What's The Difference?

OK, I have two figures here for you:

A.

B.

Other than the orientation and the pixel density, can you tell what is what in these two, and what are the differences?

No?

What if I tell you that one is a 2-slit interference experiment using single electrons, while the other is a 2-slit interference experiment using single photons. Can you tell which is which?

You are not at fault if you can't, because I won't be able to either, just from looking at the figures. Figure A is the single-photon interference experiment, while Figure B is the single-electron interference experiment (G. Matteucci et al., Eur. J. Phys. v.34, p.511 (2013)). The effects look the same for both.

Zz.

Observing Matter-Antimatter Oscillations

This result out of LHCb on the B-meson matter-antimatter oscillation has been getting a little bit of publicity lately (see the PhysicsWorld coverage). The paper has now appeared on PRL, and you can get a free copy of the paper at the APS Physics link.

Zz.

"Admissions Criteria and Diversity in Graduate School"

I only managed to read through this article yesterday, so this is a bit late for something that has appeared for a while.

This is a rather interesting article that first appeared in the APS News. It examines that effect of using a GRE cutoff score as a basis for graduate admission in physics, and how this may contribute to a reduced diversity for American students.

Justifying using the GRE becomes significantly more complicated, however, when the test results are dissected by race and gender. The figure plots QGRE scores by race/ethnicity and gender for US citizens whose intended graduate major was "physical sciences". The top and bottom of the lines are the 75th and 25th percentiles of the score distributions, respectively; the tick is the mean. This pattern is qualitatively unchanged when controlling for undergraduate GPA. Note the implications for diversity of using 700 as a minimum acceptable score: nearly three quarters of Hispanics would be rejected, and significantly more than this for American Indians, African Americans, and Puerto Ricans; similarly, women are filtered out at a higher rate than men. Mixing cut-off scores with these racial and gender disparities sets the foundation of a glass ceiling erected by the lopsided treatment of minorities and women before they even set foot in grad school. 

The author certainly presented some compelling statistics on why the GRE cutoff rule not only does not provide a good prediction on a student's performance in a graduate program, but also contributes to racial and gender disparities in admission.

And this brings me to another, slightly different item of discussion. The article looks at the diversity among the US students in physics. Many of us who went through the STEM educational program often see not only US students, but a large population of international students in these programs. In fact, in many schools, especially smaller ones, the number of international students can outnumber US students. This is definitely true in physics and engineering. There is a large population of international students from China, India, Korea, South America, etc.. So while there may not be as much "diversity" in the US student population in STEM fields, I find that there is a huge degree of diversity for the overall student population in these fields of study, more so then students in the liberal arts, economics, law, etc. Did you take an elective course in literature, art history, philosophy, etc.? How diverse in terms of racial/national origin were the students? How about those majoring in those fields?

Students in STEM areas have a larger opportunity to interact and experience students from other cultures and nationalities over a longer period of time. Often, they go through the degree program together. They tend to be more familiar in dealing with people from a wide variety of background. And you know what? If they continue work in such fields, the diversity carries over. Attend any physics or engineering conference, and you'll find a huge and significant international participation.

This diversity in STEM areas is often overlooked and is seldom considered as a strength in the development of students going through the program.

Zz.

Physics And Your Food Blender

I've mentioned several times on here on the effort to clearly demonstrate how physics is at work in the world of gastronomy. This is not entirely there, but certainly related to it. It is a Wired article on how the blender works, including a video that demonstrate what happens during its operation.

Question is, will it help me to make a better margarita? :)

Zz.

Measurement Of The Neutrino Oscillation Angle Theta13

This is a very good review article on neutrino oscillation and also the measurement of Theta13, which has been a very active investigation area lately. The article is aimed at "non-HEP Physicists", meaning you have to remember quite a bit of your quantum mechanics to decipher all those matrices. You get to see, quite early on, why the detection of the change in flavor of neutrinos allows not only the measurement of the mixing angle, but also implies that neutrinos must have mass.

Zz.

High-Energy Physics Is Still a Worthwhile Investment

Not sure if there's a contagious disease going on, or if something is up somewhere, but we now have two different articles written about the worthwhile investment in High Energy Physics, within the span of a couple of days.

Granted, the earlier one was done by an "amateur" for a school newspaper. This latest version appeared in The Atlantic and written by a physicist.

Wilson could have made a case for investments in high-energy physics transferring directly to national security. And in the decades since 1969, they have. Detectors developed in searches for dark matter, believed to make up 23 percent of the content of the universe, could notice a dirty bomb crossing our borders. Beams of particles can scan cargo containers without opening them, or even scan people and their luggage at airports, as is now commonplace all over the world. Beyond security and shrink wrap, we have also seen advances in medicine, computing, and data mining. According to the U.S. Department of Energy, tens of millions of patients receive accelerator-based diagnosis or therapy each year.

In the decades since 1970, high-energy physics has made stunning progress in the archeology of the early moments of the Big Bang. In the same timeframe the fraction of the U.S. gross domestic product dedicated to research in the physical sciences has been cut in half. We are currently in a situation where the next machine, either taking us to higher energy or allowing us to probe this potential Higgs boson in greater detail, might be out of reach of our finances and political will.

It certainly is true that high energy physics gave birth to the field of accelerators. However, as it is now, the field of accelerator physics certainly has been clearly separated from high energy physics. In fact, the overwhelming number of accelerators in this world have nothing to do with high energy physics. Still, the need for cheaper, more efficient future particle colliders at higher energies will continue to drive innovations in accelerator physics that will translate into better accelerators for other applications.

Zz.

The Devastating Mathematics Of Budget Cuts In The US

The failure of the US politicians to come up with a budget to prevent the current sequestration is devastating to science research and funding. There is an almost universal agreement on this. However, the way it is done is even more devastating that many people realize, and I often wonder if the politicians that are doing this realize this as well. I'm tempted to think that some of them do not realize this, because this is done often enough, year-after-year, that they don't seem to understand the severity of what they are doing.

Here are some simple mathematics that anyone can understand, and it illustrates the utter stupidity of what they are doing.

Let's say that Govt. Agency X has a budget of x. This is the amount of money that they are given for the fiscal year (12 months). So on average, this agency has x/12 amount of money to spend per month, which is 0.083x per month.

Budget = x
Spending per month = x/12 = 0.083x

OK so far?

Now, since Congress can't get their act together and come up with a budget when they are supposed to by the end of September, they pass this thing called "Continuing Resolution". This is where, devoid of a budget for the new fiscal year, they continue working using the budget of the previous year until a new budget is agreed upon. So this agency will continue to work under the assumption that it has x amount of money in a fiscal year! In other words, the agency will continue to spend, on average, 0.083x per month.

Average spending per month for new fiscal year = 0.083x

Now, let's say, at the end of February of the following year (i.e. 5 months into the new fiscal year), a new budget is agreed upon and takes effect. This means that Agency X has spent:

Amount of money spent = 0.083x * 5 months =  0.417x. ----- (1)

So this agency has spend 0.417x amount of money already by the end of February.

Unfortunately for Agency X, its budget was cut by 12% (the same devastating amount being cut during this sequestration). What this means is that instead of getting x for the new fiscal year, the agency is supposed to get 0.88x.

Budget for new fiscal year = 0.88x
Average spending per month = 0.88x/12 = 0.073x

By the beginning of March (after 5 months into the new fiscal year), this agency should have 0.513x amount of money left, i.e.

0.88x - (5 * 0.073x) = 0.515x

But that is not what is going on. Because of the continuing resolution, the agency was spending, on average, 0.083x per month, for 5 months, for a total of 0.417x (see (1)). The amount of money left for this agency is:

Amount of money left = 0.88x - 0.417x = 0.463x. !!!!!!!!!!!!!!!!!

This is significantly different and LOWER than 0.515x amount of money had the budget cut been applied AT THE START OF THE FISCAL YEAR. This agency is in a deeper financial trouble by this time because it has even less money than expected.

There are two devastating impact here:

1. The budget for this agency was cut from x to 0.88x. That in itself creates major problem

2. However, it was made WORST when congress could not come up with a budget when it should and instead, applied a continuing resolution for several month before indicating that this agency will get a budget cut.

The agency would have been better off to receive a budget of 0.88x at the start of the fiscal year. It knows what it has to spend. Instead, not knowing and having to spend using the old budget only causes it to spend on money that it won't have. The longer the continuing resolution goes on, the more devastating the cut will be.

This is what is going on right now in the US budget. We were under a continuing resolution since the start of Oct. of 2012. The 12% budget cut due to the sequestration is devastating because the money that's left is significantly smaller than had the 12% cut been applied at the beginning of the fiscal year. The budget cut is bad enough. The inability of Congress to come up with a budget ON TIME, WHEN IT SHOULD, creates a double-whammy.

In case you think what is happening this year is unique, think again. I do not remember the last time the US Congress managed to come up with a budget on time, when it should. The continuing resolution legislation has been invoked almost every single year lately, it seems. When this happens, any branch of the Govt. that ends up receiving a budget cut often has to deal with massive problems in trying to balance out what needs to be done and what has to go.

We ask our elected officials in Washington to do two major tasks: (i) come up with sensible legislation and (ii) come up with a federal budget. One can argue about how successful they are with (i), but for (ii) they have done an extremely poor job as far as the timeliness of what they should accomplish. For most of us, we get penalized for not completing something on time, when we're supposed to. Obviously, this doesn't apply to those who come up with our Federal budget.

Zz.

Catch And Release Of Photons

I'm always amazed by the nature of these experiments, and continue to be awed by what have been accomplished.

Two different groups published two different papers in this week's PRL, all reporting on the ability to store photons and then releasing them. What is even fascinating is that each group used different schemes to accomplish the same thing. I already reported on one of these results earlier. So check out the first link for a review of these two experiments, and you also get a link to free access to both papers.

Zz.

Chasing The Higgs

Quick, read it before the free, open access goes away!

The NY Times has a lengthy article on the hunt for the Higgs (yeah, yeah, I know. Another one!). Still, it is nice that a prominent newspaper is still covering something like this.

As you read it, take note of the cast of characters in the story. If you are not familiar with the type of collaboration in one of these large science projects, note that many of the people who are associated with CERN or the LHC or the hunt for the Higgs are NOT CERN employees! Many, if not most, of them are employed by other institutions. They just happen to do their job AT CERN or AT the LHC.

I mention this because I've been asked by so many kids who want to work for LHC, or who wants to work for NASA etc. They think that the only way to be involved in these things is to be employed by those organizations, when nothing can be further from the truth. Many of these projects are run, administered, etc., by people from other organizations. Here in the US, people who work at many of the large facilities at various US National Labs are NOT necessarily employees of those laboratories. Large user facilities such as the NSLS, APS, SNS, LCLS, etc. often attract scientists and engineers from other institutions to perform their work/investigation at these facilities. Even the Tevatron, when it was operational, had huge number of physicists from other places, very much like the way CERN/LHC is right now.

So kids, don't aim your ambition to work for a particular employer or location. Aim for the type of profession that would be able to perform the task that is involved in working at that location.

Zz.

Particle Physics Is Worth Funding

I wasn't going to comment on this article, but I decided to anyway.

This appears to be an opinion piece for a college newspaper at Oklahoma University. It has some minor issues that do not detract from the central message of the article. The author is presenting a case on why something as esoteric as particle physics is worth funding.

Sounds interesting, but laypersons are not amateur physicists, and want to know the practical benefits of what their dollars are funding.

The difficulty with this reasoning is it ignores how the nature of science operates. Albert Einstein did not anticipate his theories of relativity would play a prominent role in GPS satellites and smartphones. The discovery of quantum mechanics, perhaps the most esoteric of the sciences, would ultimately give rise to conductors and computers. Virtually all of electricity can be traced to research conducted in the 19th century that was thought to have little, if any, practical benefit. Many of the machines found in hospitals such as MRI’s are based upon principles of physics discovered by physicists who had no interest in medicine. In order to properly do science, even the most abstract subjects need and deserve funding.

This certainly is true, and a message that I've posted here many times.

The minor issues I have with this article are:

(i) the technical aspects of it, especially when he said" ... The discovery of quantum mechanics, perhaps the most esoteric of the sciences, would ultimately give rise to conductors and computers..." when I think he meant "semiconductors". The discovery of QM did not give rise to conductors, because we already know about Ohm's law and everything else about conductors well before QM was formulated. We even know about semiconductors before then. We just don't know the physics of semiconductors.

(ii) the "references" being used are often other news articles. This is fine IF you are commenting on that news article (like what I often do in this blog). But if one wants to have proper citation to back one's claim of either science or a fact, using a news article is equivalent to passing on a piece of gossip. We have seen how news articles can often skewer something, or even get it totally wrong. So not a good idea to depend on such sources to justify one's opinion.

There's also something interesting here. The article is written by a philosophy major. On one hand, it is too bad someone with a physics background (a physics major) did not write this. I mean, who else is more qualified to try and sell to the public why they would fund what they do? I'm guessing such a person would not commit the two issues I listed above. But on the other hand, having someone else trumpets the importance of what we do, someone without a direct financial, vested interest, might carry more weight. Having a non-physicist urging for support for particle physics might certainly be a novel effort that might get more attention. I don't know.

The article missed a few other important reasons why particle physics is worth funding. I mentioned one important aspect of it earlier where particle/high energy physics experiments drives innovation and technological advancement in the area of detectors. Again, it is worth repeating that while most other areas of science construct and design their experiments based on equipment that they can buy commercially or that are available on hand, high energy physics often can't do that. This is because many of the detection and things they want to do, and the accuracy/resolution/speed that they need, have not been invented. So what they end up doing is to innovate and invent their own devices and detectors. This innovation and technological advancements eventually trickle down to other areas of physics, science, and the general population. And this area of detectors is just one example. One only needs to look at their computing needs and how much data they have to handle to know that they are also doing unbelievable innovation in terms of data transfer, handling, computing needs, etc. Don't tell me other companies are not observing and learning from this very carefully.

And speaking of detectors, if you wish to further check up on my claim of particle physics innovation in this area, check out the proceeding from the 2nd International Conference on Technology and Instrumentation in Particle Physics (TIPP 2011). Papers are available for free. Bookmark it. I can guarantee you that a few of these that were designed for particle physics experiments will directly impact our lives in the next decade when they are used in other instruments.

Unfortunately, here in the US, funding for high energy physics continue to decline. The impact on this to the US intellectual activities, innovation, and economy can only felt once it becomes too late.

Zz.

"From Aether Theory To Special Relativity"

This could easily be a condensed intro to Special Relativity. If you are not familiar with it, or want a quick historical overview, you might want to check out this article.

Zz

RF Basics

This is the course material for class in RF fields used for particle accelerators, given at a CERN Particle Accelerator school.

Note the very important characteristics of this course. You'll see the beginning of the material looking like a typical E&M course for a physics major. But later on, you'll see the applications of it the way an electrical engineer would see it. This is a clear example of what I've been trying to emphasize so far, that this is one of those fields where physics and engineering smoothly merge! It is why the field of accelerator physics is one of the few areas of physics that still has a higher hiring rate and why graduates can find a wide-range of jobs to apply for beyond just academia.

Zz.

Physicist Gave A Paper Marriage Proposal

I'll admit it. Physicists can be a bunch of rather weird, strange people. But hey, no one can ever accuse us of not being creative! After all, who would have come up with proposing to one's future wife by putting it into a physics paper?

When Sydney physicist Brendan McMonigal got down on one knee to propose to his partner of seven years, Christie Nelan, he pulled out a physics paper, not a ring.

His paper, Two Body Interactions: A Longitudinal Study, pictured right, is laden with science geek speak and tracks the couple's relationship, including a graph (''happiness over time'') and the all important question.

It helps that the future bride is also a physicist, so she got the meaning.

I found a copy of the so-called paper elsewhere on the web. Best wishes to the happy couple!

Zz.

How Big Is the Universe?

Check out the video. You are the center of the universe... the observable universe, that is.



Zz.

Ernest Moniz Leading Candidate For DOE Post

The rumor that we have been getting is that MIT Physicist Ernest Moniz is the leading candidate to replace the retiring Steven Chu for the Secretary of the US Department of Energy (DOE). This makes for another physicist being selected to run that branch of the Federal Govt.

The leading candidate to replace departing energy secretary Steven Chu is Ernest Moniz, director of the Energy Initiative at the Massachusetts Institute of Technology (MIT) in Cambridge. He would bring to the office a pragmatic support for nuclear power and natural gas, along with a candid desire to, in his own words, “innovate like hell” on basic energy technologies. Colleagues at MIT are waiting for a confirmation of the appointment, which could come as early as this week. “Ernie is a real people person, and he took us to a whole new level in terms of both size and visibility,” says Howard Herzog, a participant in the Energy Initiative who works on carbon capture and sequestration technologies at MIT.

From that news article, it certainly appears that Moniz might be able to better navigate the politics of Washington, since he has had plenty of experience dealing with that kind of cra... err ... environment before.

If this comes true, I would be happy enough. I was dreading the idea of a non-scientist, a non-engineer, or worst still, a career bureaucrat, running what is essentially a science/engineering/technical branch of the govt. We have had those before with other administrations. I'd rather not have that again.

Zz.

Possible Higgs Has Strong Even Parity

CMS and ATLAS continue to investigate the particle discovered last year that are strong candidates to be the Higgs. The latest result out of CMS is the study of the parity of this particle.

One important test is the parity of the particle: how its mirror image behaves. In a mirror, even-parity particles look the same, whereas odd-parity particles appear reversed. The standard model Higgs boson is a scalar, a spin-0 even-parity particle. But there are many models that include a spin-0 odd-parity particle known as a pseudoscalar.

Turns out that the result points strongly towards the even-parity particle, which is consistent with the Standard Model Higgs.

Zz.

Open Access For All Federally-Funded Papers

The US White House has released a policy directing all federal agency to make available to the public all federally-funded research work.

The six-page directive from the White House Office of Science and Technology Policy (OSTP) says that agencies that spend more than $100 million on research must "develop a plan to support increased public access to the results of research funded by the federal government," including papers published in peer-reviewed journals. Each agency must come up with a draft plan within 6 months that meets several requirements. For example, it must leverage existing archives, strive to partner with journals, make it possible to access digital data, optimize the ability to search and archive papers, describe how to enforce compliance, and find ways to carry out the plan within the agency's existing budget. 

Not sure how the for-profit journals would deal with this, but for many not-for-profit journals such as the Phys. Rev., authors are already allowed to put copies of their publications either on their own webpages or on arXiv.

Zz.

ILC And CLIC Unite

Not a very surprising news since almost everyone saw it coming. The two groups that are working on the next generation of linear collider to follow the LHC as CERN have decided to join forces and share information in a new organization.

The two most mature future particle physics projects, the International Linear Collider (ILC) and the Compact Linear Collider study (CLIC), have formed an official organisational partnership today. As the newly founded Linear Collider Collaboration, they will coordinate and advance the global development work for the linear collider, a global project to complement the Large Hadron Collider (LHC) at CERN and ultimately understand the deepest secrets of the universe. The Linear Collider Collaboration is headed by Lyn Evans, former Project Manager of CERN’s Large Hadron Collider (LHC). Hitoshi Murayama, Director of the Kavli Institute for the Physics and Mathematics of the Universe, will serve as a deputy director.

Of course, for ILC, this is certainly welcomed since the US is severely cutting back on its contribution to the ILC effort (some even say that the ILC in the US is dead). It also appears that if some form of the ILC is built, Japan appears to be the leading candidate for a site to build this facility. For those of us in the US, this means that the US will continue to have ZERO high energy physics particle collider if this comes true.

Zz.

A Tour Of MIT's Plasma Physics And Fusion Center

If you haven't seen the inside of it, here is a quick tour of MIT's Plasma Physics and Fusion Center.

Zz.

New Limits On Possible (?) 5th Force

OK, I'll be honest. I am not quite sure how I would tackle this news release, because I could easily go off the deep end and just blast this thing to bits. First of all, this is a fine work, and I haven't finished reading the paper yet. So the issue here isn't with the published work. But I have issues with this press release.

This press release describes a very novel way of looking for a possible spin-spin force, using the entire earth (?) and invoking a multidisciplinary knowledge.

Hunter -- along with emeritus Amherst physics professor Joel Gordon; postdoctoral fellow Stephen Peck; student researcher Daniel Ang '15; and Jung-Fu "Afu" Lin, associate professor of geosciences at UT Austin -- co-authored a paper about their work that appears in this week's issue of the journal Science. The highly interdisciplinary research relies on geophysics, atomic physics, particle physics, mineral physics, solid-state physics and nuclear physics to reach its conclusions.

The way this has been titled, and the way it sounds, it makes it sounds as if there is a 5th force, and that we're just trying to hunt it down. All this experiment has done is put a severe limit on such a thing because of a non-detection at the level of accuracy that the experiment has. In other words, they didn't find any!

But what I found unbelievable is the comment from one of the authors.

Lin had his own take: "The most rewarding and surprising thing about this project was realizing that particle physics could actually be used to study the deep Earth."

Whoa! Is this really that surprising? We already have studies on geoneutrinos, among other things. It all came out of our knowledge from high energy physics.

Oh well, I guess we can add this to a GROWING list of practical applications of high energy physics.

Zz.

Robert Richardson Dies at 74

This is on the news almost everywhere, but I'll report it here anyway in case anyone missed this. One of the giants in the world of condensed matter/low-temperature physics has passed away due to complications from a heart attack. Richardson won the Nobel Prize in Physics in 1996 along with Douglas Osheroff and David Lee for the discovery of superfluidity in He3.

You may also read the NY Times coverage of this here (link available for free only for a limited time).

Zz.

Incorporating Technology Into A Physics Lab Course

Quite a while back, I asked about useful physics apps that people are using on their smartphones and tablets. This blog entry covers something similar, but a bit more specific.

We all know that a lot of students in college (and even in high schools) nowadays have laptops, tablets, and smartphones. In fact, in some schools, they give out tablets to incoming freshmen as part of their registration package. Of course, these things are often used to browse the web, and maybe be even useful to take down notes in class. Still, I was thinking of some other ways that these items can be useful, and the one area that I think should be explored (if it hasn't already) is in the college physics laboratories.

There are already discussions going around on various research projects migrating to electronic lab books. I still haven't seen detailed description on how that is implemented, how it works in a collaborative environment, and how people keep them secure and archived. But the tell-tale signs are there, that this might easily be the wave of the future. So I believe that, as physics instructors, we should prepare the students for such an environment, and introduce the ability to migrate from our traditional pen-and-paper lab notebooks to the electronic version.

I have been exploring a few apps on my iPad on whether such a thing can be done in a college physics lab class. I first started out with a number of criteria that it must be able to do, based on what I expect from the students:

1. The students must keep their own lab notebook. They can scribble anything here, from notes taken during lab briefing, to notes taken during the experiment itself.

2. The record needs to be "permanent". In a traditional paper-and-pen lab book, all records must be written in ink. No erasing of anything.

3. The students will then use these notes to write a proper lab report that will be submitted (electronically, of course) along with the lab notes.

The only way that I can think of for the students to do their note-taking quickly and efficiently is to use apps that accept free-hand writing, using a stylus for convenience. It will allow them to quickly jot things down as if they are writing on paper, it allows them to make quick sketches, and also easily draw up a table when taking data. In other words, it will work just like a pen-and-paper situation.

However, the drawback here is that, unlike ink on paper, what they write and draw are not permanent, and there will always be a tendency to try and erase things off a page. While I can try to keep on drilling into their heads to not do that, there's nothing to absolutely prevent such an act. The only way I can think of to minimize them changing what they wrote in the lab is to require them to send whatever lab notes that they have done at the end of the laboratory session to me, via e-mail. That way, whatever they have written by the end of the experiment is now permanently stored in my record and can't be changed. I can always refer to these notes when reviewing/grading their lab reports.

So far, the apps that I've been testing and like the most is an iPad app Penultimate. With a stylus, it is quite easy to write notes, draw stuff, and make tables, all the things that I need to do in a lab. Each experiments can also be its own separate notes, so at the end of the lab, the students can easily just e-mail that to me. What is also nice about this app is that it can be synched to Evernote, another app. Evernote is an app that works under iOS, Android, and also a program that can be run under Windows and Mac. Once you synch items in Evernote, those items are accessible to all your devices that are running your Evernote. It is extremely convenient, you don't have to keep sending things around or e-mailing yourself documents. In this case, once you send your lab notes to Evernote, then when you get back home or to your room, if you have a desktop or laptop, you can always fire up Evernote, pull out your lab notes, and start writing your report. The apps is also useful when you have a collaborative effort with someone else, but I've yet to test that out extensively.

I haven't tested this out yet in a lab class because I am still trying it out on my own. But since the reader of this blog comes from such a varied background, I thought I throw this out in case some of you are already ahead of the curve and already are implementing such a scheme in your classes/laboratories. I would very much like to hear from you and what your experience is in doing something like this.

Edit: has anyone use LabGuru iPad app? This is something I'm interested in hearing and will be testing soon. But if you have used it, or are using it, I definitely want to hear from you.

Zz.

Physics Professor's Bizarre Behavior

Hey, I am all for engaging students attention in a physics class, but I think this went too far and was extremely bizarre. A professor at Columbia University pulled off a very strange stunt in front of his students, and apparently did not give any rational explanation on why.

First-years in Frontiers of Science were supposed to hear a lecture on quantum mechanics from renowned physics professor Emlyn Hughes on Monday morning. But what they witnessed first was a bizarre performance from Hughes that left many of them baffled and confused.
As students filed into the lecture hall, all of the lights were off, except for two spotlights on stage where Hughes was sitting. With Lil Wayne's “Drop It Like It’s Hot” playing in the background, Hughes stripped down to his underwear, then proceeded to change into a black T-shirt and pants. Afterwards, he sat down on the chair, hugging his knees in a fetal position.
Then, as a jumbled video that included footage of the planes crashing into the Twin Towers on 9/11 continued to play on the screen, two figures dressed in black came on stage with long swords. One of them proceeded to chop a stuffed animal in half on a stool.

Ok, that is downright creepy. But then again, if anyone tells you physicists are boring and uninteresting ........

Zz.

Breaking Time-Reversal Symmetry Reduces Thermodynamic Efficiency

This was reported a few days ago, but I've only had a chance to read it recently. It is an interesting calculation for the thermodynamic efficiency of a thermoelectric engine in the presence of an external magnetic field, thereby breaking the time-reversal symmetry.

In this spirit, Kay Brandner at the University of Stuttgart, Germany, and colleagues report in Physical Review Letters their calculated efficiency of a simple thermoelectric device that converts heat to electrical current (Fig. 1). They show that when the device operates in an external magnetic field—a condition that breaks time-reversal symmetry for the motion of electrons—the efficiency is significantly lower than previous studies predicted. The lower bound on efficiency occurs, they argue, because in addition to the requirement that entropy be greater than or equal to zero, charge must be conserved—a point that was missed in earlier work. Their findings improve our understanding of thermoelectric efficiency and may one day influence the design of thermoelectric devices for real-world applications.

The rest of the article has a very good detail on why this is such an important study. You also get a free copy of the paper in the link.

Zz.

It is Valentine's Day - Date A Scientist!

(A tip of the hat to Ryan at PF for finding this amusing article)

If you are single, and you find that you can't stand all this brouhaha about St. Valentine's day, then I found an article that is a perfect solution for you - date a scientist!

Scientists are highly educated people with decent career prospects, but are also rarely associated with a fondness for romance and passion (or any other emotional state) so are likely to be apathetic towards Valentine's Day. Ergo, scientists are the ideal partners.

There ya go!

The article then went on to tell you a good way to snag one of these elusive scientists.

Happy hunting!

Zz.

Vote For Your Favorite PhotoWalk Photos

Voting has started for you to vote on your favorite Particle Physics PhotoWalk contest. There are some stunning photos in here, and I don't know how I can choose just 3.

So get your votes in!

Zz.

Science At Work

A rather fascinating video out of Fermilab. In some ways, this is a "propaganda" video, but in other ways, it actually is a very informative look at not only what the Lab does (or will do), but also what "high energy physics" is. The personal angle that is included in the video provides some "emotional" content that the general public can relate to.

Here's the synopsis of the video:

Six days. Three frontiers. One amazing lab. From 2010 to 2012, a film crew followed a group of scientists at the Department of Energy's Fermilab and filmed them at work and at home. This 40-minute documentary shows the diversity of the people, research and work at Fermilab. Viewers catch a true behind-the-scenes look of the United States' premier particle physics laboratory while scientists explain why their research is important to them and the world.

It's a long, 40-minute video, though. But it is worth sitting down and watching it, especially if you want to learn a bit more about high energy physics here in the US, and what Fermilab did and will do.



Zz.

FFAG Review

I wrote quite a while back about this Fixed Field Alternating Gradient accelerator, including the unfortunate acronym that it has adopted. This document provides a good review of this area. It was presented at a 2011 CERN Accelerator school.

Zz.

"Quantum photonic devices in single-crystal diamond"

A very interesting report on the ability to control single-photons in photonic devices.

Physicists in the US are the first to make an integrated device that extracts photons from a tiny piece of diamond before the light is sent through a waveguide to the outside world. The photons all have the same frequency and originate in a nitrogen vacancy (NV), which is a defect that occurs in diamond when two neighbouring carbon atoms are replaced by a nitrogen atom and an empty lattice site. According to the researchers, the chip could be used to create quantum-information technology such as quantum repeaters.
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Researchers are particularly interested in extracting photons that do not interact with the surrounding lattice because these "zero phonon line" (ZPL) photons have a well defined frequency. Unfortunately, one challenge in building NV-based quantum systems is how to reliably get ZPL photons out of the diamond and into an integrated optical system, where it can be processed further. What Andrei Faraon and colleagues from Caltech, Hewlett Packard and the University of Washington have managed to do is to create an integrated optical system that does just that.

You can get free access to the paper at the New Journal of Physics website.

Notice that this work was partly funded by DARPA.

Zz.

Kelvin Probe

Hey, I'm an experimentalist. It may be a revelation to some because I see this blog linked to many different sites, and some of them referred to it as ".. written by a high energy theorist..."! Me? High energy theorist? :)

Anyhow, I think it is always good to highlight certain experimental techniques, especially the ones that I'm quite familiar with. So here's one.

Often, for most of us, our first encounter to measuring the work function of something is via the photoelectric effect. Later on, if some of us go into photoemission spectroscopy, we deal with the work function there as well. However, that is not the only means to measure the work function. A technique that does not require the use of any light source to perform such measurement is called the Kelvin probe.

If you understand the physics behind a pn junction in semiconductors, then you've already understood the physics used in a Kelvin probe. You have a metal (the probe) with a particular Fermi energy, in close proximity (or in contact) with another material that has a different Fermi energy. This creates a contact potential difference. The Kelvin probe measures this contact potential difference, which is the difference between the two Fermi energies.

The link that I gave above gives you more details on such a measurement. If you know the value of the Fermi energy of the probe, you get the value of the work function of the material being studied. The only caveat here is that if the sample you are looking at is a semiconductor, you do not get the "work function", but rather, the value of the Fermi energy with respect to the vacuum state. In many cases, this is called the work function (energy between the Fermi level and the vacuum state) of the semiconductor, but one should not confuse this with the photoemission threshold, because the Fermi level resides in the gap. The photoemission threshold is the energy between the top of the valence band and the vacuum level.

Confused? Let's go on.

A significant improvement in the Kelvin probe technique was introduced with the invention of the Atomic Force Microscopy (AFM). It turns out that one can adapt an AFM system to work in the Kelvin probe mode. This technique is now called Kelvin Probe Force Microscopy (KPFM). I've linked to a very nice review paper on the physics and capabilities of KPFM technique. This technique allows for the mapping of the surface potential (or work function if you know the work function of the tip) of a surface with spatial resolution of the order of 100 nm.

So why is this useful. Obviously, knowledge of the surface potential is crucial in the understanding of the behavior of many materials (read some of the references in the KPFM review paper). It is another parameter that is part of the characteristics of the material. It also provides another check to the value of the work function that are often obtained from photoemission experiments. In fact, some material actually react to the exposure of light (especially UV), and the value of the work function obtained may not be as accurate as it should be from photoemission measurement.

There. So now, if you haven't heard about this before, you've learned something new! :)

Zz.

No Ignition For National Ignition Facility

The soft whispers about issues and skepticism with the National Ignition Facility (NIF) got louder with the review reports on its failure to meet its milestone last year.

The US$3.5 billion National Ignition Facility (NIF), at the Lawrence Livermore National Laboratory in Livermore, California, is designed to crush tiny pellets of hydrogen isotopes until they fuse into helium. The goal is to release more energy than goes into the pellet and in doing so roughly mimic conditions inside a modern nuclear warhead.

That was the goal, but a six-year “ignition campaign” came up short in September, sparking introspection amongst scientists, federal officials and congressional funders. Introspection in Washington inevitably leads to reports, and in November and December, a series of reviews of the project were released—including plans to shift the giant laser facility away from ignition work and towards weapons.

The gist of the conclusion given in the committee report is in this paragraph:

The important conclusion from the NIC is that the pressent understanding of the physics of the hahlraum and capsule implosion as embodied in modeling and computer simulation is insufficient to predict the results of the implosion experiments aimed at achieving ignition. Reviewers indicated that, while progress towards ignition had been made, a program of scientific experiments and modeling focused on understanding the various physical effects, in isolation, that impact the integrated implosion experiments provides the best approach to eventually either achieve ignition, or to understand definitively why it may not be achievable with indirect drive using the NIF laser. Executing such a program will also require enhancing the number of diagnostic measurements of both the future focused experiments and integrated implosion experiments.

The ignition program certainly has a major task ahead of it, and this failure to initiate ignition certainly generates even strong skepticism of its program.

Zz.

70 Years Of Schrodinger's "What Is Life?" Lectures

If you were not alive 70 years ago, this news article provides a very good summary of the landmark set of lectures by Erwin Schrodinger on a surprising topic for a physicists - What is Life?

One of Schrödinger's key aims was to explain how living things apparently defy the second law of thermodynamics – according to which all order in the universe tends to break down. It was this that led my colleague Professor Brian Cox to use Schrödinger as the starting point of his BBC series Wonders of Life, leading to What is Life? shooting up the Amazon sales chart.

But Schrödinger's book contains something far more important than his attempt to fuse physics and biology. In that lecture 70 years ago, he introduced some of the most important concepts in the history of biology, which continue to frame how we see life.

I'm wondering if many crackpots and creationists got the idea of the evolution of life violating the 2nd law from this lecture. It might easily be the impetus for such misinformation to be passed on.

Anyhow, this is a very good news article to get a brief idea on that monumental lecture in the history of science.

Zz.

Store Photons. Then Make Them Intract With Each Other

It's amazing to see the development in this area. Just a few years ago, we were amazed at the accomplishments coming out of Lene Hau's lab in being able to not only store photons, but also to "replay" them back. Now comes this, which is another step in refining and improving the capability of storing photons.

What Charles Adams and colleagues at Durham University have now done is come up with a way of storing individual optical photons in highly excited states of an atomic gas. Once stored, the photons can be made to interact strongly, before being released again. An important feature of the technique is that it uses microwaves, which are also used to control some types of stationary qubit. 

 http://arxiv.org/pdf/1207.6007v3.pdf

Apparently, this is to be published in PRL.

Definitely a commendable accomplishment here in the evolution of our capability of using photons for quantum communications.

Zz.

The Emergence Of QCD

This is a nice review of how QCD came about and its role in the Standard Model, written by Nobel Laureates David Gross and Franck Wilczek.

Zz.

Steven Chu Resigns

In case you didn't see this already, Steven Chu announced his resignation as the US Energy Secretary.

Chu will enter the record books as the longest-serving Secretary in DOE's 35-year history, and the first Nobel laureate to lead the sprawling, $27 billion department. Once a successor is named, Chu says that he plans to return to California. He spent 17 years on the faculty of Stanford University before moving to the University of California, Berkeley, and was director of DOE's Lawrence Berkeley National Laboratory before coming to Washington in January 2009.

Despite the Solyndra debacle, I thought he did an admirable job considering that he was faced with a hostile congress that was determined to cut funding to the sciences regardless of the harm it will do not only to the advancement of knowledge, but also to the US economy.

It will be interesting to see who President Obama will nominate to replace him. I'm hoping that it will be someone who is a scientist and not a science-challenged bureaucrat (cough bill richardson cough!).

Zz.

A Laser-Based Table-Top Neutron Source? I'll Take One!

Exciting news for those who depend on neutron sources for to study things. A new development in using high-powered laser to produce energetic neutrons with reasonable flux has been reported.

Neutrons are a valuable tool for scientists in many fields, allowing them to probe the structure and dynamics of a range of materials. Today, the main drawback of neutron science is that intense beams of neutrons must be produced in either nuclear reactors or dedicated accelerator facilities – making a laser-based table-top source very attractive.

This scheme has now been put into practice by Markus Roth of the Technische Universität Darmstadt and colleagues at Los Alamos and Sandia National Laboratories. Roth's team directed extremely powerful and well defined pulses from the Los Alamos TRIDENT laser onto a 400-nm-thick plastic target doped with deuterium atoms. This was positioned just 5 mm in front of a secondary target made from beryllium.

Even though the pulses delivered less than a quarter of the energy employed in previous experiments, they produced neutrons that were nearly 10 times as energetic – up to 150 MeV – and also nearly 10 times as numerous. In addition, many of these neutrons were emitted in the forward direction, which the researchers attribute to one specific kind of nuclear reaction, the break-up of deuterons.

This has the potential to either replace, or supplement spallation neutron sources. There's still a lot of work to be done, but it looks like this could make having neutron source for material study as easily has having x-ray sources for such a study. Of course, we haven't considered the safety issues here since neutrons are significantly more dangerous to deal with here.

Zz.

RHIC In Danger Of Being Shut Down

In operation for only about 12 years, the Relativistic Heavy Ion Collider at Brookhaven is in danger of being shut down, due to budget shortall for DOE's Nuclear Physics division.

A panel of scientists has recommended shutting the last U.S. grand atom smasher, the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory in Upton, New York, to make room in a tight budget for other projects funded by the Department of Energy (DOE).

Closing RHIC would be a disaster for the U.S. nuclear physics community, says Robert Tribble, a nuclear physicist at Texas A&M University, College Station, who chaired the committee that suggested doing exactly that in a report today to DOE's Nuclear Science Advisory Committee (NSAC). "I don't think there are winners and losers here," he says. "We're all losers if this comes to pass." NSAC is expected to approve the report tomorrow, and DOE has usually followed such recommendations from its advisory panels. 

While this is a sad news, it is not unexpected, considering what the panel had to deal with, especially when faced with the 2 new construction projects that they had to consider.

The Tribble committee weighed the relative importance of three very different facilities. RHIC uses twin accelerators to smash heavy nuclei together to produce fleeting puffs of a weird type of matter called a quark gluon plasma that filled the newborn universe. In contrast, DOE's other existing major nuclear physics rig, the Continuous Electron Beam Accelerator Facility (CEBAF) at Thomas Jefferson National Accelerator Facility in Newport News, Virginia, fires electrons into protons and neutrons to study their inner workings. In addition, physicists plan to build a $615 million Facility for Rare Isotope Beams (FRIB) at Michigan State University in East Lansing that would generate myriad exotic nuclei usually produced only in supernova explosion.

Researchers are currently finishing a $310 million upgrade to CEBAF, and the committee recommended exploiting that investment, Tribble told NSAC. That forced the group to choose between continuing to run RHIC, which has been collecting data since 2000, and building FRIB, which could start taking data by the end of the decade. The committee included representatives from all three projects, says Tribble, who declined to give the vote tally.

As has been said, we are all losers if this facility shuts down.

Zz.

Quantum Biology

I had mentioned already on the emerging connection between quantum mechanics and some aspects of biological phenomena (see here, here, and here). This BBC science article reviews the current effort to use quantum mechanics to explain some of the biological effects.

The most established of the three is photosynthesis - the staggeringly efficient process by which plants and some bacteria build the molecules they need, using energy from sunlight. It seems to use what is called "superposition" - being seemingly in more than one place at one time.

Watch the process closely enough and it appears there are little packets of energy simultaneously "trying" all of the possible paths to get where they need to go, and then settling on the most efficient.

You may read the other examples that they gave in that article. But what irked me slightly is what was mentioned near the beginning of the article.

Disappearing in one place and reappearing in another. Being in two places at once. Communicating information seemingly faster than the speed of light

This kind of weird behaviour is commonplace in dark, still laboratories studying the branch of physics called quantum mechanics, but what might it have to do with fresh flowers, migrating birds, and the smell of rotten eggs?
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Until recently, the delicate states of matter predicted by quantum mechanics have only been accessed with the most careful experiments: isolated particles at blisteringly low temperatures or pressures approaching that of deep space. 

That is utterly false, because our modern electronics are the proof to counter that. QM isn't restricted to such esoteric conditions. QM is what is responsible for our iPhones, iPads, computers, MRI, electron microscopes, flat-panel TVs, PET scans, etc... etc. Sure, to be able to observe the "weird" behavior of QM, we will have to go to extremely difficult conditions, but the description of QM are directly used for many everyday items and process. After all, this is what the biologist here are trying to do as well, use the description of QM to explain observed, macroscopic biological phenomena.

BBC News science section needs to get rid of this myth quickly. It undermines the usefulness of QM.

Zz.

Update On the Mansuripur "Paradox"

I had mentioned the rebuttals that this "paradox" has been getting ever since it appeared. Science has an updated review on the status of this thing and has essentially declared it solved.

Mansuripur is sticking to his guns. He argues that hidden momentum, which was identified in the 1960s, is an ill-defined concept that merely papers over the problem. "That's always been the problem with hidden momentum," Mansuripur says. "You know that something is missing, so you just postulate its existence." He says his approach eliminates the need for hidden momentum.

Others say that hidden momentum is part and parcel of relativity. "If you have a system with internal motion that is subject to an external force, then hidden momentum is a general property," says Daniel Vanzella, a commenter at the University of São Paulo in São Carlos, Brazil. "It's not an ad hoc invention put in to reconcile things." Vanzella also notes that mathematically, the Lorentz force law can be written in a form that guarantees it will jibe with relativity, so it's "simply impossible" for it to contradict the theory.

There was a question towards the end of this article on whether this should have been published or not. I see no problem in it getting published (although, I don't think it should have been in PRL). Mansuripur clearly found something intriguing that needed to be sorted out. It was not done out of deceit and it was definitely a legitimate question. The rest of the community then responded in kind to correct what they see missing or in error. That's what this whole publication process is supposed to do, and this is how it should work. Publication never guarantees validity.

Zz.

We Don't Need No Stinking Theory Of Everything!

This is a Q&A with Lisa Randall.

The reason why I'm highlighting this is that the questions being asked is the type of questions many of us faced with we talk to the public. The very first question, for example, is rather typical:

Doesn't every physicist dream of one neat theory of everything?

Of course not! But the public has a very narrow idea of what physics is. Many are surprised when I tell them that the largest percentage of physicists in the US are working in the area of condensed matter/material science, which is not the first of study that directly involves the Higgs, high energy physics, string, etc. So for many of us, this "theory of everything" isn't something we dwell on that much, not to mention, there are even prominent physicists who think that this "theory of everything" is a myth.

In any case, this article covers some of the common questions that we often see.

Zz.

Immovable Object vs. Unstoppable Force

As stated in the video, I too have seen such a question being asked on the internet numerous times. And as can be seen in the video also, question like this is often asked without clearly think of what the question actually means. This is important in physics because the question that we ask can sometime be as important as the answer that we get. So having a clearly defined question is crucial.



Zz.

"I Want To Ride My Bicycle, I Want To Ride My Bike...."

Bicycle! Bicycle!

Yes, we are doing bicycle physics! I already mentioned about this quite a while back. But there's new coverage on this not-as-simple-as-you-think phenomenon of riding a bicycle. The new coverage doesn't present anything new, though, but merely reemphasize the fact that 'steering' is an important factor in how one can balance on 2 wheels on a moving bicycle.

Partially through this research, physicists have come up with an explanation for why bicycles don’t tip over: they always turn toward the direction they’re falling. When the bicycle begins to tilt to one side, the front wheel turns in that same direction, which prevents the bike from falling over. This can be verified by locking the handlebars so that the bicycle can’t turn. When you do this and give the bike a push, it topples over.

Now, the reason why the bicycle steers in the direction that it is about to topple over isn't as clear.

That’s where things get really complicated. Rather than a simple explanation, scientists have developed a formula that determines whether or not a bicycle design will have this essential attribute. Insomuch as it has been tested, the formula works. Unfortunately, it’s not a simple two- or three-variable equation: it requires 25 different characteristics of the bicycle to make a prediction.

So do we know how a bicycle works? Technically, yes. We have an equation that can predict whether or not a particular design will be easy to balance. But that doesn’t mean we fully understand what’s going on and the one-sentence explanation of what keeps it upright only leads to more questions that aren’t so easily answered.

So there! Even the everything, common thing that we all are familiar with can still be puzzling.

Zz.

Dance The Higgs

Ah, another one of those!

I made no bones about my feeling on such things. This appears to be another attempt at incorporating physics into the arts. In particular, they're incorporating the apparent discovery of the Higgs into dance and photography.

Our Reintegrate project will translate the details of the Higgs boson discovery into a series of precisely choreographed visual images. By translating potentially the greatest breakthrough in particle physics in the 21st century through the intersecting artistic mediums of photography and dance, we will investigate the problem and benefits of communication across three disciplines that weigh heavily toward the non-verbal articulation of ideas.

 First of all, I don't quite understand exactly what is meant by the phrase that I've bold in that paragraph. Secondly, since we're "talking" about non-verbal articulation of ideas here, I would like to challenge the organizers to try this experiment: DO NOT tell your audience in advance what the dance is about. Don't even give them a title (thus, the non-verbal part). Just present the dance. After the presentation, do a poll and see what they think the dance is about. What are the chances that they actually will say "Oh, it is about the problem and benefits of communication across physics, dance, and photography on the discovery of the Higgs boson"?

Now, you could ask me "But ZapperZ, arts, such as dance, is very subjective and interpretive. You don't expect them to actually come up with not only an accurate answer, but also one consistent answer, do you?" And I would say, that's my whole point! If you want to communicate about the discovery of the Higgs, the importance of the physics of the Higgs, etc., your BEST BET in doing that is to convey an UNAMBIGUOUS message is via direct, verbal communication! It cannot be done effectively and unambiguously via "dance". I just don't see it.

If you want to do this simply for entertainment, fine. Knock yourself out. But I seriously question when this thing is being "intellectualized" as if such an exercise can actually produce anything meaningful, informative, and accurate. This is just too close to being an Emperor's New Clothes to me. A lot of people are going along with the "intent" but there hasn't been a lot of substance.

Zz.

Physics Is Fun?

I've posted something on this topic before, and I'll continue to do it. I always like to highlight classes and/or teachers that go beyond what they have been asked to do and try to make a physics lesson more interesting and more engaging to the students. This is one such example.

Montgomery's physics class is certainly not what one would think of as a traditional classroom.

Yes, there are lectures. Yes, there is homework. But there's also a lot more that this group of seniors gets to experience.

"The fun thing about older kids, they're still kids," she said. "They just want to play."

I also like the observation that she had on her students.

The hands-on activities help students relate to what they are studying. But even that doesn't always make it easy.

"They still struggle. When you go to paper and pencil, it helps that they have that interest. But they have to apply the math," she said. "Physics is hard."

In the past, almost no one took physics at the high school level. Until the State of Ohio stepped in and gave it a boost.

"They made it so you have to have physics to get an honors diploma. Our numbers practically doubled after that," she said. "They might not be excited to take it, but they find something about it that is interesting to them."

Being that the class is generally made up of some of the brightest students in the senior class, Montgomery said the students don't always deal well with struggling to understand the difficult subject matter.

"They still think that because they're good at everything else, they expect to get every question right the first time," she said. "I still have to go back and look at questions more than once sometimes."

As we all had to do if we're in education.

Zz.

So I Am Your Intro Physics Instructor

{I wrote an essay on what I would say to my student if I were his/her academic advisor. Since this is the beginning of the semester for many schools (or the beginning of the school year in parts of the world), I thought it would be appropriate for me to "publish" another "speech". This time, I'm directing it to a class of  intro physics students.}


Dear Students,

Welcome to the intro physics course. For many of you, this is your first college level physics course that you are taking. Hopefully, it will lay the foundation for the rest of your undergraduate education and becomes something that you will find useful.

I would like to let you know of some of my expectations from you, and would like to let you know of what you can expect from me. I know that many of you are taking this course because you have to, not because you want to. I am also aware that the majority of you are not physics majors. However, I hope to impress upon you why you would want to do well in this class. Besides the fact that it will affect your overall GPA, I want to make you aware that there are a lot of things you can learn and acquire from this class that will be very useful to you not only in your academic pursuit, but also in other parts of your life later on.

The most important point I want to make is this: while the material that we will be covering is important for you to understand to do well in this class, what is equally important is the ability in analyzing a problem that you are faced with, and figuring out how to systematically solve it. I want you to pay attention not only to the content of the course, but also to how I approach a problem and how I go about solving it. I will try to teach you the physics and also the problem-solving technique. I will try, as best as I can, describe to you what I'm thinking when I look at a problem, and how I analyze it to know what to start with and how to proceed.

Keep in mind that while this is something that I can attempt to teach you, it really is a skill that you can only acquire after repeated practice. It is very much like learning how to ride a bike. I can tell you what to do, but you'll never gain the skill to ride a bike until you have practiced several times, and taken a tumble here and there. The homework that you will have to do is meant to be your vehicle to practice on to acquire such skill.

At some point, you may question why we are studying certain things, or why we are trying to tackle a certain type of problem. One example that I can bring up is the projectile motion that you will see and have to solve till you're sick of it. You may find it strange that we are asking you to solve various configurations of the projectile motion problem. Are we trying to train you to be an artillery person? No.

You see, I could teach you that F=ma and then walk away. There. We've covered a huge section of our semester already. Now, go use that to build me a house. Chances are, you can't. What you've received is only a superficial knowledge. You may know the relationship between F, m, and a, but you don't understand how it is used or how it can be applied. Knowing how to do that will give you knowledge beyond the superficial level. So we try to apply F=ma in a number of examples. Unfortunately, the examples that we can use that are simple enough are limited. We can't exactly apply all the real-life conditions to an example because it will them make the problem too complex, and you will be thoroughly confused. You will be distracted by the complexity and lose the focus on how F=ma is applied. So we have to deal with simplified examples on how we use F=ma, and this is where examples of projectile motion, motion of objects sliding on inclined planes, etc.. come in. We are not trying to turn in you experts in artillery or building a slide. You should not be focusing on the nature of the example. You should be focusing on the aim of these examples, i.e. how F=ma is applied.

Now, because I want you to understand both the material and the technique, you should not hesitate to ask me questions if you do not understand anything. This is especially true if you do not understand why, in solving a problem, I would do such-and-such, or how I know to start with such-and-such if it is not obvious to you. It is important that you make sure you understand things every step of the way, because we will be building on you learn early in the semester and apply it to more complex situations later on. If you start with a shaky foundation, you will not be able to master the material that you will be faced with later in the semester. So please, ask me questions in class, or come to my office hours. I have been paid to serve you and impart knowledge and skills. Make use of this opportunity.

My last advice to you here is that the process of learning is a very private, internal activity. While you have your texts, your notes, your instructor, etc. to help you, in the end, it is YOU who have to make the effort to acquire such knowledge and skills. It must sink in for you. At some point, you have to figure things out for yourself. It means that you need to understand things on your own, and be able to do your own thinking. You have to figure our how you understand things and what you need to do to get something.

And this is where this physics course can be of a tremendous value to you, not just for your future academic pursuit, but in your later life. To put it bluntly, you will consciously learn how to think and how to analyze a problem. You will learn to what degree you can say that A causes B, and how can you figure out what affects what. This ability transcends a physics class and will be extremely useful to you as you become a responsible citizen.

I hope you have a productive and enjoyable time in this class. Now let's get to work.

Zz.

"Quantum Information And Randomness"

If you haven't come across this yet, don't miss it. This is a very good review of what is essentially the most comment topic in Quantum Mechanics - randomness that is inherent in the standard interpretation of QM. The co-author of this article is Anton Zeilinger, so you are getting some of considerable authority on the subject. The review on the Bell-type experiments are excellent - pay attention to why this doesn't violate SR.

Zz.

"How many dominoes does one need to topple a domino as tall as the Domtoren?"

Supposedly, that was a question in a 2012 Dutch Science Quiz.

Anyone who has followed this blog for any considerable period of time would know that I love reading and studying about mundane phenomena and physics, and this one qualifies as one. PhysicsWorld is reporting a study appearing on ArXiv recently to answer that very question.

The Domtoren is a 112-m-tall cathedral tower in Utrecht and the idea is to begin with a standard-sized domino, which topples a larger domino. This then topples an even larger domino and so on until a Domtoren-sized domino can be felled. The process is called "domino multiplication" because a tiny tap on the first domino can, in principle, topple a huge monolith. Now, Van Leeuwen has calculated the upper limit on how much larger each successive domino can be. In principle, his calculations suggest that the maximum ratio of successive domino heights can be about 30% larger than the widely accepted value of 1.5. 

Of course, he had to make some simplification to his model:

But in the real world not all that energy is channelled into bringing down the next domino in line. First off, the dominoes bounce a little as they strike one another. Next, they have a tendency to slip along the surface they are stood on as they are nudged, lessening the chance of a fall or causing them to fall back towards the striking domino. And finally, once in contact, they drag against one another as they fall.

In his model, Van Leeuwen simplifies the situation by assuming that the collisions are completely inelastic, that the friction between the dominoes and the surface they stand on is infinite, and that the dominoes, once touching, experience zero friction and simply slide over one another. 

And of course, there's a video demo, but it isn't related to this particular preprint:



Fun!

Zz.

Misconception of the Heisenberg Uncertainty Principle - The Video

Back in 2006, I wrote an entry on the misconception of the Heisenberg Uncertainty Principle. I used light going through a single slit to illustrate what the HUP really is.

Now, I've found a video illustrating JUST THAT!



I hope that with the video, what I was trying to explain is even clearer than before.

Zz.

The "Brian Cox Effect" In The UK

I've heard about this from last year where the enrollment in physics degrees in the UK has seen a significant surge, but this one kinda reinforce it.

Manchester University is the first in the country to require students to gain two elite A* grades – alongside an A – at A-level to get onto its physics degrees.

It represents the highest entry threshold for any physics course in Britain, including those run by Oxford, Cambridge, Durham and Imperial College London. It is among only a handful of degrees in any subject nationally to demand two A*s.

Manchester has always been a popular choice for physics but the university admitted that a recent rise in applications had been partially driven by the attraction of Prof Cox, one of the department’s academics and presenter of television series such as Stargazing Live and Wonders of the Universe.

The news report went on to also include the LHC/search for the Higgs as also being partly responsible for the sudden popularity of physics.

I hope this is all good. Like I have said before, physics is too difficult to do for the wrong reasons. I hope that the LHC and Brian Cox are providing inspiration and new pathways that many students just simply didn't think of before, rather than just being enamored by the "celebrity" and "sexy news of the day".

Zz.

Physics And Sports

I've had many posts on here on how physics is applied to sports. This video presents a lecture on the relationship between physics (classical mechanics) and sports/games. It appears that this was given just before last year's London Olympics.



Zz.

Video of the Launch Control Center

A while back I posted photos of my visit to the Kennedy Space Center in Florida. I mentioned in that trip report of the rare visit to the Launch Control Center (or Firing Room), which is normally not opened to most people, much less, the public.

I've put raw video footage of that visit to the LCC on YouTube in case anyone wants to take a look at it. I've done no editing of any kind to it (thus the "raw" description). You'll get to hear a little bit from the tour guide in the background in some shots, but other than that, there's no narration.



Zz.

Linking A Particle's Mass To Time

This is rather surprising and unique.

A paper to be published in Science claims to have made a clock that measures time by linking it to a mass.

Abstract: Historically, time measurements have been based on oscillation frequencies in systems of particles, from the motion of celestial bodies to atomic transitions. Relativity and quantum mechanics show that even a single particle of mass m determines a Compton frequency ω₀ = mc²/ ħ, where c is the speed of light and ħ is the reduced Planck constant. A clock referenced to ω₀ would enable high-precision mass measurements and a fundamental definition of the second. We demonstrate such a clock using an optical frequency comb to self-reference a Ramsey-Bordé atom interferometer and synchronize an oscillator at a subharmonic of ω₀. This directly demonstrates the connection between time and mass. It allows measurement of microscopic masses with 4 × 10⁻⁹ accuracy in the proposed revision to SI units. Together with the Avogadro project, it yields calibrated kilograms. 

That's definitely an astounding accomplishment if this is verified. They actually could somehow get at the frequency associated with a particular mass.

A news report on this work can be found here, which reveals a bit more of the issue surrounding this measurement.

The idea for the clock stemmed from the quantum principle that particles also behave as waves, and vice versa. In particular, Müller and his colleagues wanted to determine how frequently the wave form of a single atom oscillates, a quantity that in quantum mechanics is inherently linked to the atom’s mass. Then the researchers could use those oscillations like swings of a pendulum to create a clock.

The snag in Müller’s plan was that it’s impossible to directly measure the oscillation frequency of waves of matter. The frequency of these waves is about 10²⁵ hertz, 10 orders of magnitude higher than that of visible light waves. So Müller and his colleagues came up with an apparatus that creates two sets of waves — one based on a cesium atom at rest and another on the atom in motion. The researchers measured the frequency difference between the waves and then used that number, a manageable 100,000 hertz or so, to calculate the much larger oscillation frequency of cesium at rest.

Let's see this will work out.

Zz.

Physics - The Second Most Demanding Major?

We have had reports before on studies or surveys that convey the idea that physics is a difficult subject. Some would even say it is the most difficult subject.

This blog post on Physics Central reports on a survey of students of various majors. One of the survey question is on how much time the students spent per week studying the subject. Physics majors came in 2nd, just behind engineering, in the number of hours per week studying the material.

According to a survey of hundreds of thousands of college students in the U.S. and Canada, 36 percent of physics seniors spend 21+ hours preparing for class every week. Only one other group out-studied the physics majors: engineering students. 42 percent of engineering seniors devoted 21 or more hours to studying every week.

There are more to the survey than just this, so you can read the rest either in that blog, or from the actual survey itself.  And you can draw your own conclusions from them.

Zz.

LHCb Result Published

Hey, remember when I highlighted the recent result from LHCb where it could not find any hint of anything beyond what the Standard Model predicted? The paper on the result has now been published in PRL and you can get free access to it from the link in this review.

Zz.

How Not To Teach Physics?

This is an interesting article written by former U. of Ottawa professor Denis Rancourt (you may want to read a bit of his history with his former university). Certainly, article that appeared on this Dissident Voice webpage consistently challenge the establishments and the established notion. I have zero issues with that. However, I question the validity of many conclusions, especially when it is only backed by anecdotal evidence. And just because someone questioned the conventional way of doing stuff does not make him/her immune from being equally questioned for the conclusion he/she is drawing.

Rancourt wrote on how ineffective the standard method of teaching physics is at imparting physics knowledge to students. Certainly, there have been plenty of studies to indicate that such dull methods of teaching is not every effective. He then described how he did it is own way and how, in his opinion (and the opinion of his TA), it showed an improvement.

I told the students to close their books and not read them, unless they thought they might find something of interest in there that they wanted to know. I told them they could look anywhere they wanted and ask anyone questions to find what they wanted.

I told them that first we needed to figure out what was worth knowing, and what it means to know.
I got blank stares. They worried about how they would be graded in such a system. They wondered what I really meant and what did I want them to do. But they gave me a chance and, luckily, I didn’t know what I was doing, so it was quite authentic.

So I said: “Let’s see. There must be every day things that we want to know, that we can understand…? Things we are curious about?”

They couldn’t find any. Some of them said they had a lot of work to do in their other classes so they did not want me to be too demanding. Many shared that view. But as the conversation continued and as it became clear that, well, it was a conversation; they relaxed. But they still could not think of anything they wanted to know, beyond the latest homework in the other courses. Sad really.

So I said: “Why is the sky blue?” “No really, how does that work?”

Well many of them had heard something about that in high school so we started a class-wide discussion about how and why the sky is blue. And for every answer that did not quite work, we were able to find a flaw in the answer, or a dead-end, where the word answer was not really explaining anything beyond “something something”.

I told them that it maybe had something to do with why the evening sky can be red and also asked why clouds are white, when they are not red.

So this led us to what is light…? Now you can spend a lot of focused time asking yourself what light is if you want to know why the sky is blue. So I discovered… I helped them see, through questions, what it was to truly know or understand something versus just repeat the words… that they could search and explore and critique themselves. So they did.

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And we had a final examination. And, honestly, it was like no final examination I had ever seen before. It was the opposite of depressing and fun to grade. It was full of intelligence and independent thought and evidence of significant research. I had a sense that the students had understood things, could explain them, and owned their knowledge.

I went back to the previous year’s examinations and saw a huge difference. I lent the two piles of examinations to the TA and she concurred that, yes, there was a significant qualitative improvement that could not be denied.

Now know that I was not comparing “bad” teaching to “anything would be better than that”. I was considered one of the best traditional method teachers, by the usual standards. So I was comparing certified bad teaching to something much better.

Now, there's a number of issues here that were not tackled:

1. Many physicists today were taught using the "conventional" methods. I was one of them. While one can argue that these may not have been the best technique, one cannot argue that WE, as a group, didn't learn any physics from them. In fact, I will vehemently argue that my E&M instructor was one of the best teacher that I've ever had and left his permanent imprint on me on how I learn things in physics. He taught things in a conventional means, but he was damn good at it. So then, is the problem here the philosophy of teaching, or the EXECUTION of that philosophy, i.e. how such conventional teaching is presented? Was Rancourt's ineffectiveness  in making the student learned early on a problem of the philosophy of teaching, or was it because he simply was not a good teacher executing that philosophy or methodology? I'm not saying he isn't, but this is something we don't know.

2. How effective is his new "technique"? Sure, anecdotally, he could claim that the exam results were better. But this is not how we arrive at things in science. Educational research requires quite a number of sampling, testing, and controlled groups for comparison. One simply can't claim one has discovered something better simply via such anecdotal evidence.

3. Note that other countries, especially Asian countries such as Korea, Singapore, and China, have continually produced masses of students that have tested higher in math and science. As far as I can tell, their teaching and learning techniques are still heavily "conventional" and not approaching anywhere near what Rancourt is doing. So why are these kids able to learn and understand physics?

I fully understand the desire to do things differently. After all, I've written extensively on how I would revamp the undergraduate intro physics labs to fulfill various goals. However, until that is properly tested, I would not make any kinds of claim of its effectiveness, because I'll just be doing what I've criticized a lot of people have done - relying solely on anecdotal evidence before proper, scientific and more-verified evidence are available. And people who dissent should not be quick to dissent by lowering their standards of what can be accepted to be valid.

Zz.