Thursday, July 31, 2008

AAC08 Day 4

OK, I'm starting to feel a bit sleep-deprived, but that's OK. We will soldier on...

The plenary session this morning started off with Phillippe Piot of Fermilab/Northern Illinois University, talking about Control and manipulation of electron beams. He covered three different aspects of this:

- maximizing beam brightness
- repartitioning of phase space between different degrees of freedom to tailor the 2D brightness for specific application, eg. FEL, mu-colliers;
- tailoring the beam's distribution along one direction.mainly along the longitudinal coordinate.

He talked about the planned emittance exchange experiment that was being planned.

This was then followed by a talk on Optical Accelerator Structures by B. Cowan (Tech-X). This is where, instead of RF structures with larger wavelengths, we are now exciting these accelerating structures using optical EM wave. This implies that with the shorter wavelength, these optical structures are tiny! He talked about various types of structures, the physics involved, and of course, the major challenges in engineering and fabricating such structures. I'm very impressed at how these things are constructed, even if they are using various advances from the electronics industries.

The last talk in the session was on Computation on new architectures by B. Albright of Los Alamos. He had a longer title than this, but I didn't write it down. This is basically a talk on advanced computing hardware. In particular, he was describing the porting of VPIC codes onto the RoadRunner supercomputer built by IBM that is now being delivered to Los Alamos.

As I listened to this presentation, the one thing that came across my mind repeatedly was "big toys for big boys". :) This thing is going to be impressive! But then again, the "big toys for big boys" can be said to almost everything being presented in this workshop.

Our banquet is tonight at the Monterey Aquarium. This should be utterly fun!


More Bad Usage of "Centripetal" Force

I mentioned earlier of the erroneous usage of centripetal force when the author actually was thinking of "centrifugal" force, fictitious or not. This is another similar situation.

I like the application and the conscious link to physics concepts in describing everyday world. This article is discussing on various ways to get the last drop of ketchup out of a bottle.

Some of the ideas are entertaining methods to demonstrate inertia and other physics principles to your dining companion. For example, you can hold the bottle by its end and swing it around in a circle as fast as you can, letting the centripetal force push the contents toward the cap.

Of course, any first year undergraduate physics students can already tell you that a "centripetal force" is a central force that acts INWARDS, towards the center of the revolution (in a circular motion). It is the force that causes the ketchup bottle and its content to move in the circular path. A ketchup in the bottle will have a friction (and viscosity) with the wall of the bottle that will transfer this centripetal force from the source of the force to the wall of the bottle to keep that volume of ketchup in motion. However, at some point, the centripetal force will be greater than the friction between the ketchup and the wall of the bottle so that the ketchup will slid outwards.

Of course, one could also use the "centrifugal force" to explain this from the reference frame of the ketchup. This is the outward force that will "push the contents towards the cap". So again, as in the previous bad usage of "centripetal force", the author had "centrifugal" force in mind but didn't use it.


Large Hadron Rap

Oy! I was going to say that now I've seen everything, but I probably haven't! :)

Someone at CERN certainly has a bit of time on his/her hands to do video editing and quite a bit of creativity to do this "Large Hadron Rap" music video. It is very funny, though. :)

Edit: I found the source of this video. :)


Wednesday, July 30, 2008

AAC08 Day 3

Another packed day here at AAC08. I missed the first few minutes of the plenary session due to a teleconferencing, but still managed to get most of the going-on early in the morning.

The plenary session started with Gregory Nusinovich covering issues surrounding structure breakdowns. It's a great presentation which basically summed up all the relevant issues that we know and still don't know about vacuum breakdown. One interesting issue that he brought up is the issue of cyclic fatigue in an RF structure due to pulse heating of the structure walls in an RF magnetic field. Basically, while a lot of attention has been focused on the oscillating E-field that can produce field-emission current, the oscillating magnetic field in the RF pulse may in fact cause significant heating and possibly induce the formation of cracks in the material. These cracks could be the source of breakdown in these structures.

The next talk was by Stuart Mangles of Imperial College on Laser Wakefield Acceleration, focusing on the diagnostics and petawatt class experiment. He presented results from a recent experiment on ASTRA at Gemini.

Warren Mori of UCLA next presented a model of particle beam dynamics in plasma accelerator, focusing especially on beam loading. This was quite an informative talk because he presented a very clear background physics on the plasma dynamics due to an electron beam, especially in the non-linear regime.

We had an unscheduled presentation by Jay Hirshfield of Yale, but it was a fascinating on. He presented the first ever experimental results for LACARA - Laser Cyclotron Resonance Accelerator - at the Accelerator Test Facility (ATF) at Brookhaven. This is where they try to accelerate electrons only using lasers, no plasma or any other medium. The experiment was done last July 14-22, so it is really new. He showed both energy loss and gain, with an energy gain by the electrons of about 2 MeV. So this is essentially a successful (and encouraging) proof-of-principle experiment.

Needless to say, it was a rather exciting ending to the plenary session.


Tuesday, July 29, 2008

AAC08 Day 2

I was asked this earlier, and I'll mention it again if someone missed the comment. The plan is for all the presentation given at this workshop to be available on the AAC08 webpage... eventually. Some sooner than later. So if you look at the workshop page often, I'm sure it'll appear somewhere. I'm guessing there will be an active link in the Program page, linking each talk to the presentation, but that's just my guess. You can already see the abstracts of the Plenary talks there.

And now, on to Day 2.

The morning Plenary session started off with Ralph Fiorito of Maryland, talking about Particle Beam Radiation Diagnostics. The problem with generating electron beam is that, how do you know what you have generated as far as its property is concerned? That's where we have various diagnostics techniques to measure things ranging from the beam emittance, bunch length, size, etc.. etc. Some of these properties are not very easy to obtain, since the electrons themselves can interact in unpredictable ways with the device measuring it. So the diagnostics isn't trivial. Fiorito described 2 different channels for charged particle radiation concepts: (i) transition radiation and (ii) diffraction radiation. He then presented direct application of incoherent and coherent radiation: near field imaging (spatial distribution) and far field imaging (angular distribution).

The next speaker was Matt Zepf of Queen's University. He presented a slightly different topic than the majority of what the attendees are used to - Laser Acceleration of protons and ions. Most of us here are more familiar with electron acceleration. He presented the physics and technology of proton/ion acceleration, and how this differ from electron accelerators.

The last speaker for today Plenary session was David Bruhwiler of Tech-X. He talked about New Development in the Simulation of Advanced Accelerator Concept. Basically it is modeling various acceleration scheme, such as laser wakefield acceleration, electron beam-driven plasma wakefield, etc.

This gives me a terrific segway into one important aspect of the accelerator physics field. Many of the structures that have to be built are often either big, complicated, expensive, time-consuming, or a combination of all of these. We can't simply build one and test it, and if it doesn't work, build another one. We have to try and build one that will do close, if not exactly, what we want, or else we have spent a lot of money and effort in building something useless. That's why a huge section of accelerator physics is computer simulation and modeling. The computational aspect of accelerator physics is extremely crucial in our ability to design and simulate the various structures that we want to build first before we build it. It is only when the various numerical codes and packages can give us the confidence that we have designed something that can possibly work do we build it and test it to confirm that our simulation was accurate.

The point here is that there's a tremendous opportunity for someone who is interested in computational physics to be extremely valuable in this field. I don't think many people, especially students, realize that.

Back to AAC08.

The late morning and afternoon sessions signal the start of the "backbone" of the AAC workshop - the Working Group sessions. This is where participants break off in various working groups centered on specific areas within accelerator physics (see the webpage for the list of all the working groups).

I went into the High Gradient Structures working group where the morning and afternoon sessions were dedicated to breakdown issues in high-gradients, including various modeling and possible triggers that starts a RF vacuum breakdown. SLAC group presented an enormous amount of observational data on various conditions where breakdown occurs. The afternoon session also included presentation on computational model (there it is again!) that tries to track or describe multipactor in an RF field.

By the end of the session, I was pooped!


Monday, July 28, 2008

AAC08 Day 1

It was a long but interesting first day. The agenda was filled with plenary sessions, and the afternoon student poster session/competition.

The workshop was opened by high-energy physicist Hitoshi Murayama of IPMU-Tokyo and UC Berkeley. His talk was on the physics beyond the LHC. Basically he was giving a brief tutorial of high energy physics (both accelerator based and in particle astrophysics) and what to expect beyond the LHC. The motivation here was to give an idea to particle accelerator community what kind of technology that one can start to expect as soon as the first set of results from the LHC comes in.

The one thing that he kept emphasizing, possibly because of the crowd that he was addressing, was that particle accelerators have been THE enabling technology for particle physics. He emphasized that many non-accelerator physics discoveries had to be confirmed, studied, and improved using accelerators.

Murayama then established why the TeV energy scale is so crucial. This is the scale that corresponds to a length scale of 10^-17 cm, which is the scale of the short-ranged weak force. He actually described why the ILC is needed even if the LHC sees signature of the the Higgs (or many different types of Higgs). The ILC would produce a "cleaner" signal to allow high energy physicists to narrow down the Higgs properties that the LHC would find.

All in all, it was an effective "fan mail" from high energy physics community to the accelerator physicists. :)

The second talk in the morning plenary session was by Tor Raubenheimer on the Future R&D for Very High Energy Colliders. He basically listed the relevant parameters of the accelerator technology that is needed beyond the LHC. This essentially mirrors the ILC technical report, and the recent P5 report from last June. It boils down to these 2 numbers for the ILC:

1 TeV and luminosity of 1 x 10^34 cm^-2 s^-1

The estimated cost in 2020 dollars (assume an inflation of 3.5%) is $20-25 billion. The majority of the cost (60%) is estimated to be in the main linac section. So the acceleration scheme costs the most. Finding something that can substantially lower the cost of the accelerating section would substantially lower the total cost.

Next to talk was Pisin Chen of Kavli Institute/SLAC on Laboratory Astrophysics. He talked about particle astrophysics, dark matter, and high energy-density physics. He also argued that intense laser field in an electron accelerator can, in fact, probe the Hawking-Unruh effect.

Chris Barty of LLNL described the current status of the Livermore's laser technology (he jokingly described LLNL to not mean Lawrence Berkeley National Laboratory, but rather Laser, Laser, and Nothing but Laser). He spent quite a bit of time describing the laser system at the National Ignition Facility. That facility is obscenely impressive. I mean, anyone who is familiar with high-powered laser can't help but be impressed by what they have done there. It's just a jaw-dropper of the technical difficulties that they faced and have overcome. He also showed a video on how they actually used a laser with a spot 4 inch x 4 inch and simply melted a thickness of aluminum in seconds! Holy Cow!

Cameron Geddes of LBNL then proceeded next to describe all the progress made in laser-driven plasma wakefield acceleration scheme. This is the scheme that has made significant progress (and publicity) in achieving huge gradients. It is simply amazing the amount of progress that has been accomplished in this field, and they continue to refine the technology. This is a serious contender for the next acceleration scheme in future generation of particle accelerators.

After the lunch break, Wei Gai from Argonne described the Advanced Accelerating Structure and their interactions with electron beam. Basically it reviewed the effect of electrons passing through dielectric-loaded accelerating structure, photonic band-gap structure, and meta-material/left-handed structures.

Tom Katsouleas (who used to be at USC but is now at Duke University) described another type of plasma wakefield scheme. This time, instead of laser driven which was described by Geddes, it is electron-beam driven. This is where a bunch of electron passing through a plasma can create an accelerating wakefield for a witness beam that follows it. The current demonstration has shown the acceleration of an electron bunch from 42 GeV to 85 GeV in 1 m. That's pretty impressive. He also spent time showing a realistic concept of plasma wakefield accelerator for a linear collider, a facility that is being set up at SLAC.

I spent some time going around the student's poster session, which occupied 3 different rooms. The judges were already going around to different posters. Good luck to all the students!


More On The Naming Spat At SLAC

Here's more news report regarding the use of the name "Stanford" in SLAC and the DOE's requirement of trademarking the name of its National Labs. It is resulting in the possible renaming of SLAC.

Stanford officials who insist the government can't copyright the venerable university's name have countered with an offer that would give federal officials a royalty-free "perpetual" license to use the Stanford and SLAC names.

"SLAC's record is pretty distinguished, and with the university's offer of a license to use the Stanford name, what more do they need?" said Burton Richter, SLAC's former director and one of the Nobelists who won his prize there. "I'm really bewildered."

I wonder if DOE already got a trademark for the Princeton Plasma Physics Lab? I would imagine it doesn't have the same issue here since "Princeton" is a city, unlike "Stanford".


Sunday, July 27, 2008

AAC08 Day 0

Greetings from Santa Cruz, CA!

I arrived early this afternoon for the registration. Just got back from the evening reception dinner. People were slowly streaming in from all over the world.

The resort is rather gorgeous, high up in the hills overlooking Santa Cruz. All the sessions will be held at the resort's conference center, so those of us who are staying at the resort will find that to be rather convenient.

The first day of the workshop will start bright and early tomorrow. There should be several plenary talks tomorrow. So there should be plenty to report on.


Saturday, July 26, 2008

Defending Your Ph.D Thesis With Flair

In my "So You Want To Be A Physicist" essay, I described a bit on the preparation leading up to one's thesis defense. It never hurts to have another point of view (and similar ones) on this. Science has an article that covers the very same topic this week in the career development section. It covers a little bit more the general preparations for one's defense, and also what one should do during the defense. It certainly is a recommended reading for anyone about to go through the process.


Preparing for AAC08

I will be flying off to California tomorrow to attend the 2008 Advanced Accelerator Concepts Workshop (the webpage seems to be down this morning). The host for this year's workshop is the Lawrence Berkeley National Lab, and it will be held at the Chaminade resort in Santa Cruz, CA.

From the agenda, this should be quite a workshop, and certainly at a rather critical point in terms of planning for future directions. With the ILC having a delayed and uncertain future, and future particle colliders not really something anyone is willing to pay for, there's even a greater need for advancing the accelerator technology to produce more efficient, compact, and less costly alternatives, or in some case, improving the current technology to work beyond the present-day limitations.

I will try to report on some of the presentations there as the workshop progresses. Hopefully, it will be exciting enough for people to want to read. :)


Friday, July 25, 2008

Phase Transitions of Dirac Electrons in Bismuth

And amazing and elegant experiment out of Princeton published in the latest edition of Science.

Abstract: The Dirac Hamiltonian, which successfully describes relativistic fermions, applies equally well to electrons in solids with linear energy dispersion, for example, in bismuth and graphene. A characteristic of these materials is that a magnetic field less than 10 tesla suffices to force the Dirac electrons into the lowest Landau level, with resultant strong enhancement of the Coulomb interaction energy. Moreover, the Dirac electrons usually come with multiple flavors or valley degeneracy. These ingredients favor transitions to a collective state with novel quantum properties in large field. By using torque magnetometry, we have investigated the magnetization of bismuth to fields of 31 tesla. We report the observation of sharp field-induced phase transitions into a state with striking magnetic anisotropy, consistent with the breaking of the threefold valley degeneracy.

L. Li et al. Science v.321, p.547 (2008).

There is a Perspective article on this work in the same issue of Science, and a Science Daily review. This is another example of how relativistic equations are applicable to materials that could be sitting on one's desk or being used in modern electronics, and not just to some esoteric experiments.


Thursday, July 24, 2008

Is Faith The Enemy Of Science?

As I've mentioned a few times on here, I seldom want to highlight a non-published paper on arXiv because, well, it is not published and that some time we get rather dubious stuff being uploaded there.

Still, now and then, there are rather interesting preprints and articles that either have been submitted for publication and in the review process, or articles that are just plain fun to read. And once in a while, you get something that is quite provocative and no-less entertaining to read. This is one such article.

Richard MacKenzie of the University of Montreal has written a rather thought-provoking and lengthy article as a rebuttal to a talk given by Lawrence Krauss. In it, he is disputing Krauss's assertion that:

Faith is not the enemy.
Ignorance is the enemy.

MacKenzie argued that the reverse is more valid, that Ignorance is an opportunity to educate by starting from a clean slate, while Faith requires more effort to correct what has already been accepted. He made further discussion on the idea of scientists who also accept the validity of religious faith.

You just have to read it and see if this doesn't perk up your interest. :)


Cow Power Could Generate electricity for Millions, Study Shows

Before you proclaim that this report stinks, you should read it carefully. :)

Scientists at the University of Texas (of course) has published a report that claim that by burning the manure from cows and other livestock, the US could get could get as much as 3% of electricity demand.

Broken down and then burnt, the scientists estimate that the manure from hundreds of millions of livestock in America could produce approximately 100 billion kilowatt hours of electricity a year.

If left to decompose naturally manure releases noxious gases into the environment, some of which warm the atmosphere at a higher rate than carbon dioxide.

Converting it to power could reduce those emissions by 99 million metric tonnes, the equivalent of approximately four per cent of America's emissions from electricity production.

Although the process would emit some carbon dioxide into the atmosphere, it would do so at a lower rate than if coal was used.

While such a claim isn't new, the numbers being presented here is unHERD of previously. I certainly don't think this is UDDER nonsense, but it might be worth looking into.


Edit: Here is the exact reference to this work:

Amanda D Cuéllar and Michael E Webber, Environ. Res. Lett. v.3 p.034002 (2008)

Abstract: This report consists of a top-level aggregate analysis of the total potential for converting livestock manure into a domestic renewable fuel source (biogas) that could be used to help states meet renewable portfolio standard requirements and reduce greenhouse gas (GHG) emissions. In the US, livestock agriculture produces over one billion tons of manure annually on a renewable basis. Most of this manure is disposed of in lagoons or stored outdoors to decompose. Such disposal methods emit methane and nitrous oxide, two important GHGs with 21 and 310 times the global warming potential of carbon dioxide, respectively. In total, GHG emissions from the agricultural sector in the US amounted to 536 million metric tons (MMT) of carbon dioxide equivalent, or 7% of the total US emissions in 2005. Of this agricultural contribution, 51 to 118 MMT of carbon dioxide equivalent resulted from livestock manure emissions alone, with trends showing this contribution increasing from 1990 to 2005. Thus, limiting GHG emissions from manure represents a valuable starting point for mitigating agricultural contributions to global climate change.

Anaerobic digestion, a process that converts manure to methane-rich biogas, can lower GHG emissions from manure significantly. Using biogas as a substitute for other fossil fuels, such as coal for electricity generation, replaces two GHG sources—manure and coal combustion—with a less carbon-intensive source, namely biogas combustion.

The biogas energy potential was calculated using values for the amount of biogas energy that can be produced per animal unit (defined as 1000 pounds of animal) per day and the number of animal units in the US. The 95 million animal units in the country could produce nearly 1 quad of renewable energy per year, amounting to approximately 1% of the US total energy consumption. Converting the biogas into electricity using standard microturbines could produce 88 ± 20 billion kWh, or 2.4 ± 0.6% of annual electricity consumption in the US. Replacing coal and manure GHG emissions with the emissions from biogas would produce a net potential GHG emissions reduction of 99 ± 59 million metric tons or 3.9 ± 2.3% of the annual GHG emissions from electricity generation in the US.


There's a Lot More to Going Fast Than the Horsepower Number

I think every physics student would know that. Still, this article on this particular vehicle called the "Atom" tries to illustrate why the vehicle's mass, and not just the "horsepower", certainly dictates how fast a vehicle can go and how quickly it can reach very high speeds.

The details of the physics lesson is that 200 horsepower doesn't sound like much, but when the car weighs less than 500 kilograms? Step up to the supercharged model like the one you see here and you get 300 horsepower, enough to launch the Atom to 100 km-h in three seconds.

But still, did anyone else caught the unintended pun early in the article? I'm guessing that even the writer didn't notice it.

That seems odd as you sit so low in the Atom, and you're so exposed to the elements with wind rushing up your legs through the sides of the car that it feels as though you're travelling twice as fast as you actually are.

Do you see it? Atom.... exposed to the elements.... Oh, never mind!



Wednesday, July 23, 2008

Taleyarkhan Plans To Appeal

As I've said when I reported the latest Purdue findings of scientific misconduct against Taleyarkhan, this will not be the end of it. And so it isn't. Taleyarkhan plans to appeal against the scientific misconduct finding by Purdue.

Purdue gave Taleyarkhan 30 days to appeal the committee’s verdict. According to his lawyer, he plans to do so. "There are a number of facts and issues that were not allowed in the inquiry, and the other nuclear engineers involved are all in complete support for Taleyarkhan," John Lewis of the Indianapolis law firm Lewis and Wilkins told Physics World. "Xu maintains to this day that Butt’s involvement was his choice. But that part of Xu's testimnony was completely ignored."

... and so it goes.


Newtonian Gravity Still Holds At 10 Microns

So where are all these extra dimensions?

A new report out of Stanford has now made an even more stringent test for Newtonian gravity all the way down to 10 microns[1]!

It has been proposed that if there are extra dimensions for gravity to propagate, then at some very small distances, gravitational strength will start to deviate from the known Newtonian description. Originally, there were proposal that this deviation might be at the millimeter scale. That has been blown out of the water. There has been progressively smaller and smaller length scales over which gravity has been checked, and this latest report is the smallest as of now.

So really, where are these extra dimensions already!


[1] A.A. Geraci et al. Phys. Rev. D v.78, p.022002 (2008).

Quantum Physics Makes Water Different

It is interesting that one of the substance that we are most familiar with, actually can only be explained using quantum mechanics. This is certainly true with water and its properties.

Quantum objects, such as atomic nuclei, have properties of both waves and particles. Quantum effects aren’t usually manifest to the naked eye, but in this case they may be responsible for some of water’s unusual features. “The quantum effect in water is abundantly obvious,” says Alan Soper of the Rutherford Appleton Laboratory in Didcot, England.

So if anyone wants to know where QM can be applied to, point to them the stuff flowing out of their taps.

I'll find the actual paper that this was published and put the reference here.


Tuesday, July 22, 2008

The Physics of Sandcastle

Even at the beach, you can still learn about science/physics. Now you can understand the science behind sandcastles.

So why don't you go read that while I get my daily dose of sun and sand... {yawn.....}


Monday, July 21, 2008

Argonne Scientist to Become ATLAS Physics Coordinator for CERN - Part 2

Please read this entry for Part 1 of this Q&A session with Tom LeCompte

3. Would ATLAS be able to detect signatures of any micro blackholes if such a thing is created?

Tom: If you asked me six months ago, I would have had a more definite answer. A lot of people have been asking the question, "If there are mini black holes, would their signature be sufficiently above the background that they can be detected?" The answer to that question is, for a large range of parameters, "yes". Now people are asking the question, "If there are mini black holes, would we be able to tell that's what they were, as opposed to something else?" That turns out to be a harder problem - especially right after any sort of discovery, because almost by definition you have very few events. (If you have a lot of events, you would have discovered it sooner - back when you had fewer). We have a lot of people working on this now, but I think the conclusion that it takes more data to figure out whether the new physics is a black hole or something else than it does for the initial discovery is probably always going to be the case.

4. Having been at CERN many times, how do you find living situation there when compared to where you are presently?

Tom: Geneva is a wonderful city, but very, very expensive. The weather takes some getting used to: when I was learning French, the first complex thought I was able to express in French was about the weather in Geneva: "Il neige en hiver et il pleut le reste du temps" - which means "It snows in winter and rains the rest of the time."

5. Other than the Chicago deep dish pizza, what will you miss most after your move to CERN?

Tom: Well, this year I am going to miss the cross-town world series!

Ah, ever the eternal optimist, that Tom. That's why we like him!



Sunday, July 20, 2008

Argonne Scientist to Become ATLAS Physics Coordinator for CERN - Part 1

ATLAS is one of the detector already ready to go at the LHC. Tom LeCompte will be starting as deputy physics coordinator for ATLAS before moving up to the coordinator position the following year.

The ATLAS Collaboration Board recently approved the appointment of LeCompte as deputy physics coordinator of the ATLAS experiment. He will be deputy starting Oct. 1 for one year and then become physics coordinator on Oct 1, 2009.

I was privileged to be able to ask Tom a few questions not only about his new job and move to CERN, but also on the physics issue. So here is Part 1 of my Q&A with him.

1. What will be your primary function as the science coordinator of ATLAS?

Tom: I start as Deputy Physics Coordinator, under the Physics Coordinator who is presently Professor Dave Charlton of the University of Birmingham. So for a year, it's easy - I do whatever he tells me to do. The following year, I become the Physics Coordinator. Ultimately, we're responsible for the physics results in the experiment - they obviously have to be correct, but they also have to be timely.

There's a certain amount of coordination out there. Suppose you have one group that is measuring events of a particular type - call it A. They pick a reasonable way to select their events. Now suppose there is another group measuring B, and they pick a different reasonable way. Now C comes along, and this group realizes that A and B are backgrounds to the events they are interested in. But they can't simply combine them, because they were selected differently. So they have to repeat the work of at least one of the two groups. Commonality across different analyses can save time, and reduces the chance of making a mistake, so we want to encourage this. On the other hand, we don't want to squelch individual creativity, so there's a balance we have to strike.

There are also cases where we have to prioritize. After we will have run for a while and gained some experience, our reconstruction algorithms will naturally improve. We will want to rerun them on the data we have already taken, a process that takes a couple of months. The experiment will have to decide which events to process first (not everybody can be first) and physics coordination will have to forge this consensus.

As you might imagine, getting 2000 people to work together on a scientific experiment without accidentally getting in each other's way is not something that happens automatically.

2. Besides the search for the Higgs (or many Higgs) boson, what other physics can be studied with ATLAS?

Tom: I don't really like calling it "the Higgs search", because it presupposes the answer. The problem is understanding what we call "electroweak symmetry breaking", which is a fancy name for "why are the W and Z bosons so heavy when the photon is so light", or alternatively, "why is the weak force so weak and so short range, while the electromagnetic force is long range and powerful." One possible answer is that there are one or more Higgs bosons. Another is that the W's and Z's interact very strongly at short distances and form resonances and these resonances break the symmetry. A third possibility is that the top quark, much heavier than the other five quarks, places a special role in this. There are many variations on these basic ideas, and as experimenters our job will be to gather the evidence that lets us distinguish between the various possibilities.

So, here's an incomplete list of some of the things we will have to do - besides figuring out what's up with electroweak symmetry breaking: We will need to understand the structure of the proton, because we collide beams of protons and we need to understand our initial state. We will need to make precision measurements of quantities well predicted by today's theories, to look for inconsistencies: these inconsistencies will point us in the direction of the new physics. We will need to search for new particles and new phenomena, and because the LHC has more energy than any previous accelerator, it's a likely place to look. We will need to better study the properties of the top quark, because we will have thousands of times more of them than the existing experiments. Finally, for about one month out of the year, instead of beams of protons we will collide beams of atomic nuclei, and that will let us study the properties of hot, dense nuclear matter, which behaves very differently than ordinary nuclei.

You can see that 2000 people sounds like a lot, but there are many things we will have to measure - by the time you are done dividing things up, it's not as many as you would think.

Stay tune for Part 2.


LHC First Beam Might Be Delayed Due To......

.... the olympics!

At least that's what being reported here as a possibility (i.e. this is still a rumor and should not be blown out of proportion for what it is).

"During the month of August the first beam will be injected into the LHC," Evans said confidently, and later added that it will probably mid August.

Meanwhile, one CERN official quietly suggested a different window: the last week of August or the first of September. The reason for this discrepancy? In mid August CERN will not be able to get hold of a satellite uplink to televise the switch-on because of the Olympics, which is hording them all. So CERN's media office is pushing for a slight delay so the world can better see LHC's successful start....

Ah, the joy of doing science....


Saturday, July 19, 2008

PPPL Gets A New Director

The Princeton Plasma Physics Lab will get a new Director. Princeton has announced that Stewart Prager from U. of Wisconsin-Madison (my alma mater) will be the new director of the DOE lab.

Prager, who also is the Dexter Professor of Physics at Wisconsin, will become the sixth director of the laboratory, which is funded by the DOE and managed by the University. His appointment as a professor of astrophysical sciences at Princeton is expected to be acted on in the fall.


Friday, July 18, 2008

Global Warming Opponents Have Gone Bonkers! - Follow-Up

As a follow-up to my entry on Global Warming detractors who are in joyful mood when the APS's Forum on Physics and Society had a newsletter that included a "debate" on global warming, the July 18, 2008 edition of Bob Park's What's New has an even more eloquent comment on this:

Science is open. If better information becomes available scientists rewrite the textbooks with scarcely a backward glance. The Forum on Physics and Society of the APS exists to help us examine all the information on issues such as global climate change. There are physicists who think we don't have warming right, I know one myself. It is therefore entirely appropriate for the Forum to conduct a debate on the pages of its newsletter. A couple of highly-respected physicists ably argued the warming side. Good start. However, on the denier's side was Christopher Monckton, 3rd Viscount Monckton of Brenchley, who inherited his father's peerage in 2006. Lord Monckton is not a scientist, his degree is in journalism and he's a reporter for the Evening Standard, an English tabloid. Whatever it is that Viscounts do, he may do very well, but he doesn't know squat about physics and his journalism suffers from it. Worse, somebody fed the media the line that Monckton's rubbish meant the APS had changed its position on warming; of course it has not. Few media outlets took the story seriously.

and I was thinking (yes, I do that some time, especially when the moon is full). I recall that when Al Gore was criticized by global warming opponents as not being a scientist when he presented his global warming "disaster movie" in Inconvenient Truth. How come they don't go after Monckton, who isn't a scientist either? And if these people are so impressed that the APS "appears" to change their stand on global warming, how come they are not as impressed when the APS actually made its initial stand (and continues to hold the same opinion) on global warming?

All I see here is that some people are picking and choosing what they want to believe. If they put that much credibility in the APS that by simply having a "dialog" on global warming gave global warming opponents some form of "credible" ally, then how come they also don't put the same amount of credibility on all the other previous issues that the APS and AIP have strong and very clear opinions on? Evolution, anyone? And last time I checked, the AIP still has a webpage with very clear opinion (and a series of peer-reviewed references) on their stand regarding global warming. How come they IGNORE such thing, while grabbing what I've said as the flimsiest of threads?

It makes no sense.


Purdue Declares That Taleyarkhan Guilty of Scientific Misconduct

In a complete about-face, Purdue has released its latest finding on the Taleyarkhan debacle. After an earlier investigation that found no misconduct, the most recent (and presumably, more encompassing investigation) has found him guilty of scientific misconduct.

Purdue University announced today that one of its nuclear engineers was guilty of scientific misconduct in work related to his potentially revolutionary findings about creating fusion from bubbles.

The announcement represented an about-face for the university, which more than a year ago declared that the scientist, Rusi P. Taleyarkhan, was not guilty of misconduct. The university had come under fire from members of the U.S. House of Representatives for that earlier assertion, and subsequently started a new investigation.

Do I think this is the end of this thing? Nope. I'm sure Taleyarkhan will appeal and/or both sue the university.

Edit: more coverage of this by the Science Daily News update.


No More SLAC

I read this in this week's issue of Science (18 July, 2008). It seems that the name "Stanford Linear Accelerator Center" may be gone soon, and it has nothing to do with the fact that it is no longer a particle collider facility.

The Stanford Linear Accelerator Center (SLAC) in Menlo Park, California, will change its name. That’s because the Department of Energy (DOE) wants to trademark the names of its 17 national labs, and Stanford University won’t let DOE claim its name. The impasse is “an example of DOE idiocy,” says Nobelist and former SLAC Director Burton Richter, because the university would protect the name anyway. But DOE has been pushing to trademark lab names for more than a decade, spurred in part by a new law allowing trademark suits against the government, a risk DOE says it is trying to minimize.

Oy vey!


Global Warming Opponents Have Gone Bonkers!

It is amazing how, just by having a discussion about it, some people have gone way over the edge and proclaim something a nanometer short of victory. Holy cow!

Now, I mentioned earlier the APS Forum on Physics and Society's July newsletter, that included a discussion on Global Warming issues. I highlighted the WHOLE newsletter, so that you can see the content, especially the two papers that have rather opposite views on Global Warming. I didn't want you to just read one without the other.

However, various rabid anti-global warming sites and blogs have somehow taken such open discussion and ran away with it. This website even proclaimed that "The Myth of Consensus Explodes". The same goes with this blog entry. They are just going ga-ga with the flimsiest piece of thread that somehow, a branch of the APS (of which I am a member of - both the APS and the division of Forum on Physics and Society) would open a discussion on such an issue.

But here's the thing - did they actually READ the papers? There are two problems with the kind of "reporting" that was done here:

(i) They never mentioned about the OTHER article by David Hafemeister & Peter Schwartz in the SAME issue of the newsletter that draws up very clear conclusion:

Earth is getting warmer. Basic atmospheric models clearly predict that additional greenhouse gasses will raise the temperature of Earth. To argue otherwise, one must prove a physical mechanism that gives a reasonable alternative cause of warming. This has not been done. Sunspot and temperature correlations do not prove causality.

This omission is misleading at best, and dishonest at worst. They highlighted ONLY the article by Christopher Monckton.

(ii) and speaking of the Monckton article, here's the conclusion that he came up with:

Even if temperature had risen above natural variability, the recent solar Grand Maximum may have been chiefly responsible. Even if the sun were not chiefly to blame for the past half-century’s warming, the IPCC has not demonstrated that, since CO2 occupies only one-ten-thousandth part more of the atmosphere that it did in 1750, it has contributed more than a small fraction of the warming. Even if carbon dioxide were chiefly responsible for the warming that ceased in 1998 and may not resume until 2015, the distinctive, projected fingerprint of anthropogenic “greenhouse-gas” warming is entirely absent from the observed record. Even if the fingerprint were present, computer models are long proven to be inherently incapable of providing projections of the future state of the climate that are sound enough for policymaking. Even if per impossibilethe models could ever become reliable, the present paper demonstrates that it is not at all likely that the world will warm as much as the IPCC imagines. Even if the world were to warm that much, the overwhelming majority of the scientific, peer-reviewed literature does not predict that catastrophe would ensue. Even if catastrophe might ensue, even the most drastic proposals to mitigate future climate change by reducing emissions of carbon dioxide would make very little difference to the climate. Even if mitigation were likely to be effective, it would do more harm than good: already millions face starvation as the dash for biofuels takes agricultural land out of essential food production: a warning that taking precautions, “just in case”, can do untold harm unless there is a sound, scientific basis for them. Finally, even if mitigation might do more good than harm, adaptation as (and if) necessary would be far more cost-effective and less likely to be harmful.

In short, we must get the science right, or we shall get the policy wrong. If the concluding equation in this analysis (Eqn. 30) is correct, the IPCC’s estimates of climate sensitivity must have been very much exaggerated. There may, therefore, be a good reason why, contrary to the projections of the models on which the IPCC relies, temperatures have not risen for a decade and have been falling since the phase-transition in global temperature trends that occurred in late 2001. Perhaps real-world climate sensitivity is very much below the IPCC’s estimates. Perhaps, therefore, there is no “climate crisis” at all. At present, then, in policy terms there is no case for doing anything. The correct policy approach to a non-problem is to have the courage to do nothing.

After reading the article, and with this conclusion, the best that I can come up with is that he is claiming that non of the global warming evidence and scenario are air tight. Well, duh! That's like people arguing that the Big Bang theory shouldn't be taught because we have no air tight evidence that it did happen, or that evolution should be adopted in schools because there's no solid "evidence" for it. (BTW, did any of these blog sites also conveniently missed the two solid articles reviewing Evolution versus Creationsm?)

With that kind of parameters and phase space, such lack of definite certainty is a given! However, the question here isn't whether they are a certainty, but rather whether they are credible enough to be considered valid. There are a lot more evidence pointing to the validity of the conclusion by Hafemeister & Schwartz than to Monckton. That is a FACT.

But the scariest part in all of this is the suggestion that we should just continue doing nothing. In other words, why don't you continue smoking that cigarette until we have definite, conclusive proof that it really isn't good for your health. Or, why don't you continue to take this drug while we sort out all of this contradicting claims that it can either kill you, or make you the healthiest person on earth. So why don't you continue to pollute the world that we live in until, you know, we completely agree on the fact that we are really killing our planet.


Thursday, July 17, 2008

The Physicist and the "Nerd" Image

Frankly, I am extremely tired of this image of a physicist. Y'know, white lab coat, pocket protector, thick glasses, mismatch shoes and socks, etc...etc. And let me tell you this. Where I work, the only person that I know of that actually has a set of pens and stuff in the shirt pocket is an engineer! :)

So I'm sure that this was meant to be 'funny', even in Singapore:

Sec 4 student Ian Yap, 16, dressed as a physicist and won the prize for 'Most Nerdy' costume.

He said proudly: 'In order to win a prize for being nerdy, you can't just dress as a nerd! You need to truly understand the ways of the nerd.'

I guess in the scheme of things, this really is a non-issue. But truly, it is also a reflection of the fact that many people simply do not encounter physicists, much less how they work and what they do, that often or at all. So the image of a "nerd" is certainly ingrained in people's mind, especially when it is being re-enforced by popular media, movies, and TV shows.

So are there physicists that actually fit into such nerdy stereotypes? Of course there are, and there are nerdy people in political science, sociology, psychology, music, etc.. etc.. as well! But one would be surprise to see just how "un-nerdy" physicists as a group are. I mean, George Bush looks downright nerdy when you put him next to Lisa Randall! Well, OK, so that wasn't such a fair comparison, but you get the point! :)


Wednesday, July 16, 2008

NASA Contractor Wants You To Pee

.. but only if you are at the Johnson Space Center in Houston.

Space program contractor Hamilton Sundstrand is seeking urine from workers at the Johnson Space Center in Houston, Texas, as part of its work on the new Orion space capsule that eventually would take astronauts to the moon, according to an internal memo posted on the Web site

The need is voluminous: 30 liters a day, which translates into nearly 8 gallons. Even on weekends.

I'd say give them plenty of stuff to drink, especially coffee. Caffeine is a wonderful diuretic for me. :)


Hawking 'Open' to a Move to Ontario

Hum... it seems that everyone is moving to Canada! :)

Stephen Hawking is leaving open the possibility of him leaving Cambridge and moving to the Perimeter Institute in Ontario, CA. This would be the biggest coup for PI since getting Neil Turok.

It certainly appears that several institutions in Canada are aggressively recruiting some of the world's most prominent physicists. George Sawatzky, a prominent condensed matter physicist, went to UBC several years ago. And recently, UBC even managed to snag Nobel Laureate Carl Wieman.

All I can say is, good for them! Obviously, they have the resources to get these people, and they know the importance of having them there. UBC certainly has elevated their stature in condensed matter many folds in recent years to become one of the most respected programs in the world.


Tuesday, July 15, 2008

Forum on Physics and Society July 2008 Newsletter

The July 2008 Newsletter of Forum on Physics and Society is now available online.

Several good articles this month, especially a couple of tutorial on the physics of global warming. There's also a review of a couple of books on evolution versus creationism. So plenty of things to read.


A New Frontier for Title IX: Science

Looks like the perceived "discrimination" and imbalance of women in the sciences are getting some attention in the US Congress.

It is still highly controversial, of course, on whether there really is some form of bias, intended or not, against having women in science, and especially in physics.

They remain a minority in the physical sciences and engineering. Even though their annual share of doctorates in physics has tripled in recent decades, it’s less than 20 percent. Only 10 percent of physics faculty members are women, a ratio that helped prompt an investigation in 2005 by the American Institute of Physics into the possibility of bias.

But the institute found that women with physics degrees go on to doctorates, teaching jobs and tenure at the same rate that men do. The gender gap is a result of earlier decisions. While girls make up nearly half of high school physics students, they’re less likely than boys to take Advanced Placement courses or go on to a college degree in physics.

These numbers don’t surprise two psychologists at Vanderbilt University, David Lubinski and Camilla Persson Benbow, who have been tracking more than 5,000 mathematically gifted students for 35 years.

They found that starting at age 12, the girls tended to be better rounded than the boys: they had relatively strong verbal skills in addition to math, and they showed more interest in “organic” subjects involving people and other living things. Despite of their mathematical prowess, they were less likely than boys to go into physics or engineering.

I think that there is one important point that those who are trying to push a policy one way or the other onto this group of people, who are scientists. These scientists tend to also be experts in the nature and validity of the "evidence" being used. So don't expect them to simply sit back and accept all of these various conclusions being forced onto them. If you think that there's a valid evidence for something, it better be something stronger than just some anecdotal evidence, or else it will be challenged.


Monday, July 14, 2008

The APS Introduces "Physics"

The American Physical Society (APS) is introducing a new publication today, simply called "Physics".

Anyone who has recently glanced at a library shelf of physics journals or browsed the literature online will instantly recognize both the increase in volume and the fragmentation of disciplines. How can a researcher stay on top of his or her own field, much less stay abreast of related areas that might harbor interdisciplinary gems? One way is to seek the counsel of experts, and so we begin a new publication, simply called Physics. Our goal is to highlight exceptional papers within the body of excellent research that the American Physical Society publishes each year in all of the Physical Review journals.
Why Physics? We feel that it fills an important niche in the Physical Review ecosystem. At the core we have the exceptional research published by the Physical Review journals and Physical Review Letters, some 18,000 peer-reviewed papers last year. To bring this work to wider notice, every week the American Physical Society alerts journalists to these exciting research papers, to stimulate coverage in print and electronic news media. And broadening the audience further, the online website Physical Review Focus highlights research papers each week in short articles written by professional science writers. Physics now satisfies the need for comment and context written by independent scientific experts, for physicists and those in related fields.

I guess this is like the APS Focus, but covering a wider subject range and a lot more of the papers that have appeared in their publications. This certainly isn't a bad idea, considering that Nature and Science do this routinely for many of the articles that appear in their journals.


CERN Council Looks Forward to Imminent Start-Up of the LHC

A more up-to-date progress report on the impending start-up of the LHC. This includes the safety analysis that was completed recently on the LHC that was reported here earlier.

The latest review of the safety of the LHC’s collisions was prepared by the LHC Safety Assessment Group (LSAG), which comprises scientists at CERN, the University of California, Santa Barbara, and the Institute for Nuclear Research of the Russian Academy of Sciences. The LSAG report updates a 2003 paper by the LHC Safety Study Group and incorporates recent experimental and observational data. It confirms and strengthens the conclusion of the 2003 report that there is no cause for concern. Whatever the LHC will do, nature has already done many times over during the lifetime of the Earth and other astronomical bodies.

... which has been my contention all along.


A Cosmic Conundrum

This is a wonderful review of the book "The Mystery of the Missing Antimatter" by Helen Quinn and Yossi Nir. I always like reading a book review where the reviewer also provide ample background information of what is covered in the content, and not just simply review the book. This is what Lincoln Wolfenstein did in reviewing this book. In the process, the reader is brought up-to-date on the issue surrounding the matter-antimatter asymmetry that we see in our universe. So this review is also a review of the subject matter for non-physicists or those not that familiar with this "conundrum".

Helen Quinn, by the way, is the author of an article that I highly recommend people to read. So she certainly is one of those rare physicist who has the ability to write succinctly and clearly. I'm very much tempted to buy this book soon.


Saturday, July 12, 2008

Newspaper Advertises Dubious (Crackpottery?) Physics

Recall that I've always maintained that many in the public cannot tell the difference between legitimate, scientific work versus anecdotal and pseudoscience (even downright crackpottery) work. I also don't care about advertising crackpot theories on this blog. But this one is rather annoying on many level that I simply had to mention it.

The Huntsville Times (presumably published in Huntsville, Alabama, which btw, has a large NASA presence there, so they should know better) in its infinite wisdom, decided to "advertise" a talk by this retired engineer that has made rather grandiose claims (always a red flag if ever there is any).

DuVall said he became interested in the problems tackled by Einstein and other physicists, and spent a lot of time pondering them.

"Einstein worked for 17 years trying to interrelate gravitational, electric and magnetic fields," he said, but the physicist never succeeded.

DuVall said he thought he saw a way to link them mathematically, and has made some presentations, including talks at the University of Arkansas, his alma mater. Challenges by skeptics led him to do more work, and the result will be presented Sunday. "No math above high school algebra," he promised.

Maybe he was an engineer and people seem to give him a bit more "credibility", but that doesn't give him a free pass from being required to go through the same scrutiny, such as publishing his ideas in respectable peer-reviewed journals. Has he done it? Just read another of this red flag:

DuVall has self-published a number of books, including one on gravity last year, and, basically, says he has amended some of Newton's Laws so they're based more on energy than on force.


Not only that, there's just something wrong with the whole ".... amended some of Newton's Laws so they're based more on energy than on force...." claim that any physics undergraduate can spot from a light-year away. One can derive ALL of the equation of motion of a system via the Lagrangian/Hamiltonian mechanics, and obtaining the same result as Newtonian force-law equations. And Lagrangian/Hamiltonian mechanics deals with energy issues, not forces! So we already deal with mechanics "based more on energy than on force"! So what's new here?

How far down the bottom of the barrel did the Huntsville Times had to scrap to get a 'science' news? The fact that a newspaper like this also can't tell the difference between legitimate science and shoddy science, and in the process also gives credibility to it, is clear evidence that scientific accuracy often takes a back-seat in many popular reporting. The public that reads this certainly would think this guy is as legitimate as any physicist out there giving a talk on something. Do they know if this guy has actually managed to publish any of his work in a peer-reviewed journal, something that is required to be considered as legimate? Or do they even care?

This is another example of "Imagination without knowledge is Ignorance waiting to happen". Except that in this cse, it has happened.


Friday, July 11, 2008

Decoders Take a Crack at Letter Sent to Fermilab

What an odd thing to gain this much traction, but then again, anything is possible on the 'net nowadays.

It appears that the very mysterious letter that was sent to Fermilab about a month ago has cause many exciting times for codebreakers everywhere.

On May 15, Jackson's group released the letter on a physics blog they had launched recently, under the heading, "Code crackers wanted!" Within a day the blog post attracted 30,000 visitors, many drawn by a link from the technology news site Slashdot, self-described as "news for nerds.


More Bad Usage Of Physics Terminology

I mentioned earlier about the media's abuse (misuse?) of the phrase "rate of speed". They mean one thing, but the words/phrase they actually used means something else. Well, here's another one.

This gem comes to use from, of all places, the New York Times editorial column, no less! It was an article written about the oil rush in Iraq. You can read the content for yourself since it isn't relevant to the issue. But read the very last paragraph of the editorial.

The United States and the oil companies must encourage Iraqi officials to make the political compromises needed to establish in law the rules for managing Iraq’s abundant natural resources with as much transparency as possible. Otherwise, oil will just become one more centripetal force pulling the country apart.

"Centripetal force" doesn't normally pull things apart. If anything, it pulls things INWARDS, together. Centripetal force provided by gravity is what keeps satellites and planets in orbit rather than flying apart. It is a "central force", acting inwards towards a force center.

What they meant in this article is "centrifugal force", which is a "fictitious" force. It is the result of being in a non-inertial reference frame and experiencing a body's tendency to maintain its inertia. Thus, in a circular motion, if you sit on the body that is moving in that circular motion, you feel an outward "force" pulling you out.

So ironically, if they had used the common centriFUGAL force as the analogy in this article, I wouldn't have paid that much attention to it, because while it isn't really a real force, the analogy is, nevertheless, accurate. But using centriPETAL force in this context is definitely not if they intended to make that point of things being pulled "apart".

Zz. {Going off to nitpick some other issues}

Thursday, July 10, 2008

ARPES Studies of the Many-Body Effects in the Electronic Structure of High-Tc Cuprates

I've posted a while back a couple of review articles on the use of angle-resolved photoemission spectroscopy (ARPES) in the study of high-Tc superconductors. In fact, one can get many interesting effects, such as the "kinks" seen in the band structure derived from ARPES experiments.

My opinion has always been that for someone who wants to study a particular field, one should always start with such review papers, or, even better, use someone's Ph.D thesis! A thesis tends to have more detailed discussion of the physics, and everything that's involved in the research, such as the experimental equipment. Luckily, we have one such example here involving ARPES. This is a Ph.D thesis written by Dmytro Inosov of IFW, Dresden in Germany which studies the many-body effects in high-Tc superconductors observed from ARPES measurements.

He has very good coverage of the basics of many-body physics, ARPES, and BCS superconductivity. One can see, for example, how the electronic band structure changes as one goes from the simple one-body non-interacting scenario to weak-coupling, to Fermi Liquid, to strongly-interacting systems. There are clear diagrams that illustrate the deviation from non-interacting systems better than I had done in my "kink" blog entry.

So if you have an inclination to study ARPES/many-body physics/superconductivity, you can't do worse than reading this thesis.


Wednesday, July 09, 2008

Popcorn Cellphone Hoax Revealed

For those who somehow bought into the video of cellphone signals popping popcorn, you ought to feel rather foolish by now. It has been revealed that it IS viral marketing by Cardo Systems.

Will these people who vehemently argued that this is possible ever learned, or better yet, learn a bit of physics? I doubt it.


Susskind Quashes Hawking in Quarrel over Quantum Quandary

California Literary Review has a rather interesting interview with Leonard Susskind on his argument with Stephen Hawking over the nature of "information" and how it is lost (or not) when it enters a black hole. This debate was highlighted in Susskind's book "The Black Hole War: My Battle with Stephen Hawking to Make the World Safe for Quantum Mechanics", which was the main reason for the CLR interview with Susskind, I would think.

I think the whole issue can be summed up in this particular question and answer.

Why was this so important?

Well it’s probably not important for curing cancer, or knocking down enemy missiles, or speeding up your computer. But it is important to the future of physics and cosmology. The universe is controlled by two fundamental laws: Einstein’s gravity theory (the General Theory of Relativity) and Quantum Mechanics. Stephen argued very convincingly that the two (GTR and QM) were on a collision course. Gravity and Quantum Mechanics were just plain incompatible. One or the other would have to give, at least by Hawking’s logic.

Stephen was wrong, but his astonishing question has changed the history of physics, and there is much more to come.

Yup! There's definitely more to come...


Tuesday, July 08, 2008

Do Cosmic Rays Get Bogged Down in the Cosmos?

A new report out of the Auger Observatory collaboration seems to indicate the presence of the GZK cutoff (link requires free registration to Physics World website) that was earlier claimed by the the HiRes observatory.

Physicists are closer to understanding how ultrahigh-energy cosmic rays make their way to Earth thanks to new measurements made at the Pierre Auger Observatory in Argentina. The study shows that the number of such cosmic rays reaching Earth drops off rapidly for rays with energies of more than about 4 x 10^19 eV.

The observations are consistent with a 40-year-old theory that ultrahigh-energy cosmic rays cannot travel very far through the universe without losing energy as they scatter off the cosmic microwave background.

4 x 10^19 eV... hum.. quick! How many orders of magnitude is that higher than the highest energy the LHC can ever reach?! And people are rabidly worried about the LHC creating blackholes?


Glut of Iron-Arsenide Superconductor Papers

Whoa! I looked at the ArXiv this morning in the Condensed Matter section and saw a glut of preprints on this iron-arsenide-based superconductors. The first 4 preprints, and 8 of the first 20 listed, are all on it.

This is as good as any of an indicator that this compound is the hottest thing to hit this field since MgB2 revealed itself to be a superconductor several years ago.


Monday, July 07, 2008

Ambitious 1.9 Billion UK Science Funding Programme is Announced

We now have a bit more detailed (and links) to the recent announcement of the UK science funding by the Science and Technology Facilities Council (STFC).

The funding includes support to universities and research facilities for fundamental science, research facilities and technology development in nuclear physics, particle physics, neutrino science, neutron scattering, lasers and light sources, space exploration and astronomy.

Highlights include support for UK participation in global astronomy projects, particle physics experiments at CERN, a neutrino physics project in Japan, a nuclear physics facility in Germany, the search for gravitational waves and exploring whether life has ever been present on Mars.

Still no "highlights" on whether they're coming back to the ILC.


Sunday, July 06, 2008

Hawk-Eye Ball Tracking

Being a tennis nut, I was obviously glued to the TV whenever I can during major tennis tournament, such as Wimbledon that has been going on the past 2 weeks. The most significant progress in tennis during the past couple of years has been the more rapid introduction of the Hawk-Eye system into various tournaments, including Wimbledon. This is the ball-tracking system that can "replay" where the tennis ball lands on the court in case there is a disputed call.

Now, what is interesting is that it doesn't involve the actual picture of a ball landing on the court. Rather, it is more complicated than that. It takes a series of video frames of the trajectory of the ball and then calculates where it will land on the court. So it isn't a direct picture of where there ball lands, but rather, using mechanics, calculate where it would have landed. Of course, the factors involved in producing such calculation is a bit more complicated since a number of parameters must be considered.

Tests have always been conducted outdoors, encompassing situations that take the following factors into consideration:

* Wind (and therefore camera wobble);
* Bright sunlight at different times of the day;
* Shadows covering part or the majority of the court;
* Dark or overcast conditions;
* Artifical floodlights.

Still, considering how winds can be swirling in different directions, and how many of these tennis balls are hit with a variety of spins, one would tend to wonder if some of the very, very close calls (ball landing 1/4 inch on the line, etc.) are valid. The problem with this is that there isn't any kind of documentation of the degree of accuracy of its call. Where are the "error bars"?

Still, I suppose it is better than the human judgment call, especially on the very close one. At the very least, it stopped the players from arguing with the umpire. Would have been interesting to see how this would have changed how John McEnroe behaved on the courts if it had been around back then. :)


Saturday, July 05, 2008

Home Photovoltaic Systems for Physicists

Just in time for $150 per barrel oil, this is a fun and timely article by Tom Murphy in this month's issue of Physics Today. It deals with the setting up of a modest photovoltaic system to run a suite of appliances. But what is interesting is that it deals with it from the background of what a physicist know. We are not electrical engineers, and while we do know the physics of semiconductor, the practical aspect of setting up something that needs to work at this level isn't trivial.

It was with those concerns in mind that I decided to explore the practical side of photovoltaic energy: In 2007 I built a PV system to power my living room. Though reasonably well informed on the semiconductor physics of PV junctions, I felt unsuitably prepared to evaluate the practical realities of owning and operating a personal solar PV system. Because I believe physicists can play a role in our energy future that extends beyond the confines of advanced research, I want to share my experiences in the hope that others might develop home PV projects. What better way to motivate innovation in the alternative-energy sector than to get a talented pool of physicists engaged on a personal level?

A recommended reading if you don't get a subscription to Physics Today.


A Quiet Revolution in SEM

This is a good review of the current advancement in Scanning Electron Microscopy (SEM) technology.

However, there has been a quiet revolution in the world of the SEM, and slowly but surely, its capabilities are expanding. The instrument can now be used to study the surface of just about any bulk material at nanometre resolution and regardless of whether it is clean or dirty, wet or dry, hot or cold, conducting or insulating. Under the most favourable conditions, sub-nanometre resolution has been achieved — especially for thin specimens imaged in transmission mode.

If you're like me and have made frequent use of a SEM facility, you'll appreciate what this workhorse can do in a pinch.


Friday, July 04, 2008

More Verification of Einstein's General Relativity

The more they test it, the more it is verified.

For the past 4 years, an international team has been carefully tracking the signals of one of the pulsars and monitoring the signals' direction during eclipses--a observational technique "that has never been employed before," says astrophysicist and co-author Rene Breton of McGill University in Montreal, Canada. The researchers determined that the precession of the pulsar's orbital axis advances by 4.77 degrees per year, plus or minus 0.66 degrees. Calculations based on Einstein's theory predicted it should advance by 5.07 degrees per year, well within the margin of error.


US Presidential Candidates Receive Questions on Science

The two US Presidential candidates received 14 questions related to science and science policy/funding.

According the ScienceDebate website, the 14 questions are designed to be “broad enough to allow wide variations in response, but specific enough to help guide the discussion towards many of the largest and unresolved challenges currently facing the US.”

You can read the actual wording of all of the 14 questions here.

Let's see if they have the courage to actually answer these questions AND also participate in the Science Debate. But based on previous attempts at having one, I'm not that confident. Even answers to these questions may not say much, since science funding is nowhere near the top of the priority for most people. Just look at the current election campaign and see if this has ever been mentioned. What we had instead are issues of "faith".


Winners and Losers in UK Funding

This could possibly stir another round of unhappiness with the physics funding in the United Kingdom.

The body overseeing UK astronomy and physics says some of its programmes will be cut back to save £81m by 2011.

Areas that will lose money are those deemed to be a low priority in a recent programmatic review.

They include support for the Integral space telescope and the Veritas observatory, both of which are concerned with the investigation of gamma-ray light; and Bison, an observatory network pursuing solar-terrestrial physics.

No word in this news report if funding is going to be restored to the UK's involvement in Gemini and the International Linear Collider, both of which they pulled out of during this last budget debacle.


Thursday, July 03, 2008

Communicating With Your PhD Supervisor

In Chapter X of my "So You Want To Be A Physicist" essay, I mentioned the process of selecting your research adviser/supervisor for your graduate work. This is possibly the most important person in your academic life and selecting someone compatible is an extremely important aspect of your education.

In last week's Science, there's a wonderful essay on the same issue that focuses on your interaction with your PhD supervisor. It deals with communicating with your supervisor no matter what style he/she adopts. This is very important especially if your supervisor is a well-known scientist that is in very high demand. So this is definitely a useful essay if you are about or just starting your graduate program.


Wednesday, July 02, 2008

High-Tc Superconductors Are Very Kinky - Update 2

A new update to my first essay on the kink feature in the ARPES spectra of high-Tc superconductors. This time, it could throw a major wrench into the analysis done previously on this high-energy kink feature that has been seen around 500 meV. The new paper[1] disputes the idea that this high energy kink is intrinsic to the band dispersion of the material. Rather, they argued that it is an artifact of the momentum distribution curve (MDC) method. Their analysis of the energy distribution cureve (EDC) does not show the same effect for that energy range.

It would be interesting to see if the previous authors who have done the analysis on this high energy kink would respond to this paper.


[1] W. Zhang et al., Phys. Rev. lett. v.101, p.017002 (2008).

Science and Maths Exams are Harder Than Arts Subjects, Say Researchers

Oooh.. now this is bound to stir up a whole bunch of hornet's nests.

Researchers at Durham University in the UK think they have evidence that shows that science and math subjects are harder than arts subjects such as English, social studies, etc. They used the grading scale in the UK's A-Level examinations as their data.

They analysed the GCSE and A-level results of almost a million students who sat exams in the summer of 2006, comparing marks in traditional sciences and maths with those in arts and humanities.

There were "substantial differences in the average grades achieved by the same or comparable candidates", they found.

A-levels in physics, chemistry and biology were marked a grade lower than A-levels in drama, sociology and media studies and three-quarters of a grade harder than English, religious education and business studies, the researchers said.

Examiners were half a grade more generous when marking students of the same ability in psychology A-level, compared with biology A-level.

For many of us, this isn't really that surprising. There have been plenty of anecdotal studies on a general consensus that the science subjects are more "difficult" both in high school and in college. However, there hasn't been any kind of systematic studies on this. Furthermore, I don't know if it is a fair comparison between the two, and certainly it is comparing apples and oranges.

Still, with the UK system, it may reinforce the fact that teachers or even parents may encourage students to take the easier subjects in their A-level exams, which may explain why the number of students in the UK taking the more difficult subjects has been declining for the past several years.


Tuesday, July 01, 2008

Supplemental Spending Bill Signed

The President signed the $186 billion supplemental spending bill which includes $338 million for science agencies in the US. Quick! What percentage of the total supplemental bill is that?! The majority of the money in the bill goes to you-know-where.

This is only a stop-gap measures that will prevent further layoffs at Fermilab and SLAC. The inherent problem not only in the budget, but in the fundamental philosophy of those in Congress hasn't changed. So there really isn't that many reasons to be optimistic at all.

Michael Lubell, a physicist at the City College of New York and APS director of public affairs, also points out that three key issues that physicists raised last December with budget makers remain “largely unaddressed”. These are cuts in funding for particle physics, the lack of support for national facilities, and the damage to America’s credibility as an international partner because of the decision to cut funds for ITER.

“Unless these issues are addressed some time in the next six months, the country will pay a heavy penalty,” said Lubell, who plans to continue lobbying over the 2009 budget.