Monday, May 30, 2011

Goodnight, Goodbye, And Thank You, Spirit

NASA has terminated all attempts at contacting the Spirit Rover on Mars after the latest unsuccessful attempts.

This is not like calling off the search for a missing human explorer. And yet it feels similar, even though Spirit is a six-wheeled robotic vehicle, not even remotely human in appearance, even by Wall-E standards. Still, it is strangely easy to personify Spirit. Over the years, it has seemed intrepid, valiant, determined. It has no consciousness, but there has been something self-knowing in the photographs it has taken of itself, with Mars in the background. In its plight — stuck on the edge of a small crater tens of millions of miles from Earth — we feel a celestial solitude, as if we were marooned there ourselves.

Check out the Spirit coming strip on the PhysicsWorld blog.

It was a rover that could, and performed way beyond all expectations. It is a testament to the ingenuity of those who designed, built, and operated it.


Sunday, May 29, 2011

Bill Foster To Run For Congress Again

Physicist and former US Congressman Bill Foster is mounting a campaign to win a congressional seat at the next election.

Foster represented the 14th Congressional District for nearly three years after winning a high-profile special election in March 2008 to take the seat that had been held by Republican Dennis Hastert, the longtime House speaker who retired several months after Democrats took over the House.
But Foster’s time in Congress came to an end after last November’s Republican tidal wave, when Randy Hultgren, a state senator from Winfield whose supporters included tea party activists, reclaimed the seat for the GOP.

The number of physicists in the US House of Representatives dropped quite a bit this time with Foster's loss and the retirement of Vern Ehlers. Last count, I think Rush Holt might be the only one left! And he's the only one who could beat Watson!


Friday, May 27, 2011

Slow Recovery of Japanese Physics Facilities

I just found this report on the current recovery progress in Japan after the recent earthquake/tsunami. It looks like in some facilities, significant work still has to be done. This is discounting the infrastructure issues of the surrounding areas that provides water, electricity, and access/roadways.

The recovery will be very slow. I know of many colleagues who thought they would be busy with work and/or travel to Japan this summer who suddenly find themselves having a wide-open few months due to conference and work cancellations.


Thursday, May 26, 2011

Freezing Liquid Nitrogen

Those fun people at JLab are at it again. This time, they freeze liquid nitrogen using evaporative cooling.


No Electric Dipole Moment For Electron Yet

The most accurate experiment to detect any electric dipole moment for an electron has detected none[1]. Don't miss also the News and Views article of this work in the same issue of Nature.

This experiment has received quite a bit of media coverage (see here, here, here, and here).


[1] J.J. Hudson et al., Nature v.473, p.493 (2011).

Wednesday, May 25, 2011

Where Do Tears In Zero-G Go?

Nowhere! They just stay in front of your eyes!

That's what happened to astronaut Andrew Feustel during a space walk when his eyes got stung by something and started to water.

NASA's lead spacewalk officer in Mission Control, Allison Bolinger, later identified the irritant as an anti-fogging solution that had been applied to the inside of Feustel's helmet. It's essentially off-the-shelf dishwashing soap and occasionally flakes off, if not buffed properly, and can get in a spacewalker's eye.

Feustel managed to rub his eye against a foam block in his helmet — normally used for clearing ears — and said that helped. The spacewalkers noted that tears in space "don't fall off of your eye ... they kind of stay there."

Yup! Another property of gravity that we take for granted.


The Physics of Drinking Dogs

We have now firm confirmation that dogs and cats drink alike!

Earlier on, there was a study on the mechanics of cats drinking water. It turns out that in a new study of dogs drinking water using high speed camera and x-ray images, dogs drink the same way as well!

This footage shows that as the tongue touches the surface of the water, the liquid adheres to it, creating a water column as the tongue is drawn back towards the mouth. The dog then snaps its mouth closed just as the water begins to fall backwards towards the bowl.

The research, published in the journal Biology Letters, has surprised scientists because it reveals that cats and dogs drink in the same way.

I'll post the exact citation to the paper when I find it.


Tuesday, May 24, 2011

Argonne on "Jeopardy" Again

Seems like the lab is quite popular whenever there is a category on cars. It was on Jeopardy earlier this year, and it is on Jeopardy again this past week.


The Physics (Or Lack Thereof) Of Souls

I've tackled the subject of "afterlife" and "life after death" before on here. But Sean Carroll took it a step further and really examined it with respect to what we know of today in terms of the physics. He even brought out the Dirac equation.

If you believe in an immaterial soul that interacts with our bodies, you need to believe that this equation is not right, even at everyday energies. There needs to be a new term (at minimum) on the right, representing how the soul interacts with electrons. (If that term doesn't exist, electrons will just go on their way as if there weren't any soul at all, and then what's the point?) So any respectable scientist who took this idea seriously would be asking -- what form does that interaction take? Is it local in spacetime? Does the soul respect gauge invariance and Lorentz invariance? Does the soul have a Hamiltonian? Do the interactions preserve unitarity and conservation of information?

What it means is this. If one wants to argue that our current understanding actually SUPPORTS the existence of souls and afterlife, then one MUST reformulate this equation and show exactly the physics and dynamics of such entities the way we understand all other parts of physics. Now this is very important because to CLAIM that current science are consistent with such phenomenon, or even explained it, one must provide such formalism, or else, it is just a handwaving speculation. The latter is something that Deepak Chopra has been doing, which is piggy-backing onto modern physics without providing any valid formalism for it.

But if one claims that souls and afterlife are BEYOND current-day physics, then one has to throw out everything that we know (and know to be valid since we are USING them in our everyday lives) and come up with something new. This will present a very daunting task.

We don't choose theories in a vacuum. We are allowed -- indeed, required -- to ask how claims about how the world works fit in with other things we know about how the world works. I've been talking here like a particle physicist, but there's an analogous line of reasoning that would come from evolutionary biology. Presumably amino acids and proteins don't have souls that persist after death. What about viruses or bacteria? Where upon the chain of evolution from our monocellular ancestors to today did organisms stop being described purely as atoms interacting through gravity and electromagnetism, and develop an immaterial immortal soul?

We simply can't manipulate or change one part of physics, without affecting other parts. If one proposes a new physics, then it is a valid to look at consequences of that physics and see how it affects other parts. And this is where many new theories will have problems because it has to not only predict new things, but also be consistent with others that we have verified. That's why I said it is a daunting task.


Monday, May 23, 2011

Brookhaven Lab Wins PR Award

In another example of a scientific organization really putting in thoughtful effort to convey news and messages to the media and public, Brookhaven National Laboratory has won two "Bulldog" awards for excellence in media and public relations.

The Brookhaven Lab campaign won a Gold award in the “Best Campaign Under $25,000” category, and a Bronze award in the “Best Not-for-Profit/Association/Government Campaign” category. In 2010, the campaign also won a Bronze Anvil Award of Commendation from the Public Relations Society of America.
In the award-winning campaign, Brookhaven Lab and its communications counsel developed and executed a strategy to announce two major results related to RHIC scientists’ quest for the primordial matter known as quark-gluon plasma (QGP) through RHIC’s high-speed collisions of heavy ions. Scientists believe such a quark-gluon plasma filled the early universe some 14 billion years ago, before ordinary constituents of matter such as protons and neutrons — let alone stars, planets, and galaxies — ever formed.

Well done!


Saturday, May 21, 2011

The Physics of Blue Jeans

Here's something to show that there's physics in everything. This article covers the physics of blue jeans - everything you wanted to know about the physics aspects of blue jeans but were afraid to ask!


The Physics of Sailing for Pirates

Now, we're not talking about the nasty pirates off the coast of Somalia that have been hijacking ships. We are talking about the romanticized version of pirates here, and since this weekend is the opening weekend of Disney's "Pirates of the Caribbean - On Stranger Tides", this is a good time to talk one aspect of the physics of sailing.

The fastest way to sail is at a forty-five degree angle to incoming wind. I know! Ye minds have been blown! But it works. the best way to understand is to think of the wing of an airplane. It has a flat side an a rounded side. The rounded side is tough for air to get around - it has to move quicker, and there's less of it making the dash - so the air pressure is lower on that side of the wing. The flat side is easy for air to move by, and so the air pressure is higher. That pushes the plane upwards. When wind hits the sail, it puffs out, making one side rounded like an airplane's upper wing, and the other side a hollow. The air pressure in the hollow is high and in on the puff is low. The keel keeps the boat from drifting sideways, and so it moves the only way it can - forward.

So the expression "may the wind be at your back" may not be such a good thing in sailing.


Friday, May 20, 2011

Introducing Synchrotrons Into the Classroom

A neat video that describes a program at Brookhaven Lab that allows high school teachers, and their students, the opportunity to make a proposal for an experiment.

I wish they revealed the results of the experiment! That's the only part missing in here.


AMS Attached To Space Station

Finally, after such a long wait, the ISS is now actually a useful scientific laboratory! The AMS has been successfully installed to the International Space Station.

The task was done over several hours in the middle of the night as astronauts used robotic arms from both the shuttle and the space station to lift the AMS out of the shuttle’s cargo bay then maneuver it into place and install it on the station. They were finished by 5:46 a.m. Eastern time.

The report also stated that it has already been "turned on", whatever that means. I'm sure there's a lot of diagnostic checks and calibration being done before actual data-taking.

Check out the AMS on-orbit images at the AMS homepage.


Thursday, May 19, 2011

Probing Potential PhDs

Oh, if you missed this article when it appeared last week, don't miss it now! It's a fun article to read about an interview process conducted in China to find potential PhD candidates for SUNY-Stony Brook University. Many of us even with PhDs can learn a thing or two of the conceptual questions that were asked.

I like Crease's expression for making sure that what you are conveying is at the same level that the intended audience can understand:

The challenge questions that one looks for are those that do not involve calculation but conceptualization, or a general sense of the physics involved. The student must then convey the conceptualization and how it settles the problem swiftly and succinctly at the undergraduate level. These questions therefore test what I like to call "impedance matching", or the ability to match the "load" of one's explanation to the environment in which it must be understood.

I like that expression: impedance matching. I think I'll copy it! :)


Back From Vacation

Just got back from a week-long vacation. It'll take me a few days to catch up with what's been going on. At least the AMS lifted off with the space shuttle and will be installed today. After such a long wait, it is now finally up where it belongs. Hopefully, it won't be too long before we start to get data from it.


Wednesday, May 11, 2011

A Brief Introduction to Band Structure in Three Dimensions

This is a very handy and quick tutorial on the calculation of band structure in solids. It's useful to see how QM principles is applied to our understanding of solids such as semiconductors, etc. which leads to our ability to know how to make our modern electronics.

Abstract: Without our ability to model and manipulate the band structure of semiconducting materials, the modern digital computer would be impractically large, hot, and expensive. In the undergraduate QM curriculum, we studied the effect of spatially periodic potentials on the spectrum of a charged particle in one dimension. We would like to understand how to extend these methods to model actual crystalline materials. Along the way, we will explore the construction of periodic potentials in three dimensions, and we use this framework to relate the single-particle Hamiltonian to the potential contribution from each atom. We then construct a crude model system analogous to the semiconductor silicon, and demonstrate the appearance of level splitting and band gaps as the strength of the potential is varied, in accordance with our intuition from the one-dimensional case. We discuss refinements of the model to include many-particle effects, and finally we show how a careful choice of the potential function leads to good agreement with the correct band diagram for silicon.


Tuesday, May 10, 2011

The Road To Discovery Of Atom's Nucleus

This is an interesting and brief historical account Ernest Rutherford's discovery of the nucleus.

The one interesting part that I read is how shrewd he was.

With blossoming international scientific fame, Rutherford was regularly offered posts in America and elsewhere. He accepted none because McGill had superb laboratories and support for research, but he was wise enough to let the McGill authorities know of each approach; they increased his salary each time. However, Rutherford also wished to be nearer the centre of science, which was England, where he would have access to excellent research students and closer contact with notable scientists. His desire was noted. Arthur Schuster, being from a wealthy family, said he would step down from his chair at Manchester University provided that it was offered to Rutherford, and in 1907 Rutherford moved to Manchester.

As always, in reading historical account such as this, it continues to amaze me how many "household names" are involved, either directly or indirectly. We see the involvement of Geiger, Marsden, Bohr, etc...


Willard Boyle: 1924–2011

We note today the passing of a Physics Nobel Laureate, and someone whose discovery/invention is certainly influential in our lives. Willard Boyle, a co-inventor of the CCD, passed away at the age of 86.

Like many Nobel laureates, the prize came late in Boyle's life, when he was 85. As his long-time friend and Nova Scotia local councillor Ron MacNutt told the Canadian Broadcasting Corporation yesterday, Boyle "had some regret that that recognition came a little bit late for him to get out and do more of that, to talk to younger children in school". An earlier award, MacNutt added, might have let Boyle influence even more people in his life.

Still, I'm glad that the Nobel committee gave him his award and that he gets the recognition, even late in life. BTW, here's another example you can give to people who thinks that physics and physicists only deals with esoteric, no-application knowledge.


Monday, May 09, 2011

Particle Physics Fights Cancer

Jennifer Ouellette has a wonderful article on a new method to fight cancer, using knowledge that we gained from high energy/particle physics. In this case, one is using an imaging technique from a Cerenkov radiation.

This is just one more example of the benefits one obtain (and taken for granted) from so-called esoteric fields such as elementary particle/high energy physics. I've mentioned earlier about such benefits that many people are not aware of. This is in addition to the fact that basic knowledge is so valuable, even when we initially do not realize its potential benefits and application later on. And let's not forget that out of all of this is the advancement in accelerator physics that continues to produce numerous crucial benefits.


Saturday, May 07, 2011

Scotland's Bid To Honor Its Only Nobel Prize Winner In Physics

As customary of my effort in highlighting the legacy of physicists who we all should know but get very little mention, especially in the popular media, here is a news report of Scotland's effort to honor its only Physics Nobel Prize winner - Charles Thomson Rees Wilson - who was given the Nobel prize for the invention of the cloud chamber.

Now a group of prominent scientists and politicians who believe his achievements rank alongside those of Albert Einstein and Marie Curie are to launch a campaign to have issued a commemorative banknote to honour long-forgotten inventor CTR Wilson. Wilson was awarded the world's most prestigious science prize in 1927 for his invention of the cloud chamber, inspired by the optical effects he saw in the sky in the Highlands. His invention was pivotal in the development of particle physics and has been described as "the most original and wonderful instrument in scientific history".

The cloud chamber, of course, was one of the earliest particle detector that was used, and featured prominently in the early high energy physics experiments. I still use a cloud chamber whenever we have visitors, and it is amazing how many have never see such a thing. People continually are amazed when they see all of these tracks zipping around in the chamber. It reinforced the idea that we are surrounded by cosmic/terrestrial "radiation", and something this visual tends to stick in people's head faster and easier than simply telling them, or showing them on posters.


Friday, May 06, 2011

Gravity Probe B Confirms Einstein's General Relativity

There are many news article on the latest report from Gravity Probe B stating how the results are consistent with predictions from Einstein's General Relativity (see here, here, and here). But the one I will highlight here is from Jennifer Ouellette who started out her article with ...

It's a sad day for physics crackpots bent on disproving relativity, because once again, it turns out that Einstein was right.

I love it!

Obviously, she had encountered, as I have, all of these sad creatures who continue to want to bash Einstein's Special and General Relativity.


What Students Learn When Studying Physics Practice Exam Problems

A rather interesting study on a topic that I don't think have been looked at much. This group of researchers try to evaluate what students understand and gain when they were given past, old exams (some with solutions) to practice and study on[1].

Abstract: We developed a web-based tool to provide students with access to old exam problems and solutions. By controlling the order in which students saw the problems, as well as their access to solutions, we obtained data about student learning by studying old exam problems. Our data suggest that in general students learn from doing old exam problems, and that having access to the problem solutions increases their learning. However, the data also suggest the depth of learning may be relatively shallow. In addition, the data show that doing old exam problems provides important formative assessment about the student’s overall preparedness for the exam and their particular areas of strength and weakness.

In particular, they were trying to address these questions:

How much do students learn from doing a multiple-choice exam problem and getting feedback about the correct answer? Does providing students with a complete solution improve their learning? How accurately does student performance on practice exam problems predict their performance on actual exam problems? In particular, can it help predict areas that a student should spend more time studying?

Going over the paper, I first had a chuckle when looking at Fig. 1 which shows that most of the students tried the practice exams within 24 hours of the exam! Typical last-minute cramming! :)

It appears that these are "multiple choice" tests. Although the authors don't think that this may make a significant difference, I'm not so sure about that, because one also can't discount random selection, or at least, a student making an educated guess without actually knowing the correct answer.

Still, it's an interesting study to read.


[1] W. Fakcharoenphol et al., Phys. Rev. ST Phys. Educ. Res. v.7, p.010107 (2011).

Thursday, May 05, 2011

Bosons In High Temperature Superconductors: An Experimental Survey

This is a wonderful review article on the issue of the bosonic mode that couples to the quasiparticle in the cuprate superconductors[1]. Deciphering the nature of this boson is THE key issue in the mechanism of superconductivity for this family of material. This article compiles the relevant experimental data from angle-resolved photoemission spectroscopy (ARPES), optical measurement, and tunneling spectroscopy, to present the state of knowledge about this bosonic mode.

What makes this article even more useful is that, if you're not familiar with the physics surrounding these techniques, especially for ARPES and optical conductivity, it provides a nice brief summary of these techniques and what they actually measure that can provide the information needed.

A highly useful article, in more ways than one.



309 Antihydrogen Trapped for 1000 Seconds

This made the news at least a week ago, but only now has the story appeared on PhysicsWorld, so here it is.

The ALPHA team produced the antihydrogen by merging two clouds of cold plasmas: one containing positrons and the other antiprotons. By improving their trapping techniques, the researchers managed to hold the antihydrogen for more than 1000 s. These advances also meant that five times as many atoms were trapped per attempt. Calculations based on data from the experiment suggest that after about 0.5 s, most of the trapped antihydrogen atoms reach their lowest energy or ground state. As a result, the team says that its trapped sample is the first antihydrogen obtained in the ground state.

As in this group's earlier attempt, this is such an amazing accomplishment. The fact that they can hold these that long opens up a whole slew of tests that one can conducts on very fundamental aspects of physics. So this isn't just an astounding accomplishment, but also a tool to investigate other things. That is why this is so important.


Wednesday, May 04, 2011

New Light On Dark Energy

If you have 2 hours (yowzah!) to spare, here's a video of a panel discussion on the latest development in our understanding of Dark Energy.


Publishing A Turd Is Still A Turd

OK, I've made wholesale judgement of something that I haven't read, and something I don't have a very good knowledge of. In other words, I'm doing exactly what I've criticized crackpots for doing. I fully admit it, and I'm fully owning it! So there!

But really, as I've mentioned earlier, you can only counter crackpottery with another crackpottery. And I'm going to judge this with the same level of superficial knowledge as this person is doing by invoking his superficial level of knowledge of quantum mechanics. I think that is a fair deal, no?

This article out of Cornell highlights a series of publication on ESP and other paranormal phenomena. Oh yes, that again! Supposedly, this series of publication is based on new research that somehow shows "convincing" evidence for it. But just in reading this article, are you truly convinced?

In one experiment, Bem asked students to pick one of two curtains as the one they thought contained a picture behind it. Although the students correctly chose the correct curtain 53.1 percent of the time, which appears to not be too different from the expected 50 percent, Bem believes this value is, in fact, statistically significant and unlikely to appear by chance.

A paper published by researchers at the University of Amsterdam suggests that Bem uses incorrect statistical methodology by using one-tailed tests instead of two-tailed tests, which would be more difficult to prove significance for. By re-analyzing Bem’s data using a different set of statistical analysis tools, however, the researchs show that Bem’s data is not statistically significant. Bem believes this claim is “an absolutely ridiculous argument to be making” and that the assumptions used by the University of Amsterdam researchers are “unrealistic.”

Er... yeah! Of course!

But it gets better when physics is invoked.

It is Bem’s belief that there is “nothing in physics that is contradicted” because although ESP might not be in line with Newtonian physics, it is in line with quantum physics.

He added, “The fact that we do not have a mechanism to explain it is a major deterrent. But almost every theory first started out as an unexplainable phenomenon.”

Er... what is it with "quantum physics" that is consistent with this cra... er ... study? Let me guess. He's invoking quantum entanglement? Superposition? The Cat? If he is, he is barking up the wrong tree, very much like Deepak Chopra. And thus, my point about superficial understanding of something. But what is funny is the gall he had to say that " ... almost every theory first started out as an unexplainable phenomenon.. " Since when is this something new to be "first started out"? Claims of ESP and such have been made for decades, even longer! In all of those years, they still can't get out of first base, out of the "discovery" mode. Other legitimate phenomena have gone beyond the discovery/confirmation phase and now have proper theoretical descriptions.

This thing cannot get beyond the fact that they can't differentiate their signal from random noise. The statistical analysis of such a thing is suspect. It is why the effect is not convincing.


Tuesday, May 03, 2011

Michael Tinkham

OK, I completely missed the passing of Michael Tinkham last year. I only heard of the news when I read his obituary in latest edition of Physics Today.

I did not have the privilege to have known him, or to have met him, unlike his students, postdocs, and colleagues. However, he certainly made a huge impact on me professionally. His "Introduction to Superconductivity" book was my "bible" when I was in graduate school. In fact, his derivation of the BCS Theory was the one I studied from very closely, above all others. I would not have grasped the theory of superconductivity as well and as fast as I did if it weren't for this book.

So thank you, Michael Tinkham. I think your legacy, through your work and your books, will live on.


2011 APS Apil Meeting Presentations Available Online

Viewgraphs of selected talks from the 2011 APS April Meeting are available online. This could be useful to those who can't make it to the April Meeting, so this is definitely a good idea. It appears that this is still in a trial basis, but I hope it continues.

Now, they need to do the same for the March Meeting.