Wednesday, August 31, 2011

Teaching Radioactivity

A series of videos from the Institute of Physics (IoP) that teach elementary radioactivity.


Tuesday, August 30, 2011

Would You Use A Physics Digital Textbook?

With more and more universities and schools accommodating the use of tablets for their students, many textbooks publishers are beginning to migrate their books to be used on one of these devices. Certainly, right off the bat, one can see a convenience factor in not having to always carry these books, especially the heavy ones (Halliday and Resnick, anyone?).

The pain points of traditional print edition textbooks are obvious: For starters they're heavy, with the average physics textbook weighing in at a burdensome 3.6 pounds. They're also expensive, especially when you factor in the average college student's limited budget, typically costing hundreds of dollars every semester.
Even if it is just nothing more than an exact pdf duplicate of the textbook pages, it probably be something worthwhile IF it costs considerably less than the printed books. This of course, is not a guarantee since the price of electronic books and novels appear to be rather high so far.

Still, I think they can do a lot of more useful things for the electronic books version of physics texts. The most obvious ones would be to include videos, etc. as demos for various physical principles being discussed. One could even include a brief video of a lecture that corresponds to that particular topic in the chapter.
But the thing that I would like to see the most is a "live illustration" of examples being worked on. In most textbooks, examples are necessary to illustrate how a particular principle is used and applied. I don't know about you, but this is how I tend to learn and understand a particular topic. So I always want to see examples. It would be nice if the electronic text comes with an example that is worked out live, very much like having a private tutor sitting next to you and showing you how to solve a particular problem. I envision a blank page where the particular problem appears at the top, and then a voice would come on and start laying down the approach in solving the problem. What is the question asking for? What principle or idea is relevant? Where should we start? Why do we start here and not there? The text then draws a diagram (if necessary, which it usually is when tackling physics problems) and then writes down a general equation that is the starting point. It then solves it, showing step-by-step operation as it goes along, with an audio accompaniment, just as if someone is right next to you showing you how it is done.

As a bonus, it would be nice to include other ways to solve the problem. For example, in solving a projectile motion problem, we often can pick many different locations for specifying the origin of our coordinate axes, and even what direction we designate as positive, etc. It would be nice if the electronic text can show different ways to solve the same problem so that it gets drilled into the student that a lot of these things are arbitrary, but you still get the same answer in the end. Doing this in print text would be tedious (and would kill even more trees).

Electronic textbooks are still in its infancy. Maybe in a few years, we get might start to see some of the astounding capabilities that it can do.


Monday, August 29, 2011

Experimental Test of Airplane Boarding Methods

Back in 2008, I reported a rather interesting (at least, to me) use of some of the techniques from statistics and physics to find the most optimum boarding method onto an airplane. This study was done purely via mathematical modeling. Of course, being physicists/scientists, just having a model isn't enough. One has to verify it.

Now come a report whereby the author of that original paper and others have done an experimental study various methods of boarding an airplane.

Abstract: We report the results of an experimental comparison of different airplane boarding methods. This test was conducted in a mock 757 fuselage, located on a Southern California soundstage, with 12 rows of six seats and a single aisle. Five methods were tested using 72 passengers of various ages. We found a significant reduction in the boarding times of optimized methods over traditional methods. These improved methods, if properly implemented, could result in a significant savings to airline companies.

I would say that airlines such as Southwest could learn quite a bit from this study, since they have such a short turn-around time for their airplanes.

And I love it when there's a follow up to a study such as this.


Saturday, August 27, 2011

SUSY In Deeper Trouble

Supersymmetry is already not having a good year with the current non-discovery at the LHC from the ATLAS and CMS detectors. This theory is already in trouble with those results. Now it is in a deeper trouble, because another LHC detector, LHCb, has announced its result, and NADA!

This failure to find indirect evidence of supersymmetry, coupled with the fact that two of the collider's other main experiments have not yet detected supersymmetic particles, means that the simplest version of the theory has in effect bitten the dust.
 If this is true, this could be one of the most spectacular failure in theoretical physics in quite a while. A whole "cottage industry" has been built around supersymmetry, and many students have gotten PhDs in it. But more importantly, let this be a lesson to anyone coming up with theories that have yet to be verified, or can't be verified by any reasonable means in the foreseeable future. You hear that, string theorists?


Hurricane Physics

With Hurricane Irene bearing down on the east coast of the US right this very minute, the rest of us who have the luxury of not evacuating or worrying about it can follow its progress and also understands a little bit of the physics associated with such weather phenomenon.

In any case, our thoughts are with those who are enduring, or about to endure this storm.


Friday, August 26, 2011

Neutrinos and Antineutrinos - Maybe Not So Different After All

The latest report out of the MINOS experiment seems to pull back a bit from their earlier report of the difference between neutrinos and antineutrinos mass oscillation.

“This more precise measurement shows us that these particles and their antimatter partners are very likely not as different as indicated earlier. Within our current range of vision it now seems more likely that the universe is behaving the way most people think it does," said Rob Plunkett, Fermilab scientist and co-spokesman of MINOS. “This new, additional information on antineutrino parameters helps put limits on new physics, which will continue to be searched for by future planned experiments.”
 Hum... so are they "correcting" their earlier paper?


Thursday, August 25, 2011

A Simple Explanation of The Standard Model

Maybe you haven't understood what is meant by "The Standard Model" of particle physics, or haven't come across a simple explanation of what it is. Well, this could be your lucky day.

This looks like a straight forward, simple explanation of the Standard Model of particle physics. I may have a little quibble about it here and there, but other than that display of the very long Lagrangian, you should be able to follow that is being said here without needing to have a background in a lot of physics.


Tuesday, August 23, 2011

So I Am Your Academic Advisor?

Dear Student,

I am honored that you chose to work with me as your graduate advisor. Obviously, this is a mutual agreement between us since I also chose you as my student. I hope that we have a productive and beneficial collaboration together as you pursue your PhD degree.

I would like to convey to you some of my expectations, goals, plans for you so that you will have a better idea on what to expect. I would also like to tell you what you can expect from me, and maybe you can also tell me what your expectations are. Hopefully, they overlap a lot, and we have a mutual agreement on what these next few years will entail.

My goal for you is not only to impart knowledge so that you become an expert in a particular subject matter, but also to train you to be a physicist. This means that you not only will know the subject very well, but you will also be able to present it, both verbally and in writing, to be able to know the economic constraints that comes in doing physics, to know how to find funding, to have a feel on what's interesting and what's important, and to be able to become a respected citizen physicist. Furthermore, I want to equip you with skills and knowledge so that by the time you graduate, you have a large degree of "employability", that your ability to find a job is not constrained to just academia.

Since you chose to work for me, you will be doing a lot of experimental work. Many of these are hands-on work that will involve learning, maintaining, and constructing vacuum systems. You will have to learn how various vacuum components work, how to handle them properly, how to assemble them, how to design and maintain such system. You may also end up learning several experimental technique, diagnostics, equipment, procedure, etc.. etc., some of which may not even be in your thesis. However, these are skills and knowledge that might land you a job. Your knowledge in many of these areas are relevant not only to a life in academic research, but also in many private, high-tech companies if you choose to pursue that line of employment.

I expect you to do a lot of background reading. I will give you a few material as starting point, and you must use any and all resources available to you to find the necessary material to help you to understand what you are reading. Don't be surprised if you end up having to read several papers each week. At this point, as you become familiar with the subject matter, you must also be very familiar with the state of knowledge of that subject matter. What do we know now? What is the direction of research that this area is heading into? What are the things we don't know? Who are the "big names" in this area? Finding out the answers to all of these will take a lot of time. I will guide you and direct you to certain resources that I think you should know. And you are more than welcome to come and talk to me if you have questions. However, the responsibility in learning these things on you.

As you develop your skills and knowledge in this field, at some point (sooner rather than later, hopefully), we will both decide on what your thesis area of research will be. Ultimately, it is my decision on what area you should pursue since officially, I will have to give the department my approval. Still, I hope this is a topic that you will also find suitable since you chose to work with me.

As you gather results and as we discover new knowledge, I expect you to learn how to publish your work. I will guide you on where we should publish, but you should start paying attention to how we decide on what to publish, and where to send for publishing. These are crucial decisions that you will need to get a feel on as a practicing physicist. I will also send you to several conferences where you will present your work in front of your peers and other physicists. I want you to gain confidence in presenting your work, and to acquire skills in oral presentation. This is something you have to do several times before you gain your confidence, and before you get a hang of it. I will help you by having you give several practice talks before you present your actual talks. You will learn what you did right, and what you did wrong, and hopefully learn from them.

You are expected to attend the department's seminar if time permits, especially if it is in the same area as your study. However, you should make an attempt to attend all seminar. It is to your benefit to know what is going on in other areas of physics. You just never know if you have to make a switch in subject area during your career, the way I did. It is never a waste of time to gain knowledge of things you didn't know before.

As you get closer to writing your thesis, we will sit down together and narrow down what exactly you will cover. No doubt that we will go through several iterations before we end up with the final product. You will again do a practice defense in front of me and a few other graduate students. Hopefully, by then, you also would have attended the thesis defense of other graduate students in our department, so you should know what to expect.

By the time you graduate, you and your family should rightly be proud of your accomplishment. I know I will be. I will be more than happy to provide you letters of recommendations for the next chapter in your career. If you find this experience rewarding, and if you end up in a situation where you are mentoring students of your own, remember your experience as a graduate student just starting out with your ambition of pursuing your dreams. If you think that I've treated you fairly, with respect, and that I've tried to equip you with the necessary knowledge and skills to turn you into a productive physicist, then I hope you will pass it on to your students and those you mentor.

When you get to do that, then it is at that point that I have successfully done my job as your "Academic Advisor".


Monday, August 22, 2011

A Place To Look for Majorana Fermions

This is one of those rare endeavor where both the high energy physics community and the condensed matter physics community are looking for the same thing but with different experiments. They are both looking for tell-tale signs of Majorana fermions but using entirely different scales of experiment. The high energy physics community is looking at remnants from particle physics collisions at huge particle accelerators, while the condensed matter physics community is looking at very small experiments using topological insulators. Who will find it first?

My bet is on the condensed matter physics. This report is another reason why these physicists might have a leg up, because one possible area where they might want to look has been narrowed down. A new theoretical paper indicated that the superconducting vortices on a topological insulator might contain these elusive Majorana fermions.

It is then natural to ask, What is a doped topological insulator good for? While one hopes that many of the topological phenomena of the true insulating state might be manifested in some form in a doped system, many questions still remain unanswered. However, Hosur et al. have made a striking prediction that MBS can still be realized in doped topological insulators under certain mild conditions. A true insulating state is important in the Fu-Kane proposal because if the bulk contains low-energy states then the MBS can tunnel away from the surface and delocalize into the bulk, which effectively destroys the MBS. Hosur et al. circumvent this delocalization by requiring that the entire doped topological insulator become superconducting. They show that as long as the doping is not too large, vortices in superconducting topological insulators will bind MBS at the places where the vortex lines intersect the material surfaces. While this might seem like a big leap in complexity, experimental evidence already shows that, indeed, copper-doped Bi2Se3 is a superconductor below 3.8 K. In this context, Hosur et al. make a strong prediction that vortex lines in superconducting CuxBi2Se3 can harbor MBS.
 (MBS=Majorana bound state)

These topological insulators are definitely a playground for a lot of exotic states that most people typically associate with elementary particles in QCD/QED. This is another example where the so-called "applied" physics of condensed matter can be a source of very fundamental physics.


Higgs Signal Fading?

The latest report from a conference in Mumbai, India, is reporting that the Higgs signal that was reported barely a month ago is fading with more data.

A five sigma signal means the chance of the result being a statistical fluke is less than one in three million. Since July, the Higgs-like signals seen by the CMS group have fallen from around 2.8 to 2.3 sigma. Those seen by the Atlas group have dropped from around 2.8 to less than two.

We're still waiting for the combined data from CMS and ATLAS.  I'm guessing that they don't want to fall victim to background issues that could be the major culprit of the "bump" seen in the CDF data that no one else is seeing.


Sunday, August 21, 2011

The Student's Apparatus That Shut Down Omaha's Airport

Remember earlier this month on the incident whereby a student returning from a conference shut down the Omaha, Nebraska airport due the suspicious nature of the demo apparatus that the student has in the luggage? We now have more details on what it was.

The physics apparatus works similarly, but instead of sampling a person's blood (via their finger), the LEDs measure the light absorbed by two different liquids. First, the experiment calls for a green LED to be shone through a small, clear container filled with a chemical indicator called bromothymol blue. The bromothymol blue represents oxygenated hemoglobin.

A voltmeter or multimeter measures the change in intensity of the light. Then, another liquid, an acid solution representing deoxygenated hemoglobin, is measured. The bromothymol blue should absorb more of the green light than the acid solution. The test is repeated for both liquids using a red LED. The experiment mimics how a pulse oximeter measures the oxygen saturation in a person's blood.

From the photo, I can see why someone might mistaken it for a homemade explosive device. So kids, let this be a lesson. Before you bring some physics items with you onto a plane, look at it. I mean, REALLY LOOK AT IT! You could cause a lot of grief to other people.


Saturday, August 20, 2011

An Atheist In A Church

When I first read this news, my first reaction was "Oh, that Unitarian Church in Pueblo, CO is rather ballsy to invite not only an atheist to present a talk on God and Science, but also to invite someone of Vic Stenger's stature to present that talk". Either this is a trap, or they are really open-minded bunch of people! :)

Well-known atheist author and scientist Vic Stenger will speak at 3 p.m. Sept. 17 at the Unitarian Universalist Church of Pueblo, 110 S. La Crosse Ave.

The title of his program is "God and Science." Admission is free and the event is open to the public.

Stenger's best-known book is the New York Times best-seller, "God: the Failed Hypothesis: How Science Shows that God Does Not Exist." His most recent book is "The Fallacy of Fine-Tuning."

I already mentioned about Stenger's book "God: The Failed Hypothesis". And no, I still haven't managed to read it yet. In any case, I certainly would like to be a fly in that room when this talk is delivered. Anyone by chance planning on going? I'd appreciate a brief report!


Friday, August 19, 2011

Pioneer Anomaly Is Getting Smaller

In a work that is arduous and tedious, Slava Turyshev and colleagues have done an incredible job of analyzing data from Pioneer spacecrafts. They came to a conclusion that the anomaly is getting smaller, and thus pointing to a more conventional explanation for the origin of such anomaly.,

Evaluating this painstakingly compiled trove of data, the team confirms that the Pioneer anomaly is real. However, they find that the anomaly is slowly diminishing, although they cannot say whether the decrease is linear or exponential. They also find that it's impossible to say whether the deceleration points toward the Sun or toward the Earth.

A decreasing anomaly offers renewed support for the idea that the craft experience small forces because of the way their complex shapes reflect and radiate waste heat. Turyshev and his colleagues are now finishing a detailed analysis of heat emission to see whether it could have the magnitude and direction needed to explain the anomaly.

I'm sure we'll hear more about this.


Thursday, August 18, 2011

Physics Is Cool Again?

This article reports on the increase in enrollment in physics classes in the United Kingdom and presents the case that maybe studying physics is "cool" again.

The total number of students entered for physics A-level has increased by 6.1%, from 30,976 in 2010 to 32,860 in 2011. Applications for physics courses at university are also up by more than 17% on last year and astronomy is up by a whopping 40%.

Commentators believe that this increase is partly due to students thinking more about their future employment prospects - but some suggest that the surge in interest is that physics has become "cool" again.

The article offers several reasons for this increase, among which is the "Cox Factor", attributed to Brian Cox and his "geek chic" image. But essentially, no one knows why.

Still, this statistics is consistent with the latest statistics in the US as well that shows an increase in physics enrollment. Maybe we're on to something. Or maybe it's in the water....


The Physics of Coffee Rings

Here's another example of the "mundane" curiosity that I love very much.

This time, it is on the coffee rings that we typically see after a drop of coffee dries. And the physics is important enough, and has important applications, that something that appears as mundane as this gets published in Nature, no less.

The edges of a water drop sitting on a table or a piece of paper, for example, are often "pinned" to the surface. This means that when the water evaporates, the drop can't shrink in circumference but instead flattens out. That flattening motion pushes water and anything suspended in it, such as coffee particles, to its edges. By the time the drop fully evaporates, most of the particles have reached the edge and are deposited on the surface, making a dark ring.

There's also a video that accompanies this:


Wednesday, August 17, 2011

Cuprates - An Overview

This is a very good review article on the theoretical aspects of the high-Tc cuprate superconductors, and why it is such a complex system that a single accepted theoretical description still evades us after 20 years of its discovery. I actually had a chuckle when I read the end passage of the article:

Regardless, magnetic correlations definitely play a prominent role in the entire doping range superconductivity is observed . Whether this means RVB, spin fluctuations, orbital currents, or some combination thereof, such magnetic correlations are the likely source of d-wave pairing. But building a rigorous strong coupling theory has certainly proven to be a challenge. Perhaps ideas from string theory and black hole physics will help in this regard. But then again, perhaps not!

Ooooh boy! :)


Tuesday, August 16, 2011

Daya Bay Is Up And Running

A major neutrino experiment has started to take data. Daya Bay, which is stationed in China, is the first major collaboration where the US and China are equal partners.

At its inception the Daya Bay Experiment broke new ground as the first equal partnership between the U.S. and China on a major high-energy physics project, leveraging monetary support, technical expertise, and intellectual contributions from over 40 institutions in collaborating countries around the world. Initial U.S. participation was guided by James Siegrist, Associate Laboratory Director for General Sciences at Berkeley Lab and Director of the Physics Division.
There's a tremendous amount of physics that can potentially come out of this experiment. With several other neutrino experiments going on, and about to come online, neutrino physics is as exciting as what is being done at the LHC.


Monday, August 15, 2011

STM Images Molecular Orbital

Scanning tunneling microscopy has been extremely useful in condensed matter/material science. Now, it might finally be an important tool in chemistry. A new report shows a very neat experiment using a STM with a tip that has been "functionalized" with a CO molecule. So in this case the tunneling goes through the p-wave orbital of the molecule and allows for an imaging of the nodal direction.

With their new results, Gross et al. show that combining CO-functionalized tips and alkali-halide interlayers allows them to image the nodal pattern of the orbitals of flat organic molecules (Fig. 1). Here, again, the two CO 2π* orbitals play an important role. These derive from the p orbitals of the carbon and oxygen atoms that stand perpendicular to the molecular axis. Figure 1 shows one of the 2π* orbitals: it has four lobes (drawn in red and light blue, representing their phase or sign) separated by two nodal planes. The other 2π* orbital, perpendicular to the one in Fig. 1, is not shown. By bringing the tip close to a sample molecule (pentacene in Fig. 1) separated by a salt layer from a metallic substrate, and tuning the voltage between tip and substrate to address a particular orbital of the pentacene molecule, the lobes of the CO 2π* orbital and those of the pentacene orbital (shown in purple and rose) come into and out of registry, as the tip is scanned across the molecule.

Amazing work. You can get the paper for free at the link above.


Saturday, August 13, 2011

Man Goes Through Small Inner Tube - Impossible Physics?

Besides being hilarious, this could be a fun "problem".

A man who obviously has a "girth" larger than the inner radius of a floating inner tube, appears to have gone through it unscathed, both for him and the inner tube.

Or did he not go through the tube since he took the inner tube down with him?

Still, assuming that he did, how did he get through? The human body is soft enough (specially around areas with lots of ... er .. padding) that one could squeeze through something like that.

What do you think?

Credit: CBS News


Bosons and Fermions

Want to know what bosons and fermions are in simple terms, without any misspellings? This article gives it to you in very "simple" terms.

The difference between them is just spin. But in this context, spin is a quantum number of angular momentum. It is a bit like the particle is spinning, but that is really just an analogy, since point-like fundamental particles could not spin, and anyway fermions have a spin such that in a classical analogy they would have to go round twice to get back where they started. Quantum mechanics is full of semi-misleading analogies like this.

Regardless, spin is important.

Bosons have, by definition, integer spin. The Higgs has zero, the gluon, photon, W and Z all have one, and the graviton is postulated to have two units of spin. Quarks, electrons and neutrinos are fermions, and all have a half unit of spin.

There! You are now ready to work on a QFT problem! :)

All kidding aside, sometime it is handy to have a simple, laymen-level explanation. One would hope that this will lead to more questions and more attempts at understanding.


20th Anniversary of e-print ArXiv

If you've been in this field since the early 90s, you would be extremely familiar with the e-print ArXiv. This repository has undergone quite an evolution, and has transformed how physics works. It turns 20 this year. Its founder, Paul Ginsparg, wrote a fascinating article in Nature on how this simple website has revolutionized communications between physicists.

Within a few years it had evolved into a web resource at that now contains close to 700,000 full texts, receives 75,000 new texts each year, and serves roughly 1 million full-text downloads to about 400,000 distinct users every week (see graphs). It has broadened, first to cover most active research fields of physics, then to mathematics, nonlinear sciences, computer science, statistics and, more recently, to host parts of biology and finance infiltrated by physicists.

However, what is interesting here is that, while physicists don't really have that big of an issue with sharing work that has not yet been published, researchers in other fields are not as enthusiastic.

Physicists were quick to adopt widespread sharing of electronic preprints, but other researchers remain reluctant to do so. Fields vary widely in their attitudes to data and ideas before formal review, and in choosing to share electronic preprints, each community will have to develop policies and protocols best suited to their users. A talk I gave in 1997 to a group of biologists helped catalyse the resource now known as PubMedCentral — run by the US National Institutes of Health. I served on the initial advisory board, which soon decided not to host any unrefereed materials, even carefully quarantined, in part for fear of losing essential publisher participation. There remain many legitimate reasons for individual researchers to prefer to delay dissemination, from uncertainty over correctness, to retaining extra time for follow-ups, to sociological differences in the way publication is regarded — in certain fields, the research somehow doesn't count until peer reviewed.
 ArXiv is an amazing resource, and in some areas of physics, such as high energy/particle physics, it is almost as important as peer-reviewed journals.


Friday, August 12, 2011

The Physics Of Ultrasonic Cleaning

As someone who uses ultrasonic cleaning quite often, it is fascinating to me that we are still learning on what actually goes on when we put something in an ultrasonic cleaner. This study, published in PRL no less, examines the physics of how things actually are cleaned on the surface using an ultrasonic cleaning process.

In some experiments, the researchers coated one side of every bead with gold, so they could see the beads' rotation. The beads rolled back and forth during a single cycle of the bubble's expansion and contraction, some at a rate corresponding to 150,000 rotations per second. This rapid rotation implies a large twisting force (torque) on the beads. The torque arises because the beads rest partially in a thin, stationary layer of fluid at the glass surface and partially in the fluid above, which moves rapidly in response to the bubble. "The rotation is a very clear indication that this boundary layer is important," says Ohl. Similarly, in ultrasonic cleaning, a dirt particle stuck to the surface will extend partly out of the boundary layer and feel a large torque that can break its connection to the surface.
The link also has a video of the action.


Thursday, August 11, 2011

Ions Entangled Using Microwaves

In what is claimed to be a major breakthrough, ions have been trapped and entangled using microwaves for the first time. Supposedly, this is significant because one can deal with microwaves in electrical circuits, and certainly easier than using optical frequency lasers.

Two independent groups of physicists have made important breakthroughs in the control of quantum computers based on trapped ions. Instead of controlling quantum bits (qubits) using multiple laser beams, the teams have used microwave sources, which are much easier to control and integrate within quantum circuits. The work could lead to practical quantum computers that incorporate large numbers of qubits on a single chip.
Progress is often made in small steps. This is another example of it.


Wednesday, August 10, 2011


It seems that the LHC has also gotten into this distributed computing stuff. They are looking for idle computers (such as yours when you're not using it) to do some distributed computing. Can't guarantee that your computer will be hunting for the Higgs, but maybe it might run some code to do some Monte Carlo background simulation! :)


Tuesday, August 09, 2011

Insurance Advertisement Fails Physics

I had quite a chuckle reading the blogs on this Farmer's Insurance advertisement. I didn't see the advertisement before, so this is my first time being aware of it. But still, I wish I had seen it.

I suppose the biggest blunder in the figure is that the symbol "s" was used as distance, yet in the figure, the various values of "s" were given units of "m/s". So that certainly is a rather dubious mistake.

The other part where the trajectory of the pig (cow?) is not quite parabolic, that I'm not that picky about (you should read the link above and see how this is analyzed in detail). A sketch on a blackboard is often "not to scale" or highly accurate (look at the asymmetric roof line on the house).


Monday, August 08, 2011

No Sign Of "Eternal Universe" Yet

It appears from these latest publications, we do not have any detection yet from CMB of collisions from "bubble universes" (didn't know we were looking for them).

Stephen Feeney at University College London and his colleagues analyze seven years of cosmic microwave background data from the Wilkinson Microwave Anisotropy Probe (WMAP) to hunt for signatures of eternal inflation.

They find no signatures of collisions, but are able to use this null result to put an upper limit on the number of bubble collisions the theory could predict and still be consistent with the data.

Oh well. I'm sure we'll continue to hunt for them!


Saturday, August 06, 2011

Physics And The Peril Of Airline Flights

This was bound to happen, and something I fully expected.

This report gives an account of an amusing (at least for those of us not delayed by such a thing) incident at the Omaha, Nebraska airport. It seems that a student's demonstration equipment became a suspicious item and caused the airport security to go on high alert.

According to an article from the Omaha World-Herald, the Omaha Police Department's bomb squad was called to the airport's Terminal B just before noon on Wednesday to attend to a "suspicious-looking item" in a carry-on bag. Screening was halted and the B concourse was evacuated, the World-Herald said, though operations in the airport's other terminal remained unaffected.

The newspaper reported that, according to an FBI spokesperson, an Oregon college student's science project was the culprit. The student had been at the AAPT meeting and had submitted his or her project in the meeting's apparatus competition. After about two hours the suspicious items were deemed safe and the airport was cleared, but nine flights were delayed as a result.
Honestly, I'm not surprised by this. I've had many occasions where I could have brought along several equipments with me onto the plane, and I chose not to. Things such as photomultiplier tubes, multimeter, vacuum components, etc.. etc. may not look at ominous to those of us who know what it is. But to those who don't, they could easily trigger as a "suspicious items", since they are not really a common items that they encounter. So yes, in all of these cases, I always had them shipped, rather than bringing them with me either in my carry-on or checked luggage. The last thing I want is for something exactly like this to happen. It may not cause any legal implications, but man, it causes a lot of headaches, delayed flights, and very annoyed people.


Early Career Town Hall

One of the more productive effort done in my US National Labs is trying to train and nurture early-career scientists, especially in ways that they can seek research funding. So there are many lectures, seminars, workshops, etc. that are organized and targeted to young scientists at these labs to help them to this by learning from other senior scientists who have had successful funding of their programs.

This is one such lectures given at Berkeley Lab. The lecture focuses on the lab's Laboratory Directed Research and Development (LDRD). This LDRD program is common in many US Labs and a substantial source of internal funding for many programs where new and exploratory efforts are being initiated. This LDRD program also allows for the lab to create an initiative on programs that they think might be of importance in the future. So it allows the lab to position itself as having already established an expertise in a certain area by the time the need for work in that field arises.

So while this lecture is given at Berkeley lab and to scientists at Berkeley lab, it applies to practically all scientists at US National Labs. If you're just starting out and working at one of these labs, this might be a useful video. If you're not, you get to hear the directions that Berkeley lab is looking into at least during the next few years.


Friday, August 05, 2011

100 Years Of Rutherford's Atom

I frequently highlight events that are happening here in the US, especially around where I live. But here's something happening across the pond (from me). The folks in Manchester, England, will have the opportunity to mark the 100th anniversary of the Rutherford's model of the atom with a series of public lectures.

The lectures will explain how fundamental physics has moved on from Rutherford's discovery to the huge and elaborate experiments taking place in the Large Hadron Collider (LHC); how medical physics is underpinned by our improved understanding of the atom; and, finally, how power is generated by the splitting of the atom, and nuclear power's safety record.

The public lectures accompany the Institute of Physics' (IOP) academic conference, 'The Rutherford Centennial Conference on Nuclear Physics' , as it was 100 years ago, in 1911, as chair of physics at the University of Manchester that Ernest Rutherford - now deemed the father of nuclear physics - devised the now familiar model of the atom.
One would hope that the series of lectures will not only give a historical view of the usefulness of the Rutherford's model, but also show clearly how we've gone past that. Anyone dealing with incoming school kids, or talking to the public, would have encountered the need to correct the impression that an atom has these electrons orbiting a nucleus, much like the planetary model of Rutherford's. As useful as that was, it is no longer accurate.


Thursday, August 04, 2011

Don't Try This At Home

I some time wonder how silly (dumb?) people can get.

A man in Sweden was arrested after he contacted authority to see if his "atom splitter" is safe to run.

The 31-year-old Handl said he had tried for months to set up a nuclear reactor at home and kept a blog about his experiments, describing how he created a small meltdown on his stove.

Only later did he realize it might not be legal and sent a question to Sweden's Radiation Authority, which answered by sending the police.
This is where a little knowledge can be dangerous, or even harmful, physically. It is what happens when crackpots crossed the line between doing things in their heads and actually doing something.


Wednesday, August 03, 2011

Debt Agreement and US Research

Now that the debt agreement has been reached by the politicians in Washington, what is the fate of US research funding?

Science Insider has a first look at what was agreed upon, and finds that things could be A LOT worse for science funding in the US based simply on what has been agreed upon for discretionary spending.

The legislation President Barack Obama signed today to avert a government default offers few details on how the United States will achieve a now-mandated $917-billion cut to discretionary spending over the next decade. And while research funding is by no means exempt, there may yet be a silver lining for U.S. scientists in the Budget Control Act of 2011.
 I think everyone who depends on federal funding for various science projects is already resigned to the fact that for the next 2 or 3 years, at least, funding will be extremely tight. It's a matter of hanging on without losing our grip while riding through this long, arduous storm.

Speaking of debt agreement, there is an interesting essay about the imaginary world of debt ceiling, and the real, physical ceiling imposed by Mother Nature. Perhaps no politicians will read it, or understand it, but you should.


Tuesday, August 02, 2011

The Physics of Guinness Beer

Physics and beer... I know to some people (you know who you are, college kids!), that's a definition of heaven. :)

This article, video, and paper should be up a lot of people's alley. It discusses the physics of Guinness beer, and tries to tackle some very profound questions:

For example, look closely at a pint of Guinness and tell me: do the bubbles go up, or do the bubbles go down? Why is the head coloured the way it is? Is beer foam a gas, liquid or solid? I thought you might enjoy this little video as a follow up, where an Irish physicist discusses the "fizzics" of bubble formation in Guinness beer.
 There is a video link to the article, which I will also link to here:

And the paper[1] that was published in Physics of Fluids (I kid you not) can be obtained from here as well.


[1] M. Robinson et al., Phys. Fluids v. 20, p.067101 (2008).

Can Insurgent Attacks Be Modelled By A Simple Equation?

University of Miami physicist Neil Johnson and his co-authors seem to think so. They have published an analysis of insurgent attacks in Iraq and Afghanistan, and discovered a pattern to such activities.

Johnson and his research team gathered publicly available data on military fatalities in Afghanistan and Iraq. On a graph, the numbers created a distinct, upward curve.

He says it wasn't just a coincidence; those numbers follow a specific mathematical pattern. In this case, the pattern translates into an equation you can punch into a handheld calculator, says Johnson.
I'm typically skeptical of this type of modeling of human behavior. In this instant, the unpredictability of even the action of one person is enough to screw up the predictions, and that in turn could have a chain of consequences.

Besides, once something like this is published, who is to say that these insurgents would not become aware of their pattern, and try to plan their attacks to NOT follow such pattern?


Monday, August 01, 2011

Hawking Tackles "Curiosity"

The Discovery Channel's "Curiosity" series kick-off episode on Aug. 7 will feature Stephen Hawking's provocative look at the need (or lack of the need) for a creator in the formation of our universe.

"I recently published a book that asked if God created the universe. It caused something of a stir," Hawking, 69, begins on the episode. (The "stir", in fact, was religious leaders denouncing his book's conclusion that God was unnecessary to the universe.) On the show, he takes viewers on a walk through humanity's history of appraising our place in the universe, from Vikings facing down eclipses to the laws of modern cosmology, which explain the origin and structure of universe. "I believe the discovery of these laws is mankind's greatest achievement," he says.
 Of course, this is based on his "Grand Design" book that received quite a bit of publicity. It will be interesting to see how he will sell this idea on TV. Will he offend even more people? We can only hope so! :)