsense like this being perpetuated in many different places.


Tuesday, May 31, 2016

Stephen Hawking Doesn't Understand Donald Trump

When interviewed by Good Morning Britain, Stephen Hawking professed his lack of understanding of the popularity of Donald Trump in the US.

World-renowned British physicist Stephen Hawking may understand the many mysteries of the universe, but even he's having a hard time grasping Donald Trump's meteoric rise in popularity.

In an interview with ITV's “Good Morning Britain” today, Hawking called Trump a "demagogue" who seemed to attract the "lowest common denominator."

I would go even lower than that, all the way back to single-cell amoeba! :)


Thursday, May 19, 2016

The Curse Of Being A Physicist

When do you speak up in a social setting and set someone straight?

I think I've mentioned a few times on here of being in a social setting, and then being found out that I'm a physicist. Most of the time, this was a good thing, because I get curious questions about what was on the news related to physics (the LHC was a major story for months).

But what if you hear something, and clearly it wasn't quite right. Do you speak up and possibly might cause an embarrassment to the other person?

I attended the annual Members Night at the Adler Planetarium last night here in Chicago. It was a very enjoyable evening. Their new show that is about to open on "Planet Nine" was very, VERY informative and entertaining. I highly recommend it. We got to be among the first to see it before it is opened to the public.

Well, anyway, towards the end of the evening, before we left, we decided to walk around the back of the facility and visit the Doane Observatory. The telescope was looking at Jupiter which was prominent in the night sky last night. There was a line, so we waited in the line for our turn.

As we progressed up, I and my companions heard these two gentlemen chatting away with the visitors, and then to each other about their enthusiasm about astronomy and science, etc. This is always good to know, especially at an event like this. As I got closer to them, it turned out that they were either volunteers, or were working for Adler Planetarium, because they were wearing either name tags or something. One of them identified himself as an astronomer, which wasn't surprising considering the event and the location.

But then, things got a bit sour, at least for me. In trying to pump up their enthusiasm about astronomy and science, they started quoting Carl Sagan's famous phrase that we are all made up of star stuff. This wasn't the bad part, but then they took it further by claiming that hydrogen is the "lego blocks" of the universe, and that everything can be thought of as being built out of hydrogen. One of them started giving an example by saying that you take two hydrogen and put them together, and you get helium!

OK, by then, I was no longer amused by these two guys, and was tempted to say something. I wanted to say that hydrogen is not the "lego blocks" of our universe, not if the Standard Model of Particle Physics has anything to say about that. And secondly, you don't get helium when you put two hydrogen atoms together. After all, where will the extra 2 neutrons in helium come from?

But I stopped myself from saying anything. These people were working pretty hard for  this event, they were trying to show their enthusiasm about the subject matter, and we were surrounded by other people, the general public, who obviously were also interested in this topic. Anything that I would have said to correct these two men would not have looked good, at least that was my assessment at that moment. It might easily led to an awkward, embarrassing moment.

I get that when we try to talk to the public about science, we might overextend ourselves. I used to give tours and participated in outreach programs, so I've been in this type of situation before. While I tried to make sure everything I say was accurate, there were always possibilities that someone in the audience may know more about something I said and may find certain aspects of it not entirely accurate. I get that.

So that was why I didn't say anything to these two gentlemen. I think that what they just told to the people who were within ear shot of them were wrong. Maybe their enthusiasms made them forget some basic facts. That might be forgivable. Still, it is obvious that I'm still thinking about this the next morning, and second guessing if maybe I should have told them quietly that what they said wasn't quite right. Maybe it might stop them from saying it out loud next time?

On the other hand, how many of these people who heard what was said actually (i) understood it and (ii) remembered it?


Still No Sterile Neutrinos

IceCube has not found any indication of the presence of sterile neutrinos after looking for it for 2 years, at least not in the energy range that it was expected.

In the latest research, the IceCube collaboration performed independent analysis on two sets of data from the observatory, looking for sterile neutrinos in the energy range between approximately 320 GeV and 20 TeV. If present, light sterile neutrinos with a mass of around 1 eV/C2 would cause a significant disappearance in the total number of muon neutrinos that are produced by cosmic-ray showers in the atmosphere above the northern hemisphere and then travel through the Earth to reach IceCube. The first set of data included more than 20,000 muon-neutrino events detected between 2011 and 2012, while the second covered almost 22,000 events observed between 2009 and 2010. 

I think there are other facilities that are looking for them as well. But this result certainly excludes a large portion of the "search area".