Traffic Jams Happen, Get Used to It

I've heard about this research study, but I didn't pay that much attention to it until I saw that they had a video of this effect that was rather neat. It also confirms what I had suspected for a while.

The study was done by a group of Japanese scientists/mathematicians about traffic jams that happened without any bottleneck[1]. In other words, there's no obvious obstacles, such as an on-ramp, or a constrictions, etc. that would be obvious causes for a traffic jam. All they did was increase the traffic density, and at some point, there's some "critical density" in which traffic jams simply occurs because people just don't all drive at the same speed.

What is need is that you can actually this taking place in the video that they have included. I've always suspected this. I drive roughly 31 miles each way to work every day. I sometime get stuck in a couple of slow spots where traffic either slows down or stopped for periods of time. Yet, as you you drive some more, you speed back up again as if nothing has happened, and you don't see any reason why the traffic slowed down. I tend to blame it on slow cars in the left lane, but I had no proof that was the usual cause. Now, I have some evidence to back my haunch! :)

Zz.

[1] Y. Sugiyama et al., New Journal of Physics v.10 p.033001 (2008).

Time-Keeping Milestone

There are a couple of interesting reports in the latest issue of Science this week (Science 28 March 2008). Two papers have made the most accurate measurement of time-keeping to date. One uses the optical transition from ions[1], while the other uses neutral atoms[2]. They produced a time accuracy of up to 10^-17 and 10^-16 second, respectively, which is significantly more accurate than the Cs atomic clock.

However, as pointed out in the Perspective by Daniel Kleppner in the same issue, with an error budget that includes perturbation of the order of 10^-18 s, such precision now has to consider the effects of General Relativity.

When precision is pushed to new levels, ever more subtle effects must be taken into account. For instance, the error budget includes a small contribution, 1 mult 10-18, due to an uncertainty in the gravitational potential of the two clocks. This corresponds to a difference in their altitudes of 1 cm. This heralds one of the most interesting aspects of time keeping with optical clocks: The effects of general relativity that mix time with gravity are starting to approach a point that will require rethinking the basic concept of "keeping time."

The "two clocks" referred here are the two ion clocks used in the T. Rosenband et al. experiments - Al+ ion and Hg+ ion clocks. Having clocks that are now sensitive enough to detect effects of GR would certainly open up a whole possibility of testing GR even more.

Zz.

[1] T. Rosenband et al., Science v.319, p.1808 (2008).
[2] A. D. Ludlow et al., Science v.319, p.1805 (2008).

Gyroball - A "Nothing Ball"?

The controversy surrounding the existence of a "gyroball" in the sports of baseball continues. Recall that I reported on this a while ago of the skepticism that such a ball can be thrown. Now there's a new follow up to this issue where even more people are simply questioning why this is such a big deal.

Adair said it actually mimics a pitch in cricket that "probably goes back 100 years," its odd-duck spin more useful in that sport because the ball is bounced to the batsman. "It had various names," Adair said. "The 'googly' and the 'Chinaman,' because a British bowler of Chinese extraction threw it.'

"Properly thrown through the air, the gyroball does nothing. It's a 'nothing ball!'"

Or as University of Illinois physics professor Alan Nathan amended, "A 'qualified nothing ball.' Because if the batter is expecting a 'something ball' [with a break or a dip], that makes a 'nothing ball' effective."

Sort of a reverse psychology? :)

I wish they just play ball!

Zz.

Lawsuit: Huge Atom Smasher Could Destroy World

This news has been making the rounds around various blogs and news wires. A couple of wackos have decided to file a lawsuit against the US Dept. of Energy (DOE) and CERN to stop them from building the Large Hadron Collider (LHC) at CERN.

I debated on whether I want to dignify this stupidity by reporting it on here. But then again, it is going to be reported anyway. This news report has some brief description of the background of the yoohoos that filed the lawsuit.

Not included among the documents is Wagner's own indictment last month on identity-theft charges tied to an ongoing legal battle over a botanical garden on the Big Island of Hawaii, but you can read about that here.

Most physicists say Wagner's worries are unfounded. Micro black holes would evaporate nearly instantly instead of combining to form larger ones, they say, and the "strangelet" particles he frets would freeze the world would in fact fall apart quickly.

Wagner's own background is a bit fuzzy. He claims to have minored in physics at U.C. Berkeley, gone to law school, taught elementary-school science and worked in nuclear medicine at health facilities — but he doesn't appear to have an advanced degree in science.

Sancho's qualifications are even murkier, but the lawsuit identifies him as a Spanish citizen residing in the U.S., even if his presence makes the entire case a bit, um, quixotic.

And before someone accuse me of simply trying to attack the credibility of the wackos rather than address the "physics", let me point one very glaring and important observation here. There are already extremely energetic particles colliding with other particles in our universe. For example, the recent Auger Observatory results studied the origin of the these cosmic particles, that have energies in the 100's of TeV, something that CERN cannot even come close to. These particles have been around for million (even billions) of years, and have made gazillions of collisions. If such high energy collisions can create blackholes, we would have been swallowed and destroy by them already by now. Hello? Is this not obvious?

It looks like the crackpots are now getting a bit more daring. But now, rather than just being an internet nuisance, they are now being a pain-in-the-rear-end with their frivolous lawsuits. So anyone who thinks that these crackpots are just a "harmless" bunch of losers, think again. They're still losers, but they're definitely not always harmless.

Zz.

Giant Magnetoresistance

The 2007 Nobel Prize in Physics was awarded to Albert Fert and Peter Grünberg for the discovery of the Giant Magnetoresistance, as reported earlier. I had also given a good link that explains what GMR is. Still, one can never have too many good explanations of what it is, so here's another one, this time, it's an article from Physics Central.

This is actually quite appropriate because it is another example on how basic research in strongly-correlated electron systems can produce something that becomes important in our daily lives. It is why basic research is important. One would hope that this message gets across to those people making funding decisions.

Zz.

Webcast: Nobel Laureate to lecture on "Blind Chance or Intelligent Design: The Need for Basic Research," April 8, 2008

Here is the announcement for the next series of Honeywell-Nobel Initiative lecture series:

Some scientific advances, such as the discoveries of X-rays and penicillin were stumbled upon through serendipity. Others, like streptomycin and nuclear reactors, resulted from targeted and specific research. Honeywell will be presenting a lecture and Webcast by Nobel Laureate Dr. Sheldon Glashow on “Blind Chance or Intelligent Design: The Need for Basic Research" at 9:00AM on April 9, 2008 in Beijing (9:00PM pm April 8, 2008 in Eastern Time).

Dr. Glashow’s many research accomplishments in theoretical physics include his prediction of the charmed quark (for which he was awarded the Oppenheimer Medal) and his seminal contributions to the unified theory of weak and electromagnetic interactions (for which he shared the 1979 Nobel Prize in Physics).

For the past quarter century, while he has continued his fundamental researches in particle physics and cosmology, Dr. Glashow has also focused on stimulating interest in science among high-school students and encouraging scientific literacy among non-science students at the university level.

Dr. Glashow will be delivering a lecture to students at Beihang University, Beijing, China on April 9. A live Webcast of his remarks, as well as related content, will be available for viewing from Honeywell Science.

The video of the recent lecture on Cosmic Background Radiation by George Smoot is now available online.



Zz.

Under Control: Keeping the LHC Beams on Track

While people do have some idea of the size and the complexity of the LHC, most do not have a good 'scale' of the issues involved here. There are some astounding issues and problems that they have to deal with. Keeping the LHC beam under control, and what to do when it veers off course is a major issue.

This article tries to impart some idea on the control and contingency issues of the LHC beam. For example:

The complexity means that repairs of any damaged equipment will take a long time. For example, it will take about 30 days to change a superconducting magnet. Then there is the question of damage if systems go wrong. The energy stored in the beams and magnets is more than twice the levels of other machines. That accumulated in the beam could, for example, melt 500 kg of copper. All of this means that the LHC machine must be protected at all costs. If an incident occurs during operation, it is critical that it is possible to determine what has happened and trace the cause. Moreover, operation should not resume if the machine is not back in a good working state.

So this is not case where you can just simply pull the switch if something goes wrong. They have to make sure they dump the beam properly without causing damage to all the components along the ring.

This is, of course, a common issue at large particle accelerator facilities, including the Tevatron. I am still at awed at some of the things they are able to do, and at the scale that they are doing in. I some time wish the most of the general public has some clue on the level of complexity and the accomplishments at just being able to run such an experiment.

Zz.

Accelerator in a Bowl

This is a cool demonstration to illustrate how they accelerate particles at the Tevatron at Fermilab.



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Ettore Majorana And His Heritage Seventy Years Later

For those who are not familiar with the story of Ettore Majorana, this is probably a good introduction to his life, and his contribution to physics within such a short period of time till he mysteriously disappeared some 70 years ago. I consider him the Emelia Earhart or the Jimmy Hoffa of physics because of this disappearance, which still has not been solved.

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An Inquiry Into the Reproduction of Physics-Phobic Children by Physics-Phobic Teachers

I know! I was intrigued by the title as well! :)

First of all, this is a paper that was originally published in Japanese, and this English version is, what appears to be, an almost direct translation. So there will be some awkward passages here and there. If you keep that in mind, everything should be OK (just think of literal translation and you'll be fine).

The authors studied the effect of teachers who themselves have little understanding or interest in physics on students. Somehow, the teachers disinterest in physics can (surprise!) transfers itself to the students.

It is interesting to note that, with the budget crisis in physics in the US and UK, we tout the high investments in science in Europe and Asia, particularly Japan, China, and Korea. But it is obvious from this report that even in Japan, they also face, to a lesser degree, problems in getting students to do physics, not just as a career, but in terms of being educated or literate in it.

Zz.

Considering Science Education

There has been only one essay so far in which I flat out tell everyone to go read it. It was the Helen Quinn essay "Belief and Knowledge - A Plea About Language".

OK, so here comes another one. In the March 21, 2008 issue of Science, an editorial by Bruce Alberts is a MUST READ by everyone and anyone (Science, v.319. p.1589 (2008)). He argues why science education is important to everyone, and not just science students.

I consider science education to be critically important to both science and the world, and I shall frequently address this topic on this page. Let's start with a big-picture view. The scientific enterprise has greatly advanced our understanding of the natural world and has thereby enabled the creation of countless medicines and useful devices. It has also led to behaviors that have improved lives. The public appreciates these practical benefits of science, and science and scientists are generally respected, even by those who are not familiar with how science works or what exactly it has discovered.

But society may less appreciate the advantage of having everyone aquire, as part of their formal education, the ways of thinking and behaving that are central to the practice of successful science: scientific habits of mind. These habits include a skeptical attitude toward dogmatic claims and a strong desire for logic and evidence. As famed astronomer Carl Sagan put it, science is our best "bunk" detector. Individuals and societies clearly need a means to logically test the onslaught of constant clever attempts to manipulate our purchasing and political decisions. They also need to challenge what is irrational, including the intolerance that fuels so many regional and global conflicts.

I totally agree. If you have read the beginning of my series on revamping the intro physics labs, I've always argued that these labs can be a valuable tool to these students (the majority of whom are not physics majors) as an illustration on how we accept something to be valid, or how we arrive at some of our knowledge. We should emphasize the idea that using scientific technique to verify something is the strongest degree of certainty that one can have in any endeavor. It is why scientific evidence is different than anecdotal evidence. It is why astrology is not a science, whereas astronomy is. The fact that many still can't tell the difference is an important reflection on how these arrive at what they perceive to be true. This means that many of the decisions they make may not be based on valid information or evidence.

So think of what happens when they vote for their political leaders....

Zz.

The Squeeze at Argonne And Fermilab

.. and this "squeeze" comes both in terms of funding and science.

Three months into the disastrous Omnibus bill, this article looks at the impact on the two national laboratories in the Chicago area - Fermi National Accelerator and Argonne National Laboratory.

To say that the mood and the morale are low is to put it mildly. One good thing about this article is that it highlights each of the facility that has been affected, and what kind of science and impact it has.

As far as I can tell, the outlook for the immediate future isn't rosy either. Even though the president's FY09 proposal calls for immediate increase in all affected areas, everyone here is almost certain that Congress is not going to pass this budget any time soon and will wait instead until after the general election. This means that we will be saddled with a continuing resolution, and will adopt the disastrous FY08 budget for the remainder of the year and into next year.

Things are not looking good for science in the US, despite all the lip service that has been given about its importance.

Zz.

The Science of Tangled Cord

Next time you have to untangled the cords from your electronics, you can at least think of it as a complicated physics process. :)

This news article describes a recent PNAS paper on this very issue.

Knot formation had been studied a lot by mathematicians, but not much by physicists. Smith was worried that the work wouldn't be taken seriously, but it ended up being published in the prestigious Proceedings of the National Academy of Sciences.

"The way that you get a knot is the string has to bend back on itself, coil back on itself," Smith said. As a string or cord tumbles, the end of it has a 50 percent chance of weaving to the left or the right of the coils, and under or over the coils, sort of like random braiding, Smith said.

The exact citation for this paper (which none of these popular newspapers ever give) is:

Dorian M. Raymer and Douglas E. Smith, PNAS v.104, p.16432 (2007).

Don't get all tied up with it.

:)

Zz.

Interpretation of Quantum Mechanics - The New Religion

First of all, a clarification and a qualification. Most physicists (at least the ones that I come in contact with throughout my years as a student and as a physicist) don't really care about the various interpretations of quantum mechanics. It really is a non-issues 99.9% of the time. So essentially, we practice Feynman's "Shut Up And Calculate" philosophy where the formalism and what empirical evidence that it can produce is what we care about.

Now, in one of my rants in "Imagination Without Knowledge is Ignorance Waiting to Happen", I mention about many crackpots who have argued that physicists simply want to keep the status quo as far as our understanding of the universe goes, that all we care about is upholding the current laws and theories. We can't, as some put it, work "outside the box". Some even compare to our "devotion" towards not wanting to drop our current understanding as a "religion".

This, of course, is stupid, and false, on many different levels, as I've mentioned in that blog entry. Still, there is one aspect of physics in which, I hate to say, is starting to look like a religion, and it has nothing to do whatsoever with what these crackpots have in mind. In fact, I don't think any of them could even comprehend these things well enough to know any better.

What I find in physics to be no different than a religion is the rabid devotion of some people, physicists included, to the various interpretation of quantum mechanics. These interpretations could range from the "popular" Copenhagen Interpretation (CI), to Many-World Interpretation (MWI), to Bohm Pilot Wave (BPW), etc.. etc. Now, again, to be fair, this issue comes up only in a very small percentage of practicing physicists. I tend to find more of these discussions on physics forums rather than in prominent physics journals. And certainly, amateurs and philosophers tend to be more fascinated by this issue than the overwhelming majority of physicists. So in physics, this "religion problem" isn't a widespread epidemic.

Still, those who are devoted to this is not doing physics any favor. I find that the rabid devotion to such various interpretation (rather than just a casual attitude about it) rather puzzling and contrary to how one accepts something to be valid in physics. This is why I find that the devotion to any such interpretation as being no different than a religion:

1. There's no empirical evidence that shows one being "better" than the other. All of them come up with the same analytical form within the formal QM. The similarities with religion is obvious here. This means that there's nothing to support which is better, and they all come up with the same answer, at best, so far.

2. Yet, the devotees in each camp tout why such-and-such is more "logical" or "rational" or "conceptually sensible", etc. Without empirical evidence to support such claim, this is nothing more than a preference based on a matter of tastes! We might as well argue for our favorite color, or, in this case, our favorite religion. This is no different than the different religions and the many followers that they have. Each one will tout the superiority of its belief system, or why it is the "truth", etc. Yet, in none of these are there any empirical evidence to separate and support these claims.

Now one could argue that isn't what is being taught in QM classes more along the lines of adopting the CI? I don't believe so, because in the end, it is the formalism that is more important, and there's no ambiguity at all there. And if it really is CI that is being instilled into these students, how come most of them grow up and adopt the "Shut Up and Calculate" point of view and not become a CI devotee?

I'm not saying that at some point, there won't be a "tie-breaker", be it a further refinement to these various interpretations that make them distinctly different from each other, and/or new tests would come out to allow for direct verification of each one. But until then, why are people "believing" in something that, at the very foundation, is simply a matter of tastes?

Zz.

Iron-Based High-Tc Superconductors

This certainly came out of nowhere.

There's another "high-Tc" superconductor joining the fun. This time, unlike the cuprates, it consist of iron-arsenic planes, and is doped with fluoride atoms. Currently, it has a Tc of 26K, but that would probably change.

From preliminary report, it seems that it is not phonon-mediated, but rather via spin-fluctuation. It would be interesting to see if it has the same phase diagram as the cuprates and if it also has a pseudogap state.

Update 04/18/08 : There's a rather good summary on this in a Science daily news.

Zz.

What is the Matter with the Uuniverse?

More CP violation results out of KEK on the B meson.

To find out the team created pairs of matter and antimatter particles, called B mesons and anti B mesons, and measured how they behaved. The study has come up with a better estimate of earlier measurements that suggest that there is a difference in the rate of decay (they decay into a kaon and pion).

"We have measured two differences of decay rates between b and anti-b," says Prof Hou. " It is around 9 per cent for neutral B and anti-B, and 7 per cent for charged B and anti-B. The bigger mystery, and gist of our paper, is posing the question of why there is this difference."

But the end of the article mentioned about waiting for more results out of BaBar at SLAC. I thought SLAC is no longer doing any particle collider experiment and is already being converted into the LCLS? Did something changed? Or are still going to do limited collider experiment in between LCLS runs?

Zz.

Addendum: I just finished reading the paper in Nature (Lin et al, Nature v.452, p.332 (2008)) and the Perspective on this work by Michael Peskin in the same issue of Nature. The BaBar result they are expecting is the analysis of the large, existing data that have already been collected. So it isn't from any future BaBar experiment. That clears things up a bit, at least for me.

More Addendum: See a report on this in PhysicsWorld.

HiRes Confirms GZK Cutoff

This could be one of HiRes last triumphs. It has now down a "negative result" experiment and confirms the GZK cutoff (link may be open for a limited time), signifying a threshold of energy for cosmic rays.

This energy ‘cut-off’ was predicted in 1966 by Kenneth Greisen of Cornell University in Ithaca, New York, and in the same year by Soviet physicists Georgiy Zatsepin and Vadim Kuzmin of the Lebedev Institute of Physics in Moscow. They predicted that there would be very few cosmic rays with energies greater than about 6×1019 electronvolts (eV) because of energy losses through interactions with the ubiquitous photons of the cosmic microwave background, the radiation that fills the Universe.

Zz.

The Hummer is NOT More Environmentally-Friendly Than a Prius

It's amazing how a report that is full of holes can gain such a foothold once some talking heads on TV adopted it.

A while back, there was a rather dubious report called "Dust to Dust" that essentially drew up a conclusion that the monstrous Hummer is more "environmentally friendly" than the Prius, based on all the energy accounting that is being used to research, manufacture, and run the vehicles. Slate.com has a brief synopsis of the whole thing. Luckily, they also tackled the validity of that claim and cited several prominent (and certainly, NOT dubious) research work. It essentially debunked that myth.

Moral of the story: never accept the validity of science/engineering issues from politicians, TV personalities, or popular news media.

Zz.

More Challenges Against Non-Local Hidden Variables Theory

Science Daily is reporting a new experimental measurement out of NIST and Maryland that challenges the validity of a certain aspect of non-local hidden variables theory.

Experiments so far have ruled out locality and realism as a combination. But could a theory assuming only one of them be correct" Nonlocal hidden variables (NLHV) theories would allow for the possibility of hidden variables but would concede nonlocality, the idea that a measurement on a particle at one location may have an immediate effect on a particle at a separate location.

Measuring the polarizations of the pairs of entangled particles in their setup, the researchers showed that the results did not agree with the predictions of certain NLHV theories but did agree with the predictions of quantum mechanics. In this way, they were able to rule out certain NLHV theories. Their results agree with other groups that have performed similar experiments.

I may have missed it, but I don't recall ever seeing any experiment on entanglement that hasn't produced any result that's consistent with QM. One can argue that such-and-such an experiment doesn't rule out that and that theory, but QM is batting with 100% hits here with zero strike-out. I find that rather impressive, and impressively convincing.

Zz.

Public Impatience With Science

Argonne's Director Robert Rosner spoke to the Chicago Council on Science and Technology, a not-for-profit organization is committed to promoting science and technology in the greater Chicago area. Some of the things he said bears repeating here, especially on the part where it takes decades for a basic scientific breakthrough to make it to the consumer.

Computers were around for 30 years before they became useful to business, and solid-state electronics consumer products didn't catch on until a generation after the transistor was discovered, said Rosner, director of Argonne National Laboratory.

"When a basic discovery is made, no one has any idea what it will lead to," said Rosner. And this disconnect is behind the financial crisis now afflicting Argonne and its sister institution, Fermilab.

"People believe that basic science can wait," said Rosner, "but the truth is that if you don't do the basic research today, you won't reap the fruits in 20 to 30 years. We have to invest now to benefit our children and grandchildren. But to a culture that expects instant results, such patience is a hard sell.

I think most people do forget that. Even within the sciences themselves, many forget that some of the advancement in biochemistry, for example, were brought about because of something that was developed in physics years before. Synchrotron light sources came out of research in high energy physics, and it took many decades before the field of biochemistry, medicine, and pharmacy realized that such facilities can be valuable to their work. This is just one example of something that came out of basic research that appeared to have no direct application at that time.

Just how do we convey that to the public and, especially, those politicians?

Edit: The original link appears to no longer work. However, there is a link directly to the Chicago Council on Science and Technology with a video of the talk.

Zz.