Monday, October 31, 2011

LHC Concludes Sucessful 2011 Run

The LHC has successfully concluded its 2011 run. "Successful", you ask? They didn't find the Higgs! But that is besides the point. As far as the machine's and beam's performance go, it was extremely successful. The LHC is giving physicists everything they need, and more, in terms of luminosity and, consequently, data.

At the beginning of the year’s run, the objective for the LHC was to deliver a quantity of data known to physicists as one inverse femtobarn during the course of 2011. The first inverse femtobarn came on 17 June, setting the experiments up well for the major physics conferences of the summer and requiring the 2011 data objective to be revised upwards to five inverse femtobarns. That milestone was passed by 18 October, with the grand total for the year being almost six inverse femtobarns delivered to each of the two general-purpose experiments ATLAS and CMS.

“At the end of this year’s proton running, the LHC is reaching cruising speed,” said CERN’s Director for Accelerators and Technology, Steve Myers. “To put things in context, the present data production rate is a factor of 4 million higher than in the first run in 2010 and a factor of 30 higher than at the beginning of 2011.”
There is a greater reality that the Higgs may not be found. Certainly, it may not be found where we think it should be. This will make for a very interesting physics. While it isn't too much of a stretch to come up with a Higgless model for our elementary particles, there is also a nagging suspicions that even for such Higgless models, we should have started seeing signs of something else. And maybe we have, but that remains to be looked at in the humongous amount of data accumulated so far. There's still the 2012 run, and then eventually, a major shut down for an extended period of time to replace all those electrical issues that caused the earlier "disaster". Maybe when it gets to a significantly higher energy, we will get a clearer picture. But at this point, we don't have a clear picture on a lot of things.


Point-Contact Tunneling Spectroscopy

I came across this and said "Whoa! A major deja vu moment!"

This is a very nice paper on the principle of tunneling, and its use in tunneling spectroscopy that gives us quite a bit of information on the properties of a conventional superconductor. It describes an experiment for an undergraduate laboratory exercise. I had a deja vu moment because my PhD research was in tunneling spectroscopy using such point-contact method, but done on high-Tc superconductors which, at that time, was a "hot" commodity. I think we were one of the first groups that got a very clear V-shaped gap structure that was consistent with the d-wave symmetry.

In any case, this is a good paper to read if you want to learn an experimental technique, and certainly a good introduction to what we can learn by using such tunneling phenomenon. Of course, if you want to learn quite a bit more, than you have to read the same text that I used when I was a struggling graduate student - Wolf's standard text "Principle of Electron Tunneling Spectroscopy", which I think is still the bible for electron tunneling studies in solids.

This is also a very good opportunity to emphasize, especially those who are outside physics, of another example where a quantum phenomenon (tunneling) that is so well-known, that we are using it to study other things, in this case, the properties of a superconductor. While many may think that these quantum phenomena are nothing more than some esoteric properties that have no bearing on reality, the truth is that we make use of many of them, often to understand the stuff that we use everyday!

BTW, these undergraduate labs are getting to be more and more advanced. We already have an undergraduate experiment that showed the particle nature of light with a which-way-type experiment.


Sunday, October 30, 2011

Physics PhDs: Skills Used and Satisfaction With Employment

The AIP has released the latest set of statistics on the nature of skills used and job satisfaction for new Physics PhDs in the US from the class of 2007 and 2008.

There's not a whole lot of surprises here. You can see the type of "Scientific and Technical skills" and "Interpersonal skills" that most of these graduates found to be useful. So if you think that you should be left alone and not have to deal with people, then going into physics is not such a good idea.


Friday, October 28, 2011

"Pair Creation Constrains Superluminal Neutrino Propagation"

I mentioned a while back of the most credible challenge to the OPERA result coming from ICARUS. ICARUS made use of the theoretical calculation of the superluminal neutrino energy spectrum that was proposed by Cohen and Glashow, as mentioned in the article reported earlier.

The Cohen and Glashow paper has now been promptly published in PRL, in case anyone is interested in the citation.


OPERA Encore

Hey, did you like my play on words? Cute, no? Oh well, I can always try....

It seems that CERN has started sending beams with different pulse time structure to OPERA during the past few days. This will enable OPERA to "redo" their infamous experiment and allows them to double check a number of things to either shore up their results, or to find possible sources of errors and uncertainties in their earlier measurements.

Dr Bertolucci, the director of research at Cern, told BBC News: "In the last few days we have started to send a different time structure of the beam to Gran Sasso.

"This will allow Opera to repeat the measurement, removing some of the possible systematics."
This is one of a crucial "assumption" of the experiment, that the neutrino pulse structure is the same as the proton pulse structure. Without a near detector (which is available for MINOS), they have to assume that the same pulse structure as the proton beam propagates all the way to Gran Sasso. It would be interesting to see if a different proton beam will show itself in the neutrino pulse.

It shouldn't take very long before we get initial results out of this one, one would think. It might even be ahead of all the other tests being done at MINOS and T2K.


Thursday, October 27, 2011

Communicating Science Through Arts?

I've seen many of these attempts, and I have tried to hold my judgement on the effectiveness of such a thing, but really, I think someone should explain to me why this is a good idea.

This news items reports a seminar to be given on the topic of science and the arts. My guess is that the primary aim of this is to present science through the arts, either with painting, performance, etc.. etc. I don't get it. I've mentioned this before many times where I questioned the accuracy and effectiveness of such a presentation (read here, here, and here).

Maybe I am illiterate in the arts, but I thought that 'arts' are often subjective, and deal predominantly with emotional quality. How is this a reflection of what science is? Furthermore, how do you know how your "art" is  interpreted by the viewing public? After all, we already have seen how the public can misinterpret even when given a direct, English-language response. Interpreting it via some artistic expression will just makes it even worse, won't it?

I'm all for communicating science to the public in ways that can engage their attention and interests. I just don't think this is one of those ways, because I see it creating more confusion and misinterpretation than necessary.


Wednesday, October 26, 2011

Busting Myths to Learn Physics

Now this is one interesting way to not only teach physics, but also get students to do experimental work!

An instructor in Hamline University in Minnesota is making his first year students to a Mythbuster-type experiments to either confirm or debunk popular myths. In the process, they not only learn about the physics involved, but also learn how to properly do experiments to get reliable answers.

Physics Prof. Andy Rundquist gets the students access to the building materials and ballfields they need to answer life's pressing questions: Will tin foil scramble a speed radar? Can you climb out of a sandpit after being buried to the neck? Will a frozen golf ball fly farther?

The myths must involve physics and no strange materials. "He put the kibosh on a bunch of ideas," reported Summer Haag, a first-year student from Rochester. For example, he nixed the question of whether a duck's quack would echo. "We weren't allowed to get a duck," she said.
This is a terrific idea, and certainly is a heck of a lot more interesting than simply repeating the same experiments year in, year out. I don't know whether it will fulfill the basic syllabus for an intro physics class. I certainly think that something similar to this can be incorporated even in a standard set of the  usual undergrad physics experiments now and then, to keep things interesting. I think any experiment in which the students have to design their own set of methods to solve a problem is extremely useful.


Tuesday, October 25, 2011

Brian Greene's 'The Fabric of the Cosmos'

For better or for worse, a 4-part PBS TV series on Brian Greene's "The Fabric of the Cosmos" will air this November (at least in the US). Just barely 8 years after his series on String Theory "The Elegant Universe" aired, we will have another trip down the super-fantastic lane of speculation beyond experiment.

Don't get me wrong, I think TV series like this spurs the imagination of kids, and maybe even make them interested in physics. But I think there is a severe imbalance in areas of physics that get the publicity almost all the time, while the workhorse of physics, which occupies the MAJORITY of the subject area, does not get any type of publicity. Why? Because areas such as condensed matter seem to not be sexy enough to inspire such fantastic imagination, which is purely baloney.

So what we end up with is the impression on the public that physics is nothing more than these esoteric subject matter that has very little to do with their everyday existence. This gets very tiring very quickly.


Monday, October 24, 2011

Follow-Up To Brian Cox and Jeff Forshaw Q&A

As a follow-up to the wonderful Q&A with Brian Cox and Jeff Forshaw, we now have an audio recording that focused on quantum mechanics specifically which, I'm guessing, was recently broadcasted on the BBC.

While I don't think quantum mechanics is THAT easy to comprehend, unlike what was stated in the interview, I do think it is important that it is presented early on in school. This is because familiarity with it, and how we think about the world, makes it more easily accepted and less 'strange'. I certainly share their views of what science is, and how, by its nature, it is a continuing progression of our understanding.

A good interview to listen to.


Random Physics Picture

Inside the window on the 6-way cross is a molybdenum plug. The left, flat surface of the plug is the newly-deposited cesium telluride photocathode. This plug will be transferred, under ultrahigh vacuum, to an accelerator photoinjector, where it will become the source of electrons for a research linear accelerator. The "spring" that you can see imbedded around the plug is to enhance electrical contact of the plug to the wall of the photoinjector.


Sunday, October 23, 2011

Q&A With Brian Cox and Jeff Forshaw

This article started with the news of a new book written by Brian Cox and Jeff Forshaw. However, what I find a lot more interesting is the Q&A they had in the article that directly answers many of the most common questions that we get, especially from the general public. It is worthwhile to read these Q&A. I'm hesitant to copy the entire Q&A and post it here due to possible copyright issues, but I'm also afraid that after some time, you might not be able to read the article at the link.

So, hoping that the Guardian will understand that this is entirely for educational and informational purposes, I will copy and paste the Q&A, and full credit and copyright of this article belongs to the Guardian.


Is there a centre of the universe?
Marjorie Ainsworth, via email
JF: It's a common misunderstanding of the big bang that the universe exploded into something, like a firework went off or something like that, and there was a centre that spewed out into something.
BC: That seems to imply that everything is flying away from us and we're therefore somehow in a privileged position; that isn't true. The way it's often described is if you imagine some bread with raisins in it that you're baking in the oven and as you heat it, it expands. On any particular raisin, if you look, you can see all the other raisins receding from it. So it's space that stretching, it's not that everything's flying away.
JF: It's the big stretch, not the big bang.

If everything came from a singularity, what created it?
bbmatt, via web
JF: What created the singularity? No idea. But that doesn't mean that some people haven't tried to come up with ideas. Anyway, everything coming from a singularity is a confusing line of questioning because the universe was probably infinite at the time of the big bang so it didn't really come from a singularity. It came from a singularity in the density, but I expect that the person who's asked that question imagined that the universe came from a point.
… but that's very unlikely. We don't know what happens deep inside a black hole, so when the density of the universe gets very, very large then our calculations cease to work, so the honest answer is that before we reach the singularity, our ability to calculate fails. But that's not to undermine how accurately we can calculate, because we claim to understand the behaviour of the entire visible universe winding back through the big bang to a time when it was the size of a beach ball. So that's all the billions of galaxies and all the billions of stars in the galaxies compressed to about the size of a beach ball, which is pretty impressive.
BC: General relativity, quantum mechanics, those things break down in there, so the idea that there is such a thing as a singularity in nature is unlikely. A lot of people think that if you have a proper theory of gravity that works smaller than the beach ball metaphor then you don't have these issues, but it's not known.
JF: Another misunderstanding, which stems from that question, is the idea that the universe was small at the big bang. What was small at the time of the big bang was the entire visible universe, so everything we can see now, which is about 14bn light years away, all of that was compressed to the size of a pinhead. But it was one pinhead in an infinite space, so there's an infinite amount of stuff, as far as we can tell, outside our universe. So it's right to say that it's 14bn years old, but it's wrong to say that it's 14bn light years in size because it's probably infinitely big.
However, the question that's probably been asked is what happened before the beginning and the answer to that is that nobody has a clue – so that's the honest answer.

If there exists some particle that can travel faster than light, then surely there should be a way of sending information into the past?
jamma88 via web
BC: Yes, that's true. If you don't modify Einstein's theory of relativity and you take it at face value and send something faster than light, then yes, you can send messages into the past. So, if the current result is shown to be correct, then probably what you're saying is that you want a new theory of space and time, and then, who knows?
JF: In a nutshell, if Einstein is right, then yes is the answer to the question. But you'd be very hard pressed to find a physicist who thought that Einstein is right if you find a particle travelling faster than the speed of light. What that means is that Einstein is wrong because you can't travel back into the past and so there's some new theory that comes into play, which protects the law of cause and effect. It's very hard to conceive of a logical universe in which cause and effect doesn't hold.

What does no Higgs mean for physics? What are the other theories?
Jason Mickler via email
JF: No Higgs would be very exciting.
BC: It could be more exciting than finding it. The favoured candidate for the something new that we know must exist at the Large Hadron Collider is the Higgs, but it could be something else.
We've written several papers together and our most cited one is what would happen if there isn't a Higgs particle at the Large Hadron Collider and how we might explore the physics that must be there if there isn't one. It's very rare that you get to build an experiment in science where you're guaranteed to discover something new. The Large Hadron Collider is such an experiment, in that the standard model of particle physics predicts that there's going to be a Higgs particle. But it's not necessarily going to be there and if you take away the Higgs particle out of our standard theory, you take away all the maths and throw it in the bin and see what's left… and what's left is a theory that doesn't make sense.
JF: Something will show up sooner rather than later. If the Higgs particle is relatively light, there's a range of masses we expect it to have and we should see it very soon, we could even see it before Christmas. If it's heavy or if the alternative to it is heavy, then it could take a few more years before we find it. We're closing in on it fast now though – the machine is working absolutely wonderfully, it really is.

How do you feel about scientists who blog their research rather than waiting to publish their final results?
Stephen Marks via email
BC: The peer review process works and I'm an enormous supporter of it. If you try to circumvent the process, that's a recipe for disaster. Often, it's based on a suspicion of the scientific community and the scientific method. They often see themselves as the hero outside of science, cutting through the jungle of bureaucracy. That's nonsense: science is a very open pursuit, but peer review is there to ensure some kind of minimal standard of professionalism.
JF: I think it's unfair for people to blog. People have overstepped the mark and leaked results, and that's just not fair on their collaborators who are working to get the result into a publishable form.

Scientists use supernova explosions to measure how far away supernovas are. The distance depends on how bright they appear against how bright they really are. How do scientists know how bright the supernova explosions should be?
Bas Bouma via email
JF: When stars explode in a particular way (called Type Ia supernovae) they do so in a remarkably consistent manner – that is to say one such explosion looks pretty much the same as any other. That means that if we can measure the distance to a "nearby" supernova using some other method (and not its brightness) then we can use that to calibrate things and determine the distance to more distant supernovae using only their brightness. Incidentally, these supernovae are remarkable events. White dwarf stars are small dead stars and they survive purely as a consequence of quantum mechanics but only if they weigh less than 1.4 times the mass of the Sun. If this thing accretes matter and sneaks past the magic 1.4 solar masses then the electrons within the star start to move close to the speed of light and that triggers a catastrophic collapse – the supernova.

If question-asking is so fundamental to science, why has there been no research into how we might improve question-asking for learners in our places of education?
Laurence Smith via email
BC: I think, for example, quantum mechanics should be taught in schools for this reason. One of the reasons is that it's a great way of seeing how the data from experiments can drive you to a rather counterintuitive picture of the world. For example, the rules of quantum physics are not by themselves complicated, but they are philosophically challenging. I think the scientific method is more important to teach than facts. I'm not that bothered if people know about the structure of the atom or whatever but I want people to understand how you get to these conclusions about the world.


My question is: I cannot perceive or understand infinity. For man, everything has a beginning and an end. Answer, please!
Harry, via web
JF: The reality is that we don't know for certain what's outside the 14 billion years' worth of what we can see, so there could be an edge to the universe, it's possible, but there's no evidence in any of the data.
BC: The universe was opaque about 380,000 years after the big bang and at that point became diffuse enough that light could travel through it. And we can see that light, people measure it in great detail, and you could see if the universe had an edge in that data, but there's no sign of it.

The physics behind the current understanding of the universe isn't complete, but do you think that a new kind of mathematics will be needed, and what kind of mathematics might that be?
John Read, via email
JF: There isn't a Nobel prize for mathematics, its equivalent is called the Fields Medal and people who are working on fundamental questions in physics, string theory in particular, have won that prize in recent times, so it already is the case that physicists are breaking new ground within mathematics. People are trying to understand the universe at its birth – the behaviour of phenomena down to mind-bogglingly small scales – we're talking like 10-40cm. So new mathematics may well be needed and people are inventing new mathematics.
But it should be stressed that the known physics, the physics that we've measured in experiments, none of that really has mandated in any particularly significant way our theories of mathematics. There are exceptions, such as the idea that numbers have the property of commutativity, which means that 2x3 is equal to 3x2, but the theory of elementary particles used, for example, at the Large Hadron Collider utilises a mathematics where in the product of two numbers the order matters, so X times Y doesn't equal Y times X.


How do we know what shape the Milky Way is? I've seen many illustrations of our galaxy as a spiral, but how can we tell what it looks like when we're deeply embedded inside it?
Chris Muggleton, via email
JF: If you lived in an omelette, and you lived on the edge of that omelette, you could measure the distance between all the pieces of mushroom in the omelette. If you were clever enough to work out how far it was to all the different parts of the omelette, you'd be able to reconstruct it. So it's all a question of measuring the distance between the stars. Because they don't move any significant distance in the time you're measuring them [relatively speaking], to get the shape of it, all you need to know is the distance.

How do you feel about amateur astronomers, in today's hi-tech society?
Duncan Jones, via email
JF: Years ago, amateurs played a big part in the understanding of the cosmos, with observations and the recording of events. Unfortunately, with the advent of modern technology, the role of the amateur has been left far behind.
BC: In things such as astronomy, there's always been a place for amateur observers because there's a lot of sky. Certainly in searching for things such as new comets, they do make a contribution.
In particle physics, it's impossible for amateurs to be involved in the data because there's too much infrastructure required. In theoretical physics, Jeff might want to comment, and in theory the amateur could make a contribution because you don't have to be an academic to submit to a academic journal. If the paper makes sense then it can be published.
JF: I get a lot of papers sent to me by amateur scientists. But they've usually not got the scientific background or the training to make a contribution in theoretical physics, so it's very hard unless you've got that training.

Politics and economics

How likely is it that we'll be able to harness fusion power before we run out of fossil fuels?
@craighitchings via Twitter
BC: If we were to invest in it properly, then I'd say very likely, because the technology has been proved. In fact, the most effective fusion reactor at the moment is still in Oxford, which is where it's been for more than 30 years – and it works.
The problem is that it's not a very good commercial option at the moment because no one's demonstrated that you can build a commercially viable reactor. That's why government money has always been needed – because it's a 20- to 30-year investment. That's not the way you do things in private companies but governments can certainly help; we're talking single-figure billions, not going to the moon. So in my view, the technology has been demonstrated and it's simply a question of working out how to build industrial-scale plants that can return profit.
The real problem is that you have to contain plasma that's at a very high temperature – dismembered gas, basically. So it's very difficult to model and there are real engineering challenges. We need to understand what happens to this plasma.

Is the €75bn spent on the Large Hadron Collider worth the investment?
Oliver Gerrard via email
BC: The UK spends about £70m a year on the LHC. We spend less in Britain each year on Cern than we do on peanuts, literally, so it's a very tiny amount of money. A lot of that money funds PhD students and a lot of it pays for academics in universities – the bulk of the money actually stays in Britain. So breaking it down, it costs very little.
The other thing to understand is that the LHC is often portrayed as the search for another esoteric particle and that's nonsense. It's been built to solve a specific problem in our understanding of three of the four forces of nature. And there are all sorts of theories about how that might work, the Higgs being one of them. To portray it as some kind of esoteric hunt for an elusive particle is nonsense: it's the mainline of physics, which has arguably created wealth beyond anyone's wildest dreams and will continue to do so.

Can science save the economy?
Andrea via email
Both: Yes!
BC: It's the foundation of the economy for a start, so it'll have to! Nothing else will save it. The modern world is based on science, so that's it – there is nothing else.
JF: Yes, I'd be that definitive. For example, a significant fraction of the global economy relies upon the existence of a transistor – the world has been revolutionised by fundamental research into quantum physics done 60 years ago and now there are billions of transistors inside very home computer. They are a key ingredient of the microchip.
BC: It's science and engineering, you've got to put them together. Science and engineering together are the economy. Earlier this month, George Osborne announced the funding for science projects, including £50m for research into graphene, a material that has the potential to revolutionise the 21st century. More powerful electronics, stronger aeroplanes… pretty much anything you can think of, graphene can improve.
We are one of the world's leading scientific nations and it's my view that we should aspire to be the best.
Actually, George Osborne and this government are beginning to show signs of believing that. I think a lot of credit goes to the science minister, David Willetts, for making his point over and over again. I think it's beginning to bear fruit and we're starting to invest even at this difficult time – in fact especially at this difficult time, as that's what you need to do.

Saturday, October 22, 2011

A Lifeline for Supersymmetry?

"The report on my demise has been exaggerated"

I suppose that could be the tag line for those who are in the Supersymmetry camp after the latest news out of the CMS detector at the LHC. After a summer of discontent and the possibility that supersymmetry could be in trouble due to lack of evidence coming out of the LHC, the latest result out of CMS is throwing a lifeline on the possibility that there are hints of excessive leptons being created out of the proton-proton collisions, something that could be an outcome of a supersymmetry prediction.

The most familiar lepton is the humble electron, though other, more exotic particles such as muons and taus also fall in this category. Producing a single one of these subatomic particles in the proton-proton collisions at the LHC is relatively rare, and generating two or even three at a time is even more unusual. Certain interactions predicted under supersymmetry could enhance the odds of triple lepton events, so seeing excesses is reason to raise some eyebrows.

Yet searching for triplets of leptons is a complex task. As with many results from the LHC, the finding is subtle and could potentially be overturned with further data. Therefore, the CMS team is cautious, stressing that all their observed data is consistent with background expectations and that there isn’t definitive proof of new physics yet.
As with anything coming out of such an experiment, we just cannot jump to any kind of conclusions at this moment (remember that anomalous bump in the CDF data?). We can only read the report, sit back, and let the process of verification does its job. But at the very least, there is a faint hope for supersymmetry, for now.


Friday, October 21, 2011

Let's Make Oobleck!

Ooooh.. green goo!

Those wacky people at Jefferson Lab are at it again. This time, they are making "Oobleck"!


Thursday, October 20, 2011

Strange Bedfellows - String Theory and Condensed Matter Physics?

We have heard of this. Some aspects of the mathematics of string theory somehow have analogous form in other fields, such as condensed matter physics.

This Nature article (link may be open for free only for a limited time) explores how concepts in String Theory are now being explored in other fields, and whether this is a symbiotic relationship between them.

Sceptics still question whether this strange alliance will actually lead to new insights, or whether it is just a marriage of convenience. String theory does hint at the existence of many new states of matter, for example. But those predictions will be difficult to verify, and decisive experimental tests are only now in the planning stages.
The condensed-matter partnership seemed perfect for that. If nothing else, it promised to make a virtue out of string theory's embarrassment of riches — the roughly 10500 solutions to its basic equations, each of which describes a possible universe with its own size, shape, dimensionality and physical laws. Through Maldacena's idea, says string theorist Jerome Gauntlett at Imperial College London, "each solution can be expressed in the countless materials yet to be discovered".

The rewards are mutual, says Zaanen. "If I talk about superconductors and black holes in a colloquium, folk are attracted to it like bees to honey," he says. "It's now bringing young blood to condensed-matter physics, as their first choice."
Just as with the fictional odd couple, however, this partnership still has plenty of friction. Everyone agrees, for example, that condensed-matter physicists are much more hesitant about pairing up than their string-theory counterparts. "I have been remarkably unsuccessful at getting condensed-matter physicists to let string theorists speak at their big meetings," says Zaanen. "They fear that they will need to learn string theory to talk to them. It's as though I am asking them to have coffee with aliens."

Polchinski admits that the condensed-matter sceptics have a point. "I don't think that string theorists have yet come up with anything that condensed-matter theorists don't already know," he says. The quantitative results tend to be re-derivations of answers that condensed-matter theorists had already calculated using more mundane methods.
I suppose only time will tell if these collaborations will amount to anything. There are certainly hints at systems in condensed matter that can exhibit such rich variety of physics, such as topological insulators. Whether insights from String Theory can be beneficial remain to be seen.

Still, I don't think any of these "applications" of String theory actually validates the theory in itself. As the end of the article stated, String theory could be the "new calculus", but this is simply indicating that String theory is nothing more than a "tool", the way mathematics is, and not physics.


Wednesday, October 19, 2011

More Levitation Tricks With The Meissner Effect

This video has been getting a lot of attention, and rightly so, because they are showing magnetic levitation, but in new ways. We have seen many of these demos using high-Tc superconductors before, but these people are certainly showing it in ways that are quite unique, fascinating, and entertaining.


Tuesday, October 18, 2011

Most Credible Challenge To The OPERA Result

It's been only a few weeks, and while there have been dozens of papers either making use of the OPERA superluminal neutrino results (silly, foolish people), or trying to debunk that result. There have been many explanations offered on how the OPERA results might have been the result of an error here or there. However, I think this is the most serious and strongest challenge to the OPERA results so far, because it came from another experiment sitting quite close to OPERA at Gran Sasso, and using the same neutrino source from CERN.

The results came from ICARUS, and they looked at what is essentially the "dispersion" of the neutrino energies via looking at the dispersion of the created muons in a "neutral-currents weak-interaction" radiation. Tommaso Dorigo has a wonderful explanation for this whole process which you should read.

Essentially, what ICARUS found is that the muon spectrum is very much similar to what is expected for neutrinos moving at c, not at the speed that OPERA claimed.

They find that the energy spectrum of the detected neutrino interactions in ICARUS shows a very nice agreement with the expectation for well-behaved light-speed-moving neutrinos. A very dramatic distortion of that spectrum would instead be expected for the speed measured by OPERA, such that indeed ICARUS can place a very tight constraint on the superluminal speed of the CERN neutrinos: consistent with the speed of light, and not larger than that by more than four part in ten billionths. An order of magnitude looser than the limit obtained with the neutrinos from SN1987a, but still quite tight -and certainly excluding without argument the value of 50 millionths measured by OPERA.

If you are unfamiliar with millionths and billionths, I can make it easier for you: the ICARUS result says that the difference between the speed of neutrinos and the speed of light cannot be as large as that seen by OPERA, and is certainly smaller than that by three orders of magnitude, and compatible with zero.
The preprint on the ICARUS result can be found here. I'm sure there will be other experiments to be conducted that will try to verify the OPERA results, but this one certainly doesn't look good for OPERA.


Monday, October 17, 2011

The Neutrino Song

Holy crap! This is awful! I'm sorry I read this blog at PhysicsWorld and clicked on the link to listen to this tune. I suffered tremendously due to listening to it, so why shouldn't I subject you to the same torture? Here it is!

Now don't kill me. I'm only the messenger.

After listening to that one, the Fast Food Song doesn't sound so bad anymore!



Saturday, October 15, 2011

John Van Vleck

In my continuing effort to highlight the invaluable contribution to physics from physicists who are not household names, I would like to present, this time, the body of work done by John Van Vleck. This article is based on the symposium on his life during the last APS March Meeting this year.

What I found was fascinating was how the lives of 3 major physics figures intertwined through their parents.

The title of Charles Slichter’s lecture was “Remembering Van: Three Madison Families and other Tales.” In it, he spoke about the influential roles played at the University of Wisconsin by his grandfather, Charles S. Slichter, and the fathers of John Bardeen and John Van Vleck. The tale begins in 1903 when Charles Van Hise, a distinguished geologist, was named President of the University of Wisconsin. In 1904, Van Hise recruited Charles Bardeen, John’s father, to found a medical school at the University. In 1906, Van Hise appointed Slichter to head the mathematics department. Slichter’s first action as department head was to recruit Edward B. Van Vleck to bring strength in pure mathematics. John Bardeen and John Van Vleck did their undergraduate work at Wisconsin, finishing in 1920 and 1926, respectively. After Bardeen finished his Master’s in engineering, Van Vleck provided guidance and help, recommending him to Trinity College, Cambridge University for a fellowship and later to Harvard University for appointment as a Junior Fellow. Charles Slichter, who did his undergraduate work at Harvard, had Van Vleck as an advisor. Van Vleck recommended he remain at the university for his Ph. D. and later suggested that he do his doctoral research on magnetic resonance with Edward Purcell.
This goes to show that, while a lot of our success certainly depends on our own effort, how other things influenced our lives are certainly a matter of chance and serendipity.

And a brief "disclaimer", I am an alumnus of the University of Wisconsin-Madison, and I continue to be amazed at how many important, historical figures in physics had passed through the same hallways that I had walked through many years ago.


Wednesday, October 12, 2011

Physics And Creationism

When I read the title of the article "What Physics Teaches Us About Creationism", I will freely admit that I was all set to dislike it based on what I thought it was going to lead to, which is a justification of creationism based on the bastardization of physics. Instead, what I read was an opinion that mirrors what I had already written.

This writer made several pointed argument against creationism, and supporters of creationism, who want to teach it as an "alternative" to evolution. In this case, he was using the example of the OPERA result to falsify this often-made claim against science.

Creationists regularly assert that science is a closed operation, that those offering opinions differing from the norm cannot get a fair hearing within the scientific community. They argue that it is impossible to publish papers in the technical literature that call the dominant paradigm into question. It is this narrow-mindedness, they continue, that keeps their "important" ideas from being shared broadly. I can't begin to count the number of notes I've received from creationists who rail against the biologists who refuse to consider what they have to say. The charge is always the same: scientists are biased and unwilling to consider any ideas that contradict their opinions.

The work arising from CERN demonstrates just how absurd this argument is. The scientists responsible for the work calling special relativity into question had absolutely no trouble getting their results in front of their peers. No one closed ranks and black-listed those who challenged the prevailing paradigm. Quite the opposite occurred. The physics community is abuzz with the results, and healthy discussion, meaningful skepticism, and plans for replication abound.
I had made practically the same argument before, especially in addressing what many crackpots have always made when their "theory" got debunked.  There have been many instances in physics where the strongly-held ideas at that time had to be revamped to make way for new and better/more accurate description of our world. So people who continue to make such arguments are utterly ignorant, and hope that those who hear their arguments are also utterly ignorant of such facts.

The other argument made is the fact that creationism/intelligent design offers zero experimental data and physical evidence in its support.

Creationists, on the other hand, simply make assertions. They offer no data and perform no experiments. As was pointed out by creationists themselves under oath in the Dover, PA intelligent design trial in 2005, no one is performing any scientific investigations of intelligent design. No one is publishing any empirical data on the subject. No one is doing anything at all other than saying, "wow, it seems really unlikely and counter-intuitive for evolution to work." What the creationists want is for an alternative theory of evolution to be accepted - and taught to our children - simply because they don't like the one that currently is supported by the data and by virtually every scientist in the field.
I think this is very important, and it also separates science from many other subjects, especially the standard, typically political banter where data seldom get cited, but personal preferences are used as valid justification for something. Don't believe me? Pay close and critical attention to any political speeches and debates. See how many times the superficial claims and assertions are given the support of actual data.

There's a lot to be learn from science, not the least of which is the methodology on how we arrive at a conclusion or knowledge. I can only wish other areas and most people make the same critical evaluation of what they accept as being valid.


Tuesday, October 11, 2011

SuperB Officially Launches

While the US shuttered the last of it is particle collider experiment last month, elsewhere in the world, new particle collider experiments are either being planned, or just starting to be built. This is true in the case of the Italians and the SuperB project.

The accelerator will be what physicists call a B-factory, where electrons and their antiparticles, positrons, will race around two 1.3-kilometre-long rings, then collide and produce heavy B mesons. By studying the way these particles decay, physicists hope to fill some of the gaps in the standard model of physics, such as why there is more matter than antimatter in the Universe, and whether the exotic particles predicted by the theory of supersymmetry really exist.

SuperB will produce 100 times more collision events each year than did the two B factories previously built: the BaBar experiment at the SLAC National Accelerator Laboratory in Menlo Park, California, which shut down in April 2008, and the ongoing Belle experiment at the KEKB accelerator in Tsukuba, Japan. This increased luminosity should allow researchers to study even the rarest of physical phenomena.
Coupled that with the planned upgrade to Belle II at Japan's KEK, high energy physics experiments are slowly but surely migrating outside of the US. There's not a whole lot to be proud of here if you are concerned about high energy physics in the US.


Feynman - The New Hero

It appears that Richard Feynman is the new hero of a graphic novel (cartoon?). His life story seems to have been turned into a series of graphic sketches in this new book.

In “Feynman,” read about how the irrepressible and colorfully sketched PhD pulls pranks on his fellow researchers on the Manhattan Project. Watch as the rascally professor solves the Dirac Equation. Observe as the hard-partying genius boldly calls Niels Bohr by his given name, instead of by his code handle “Nicholas Baker.” In one panel of the 300-page book, Feynman spins dinner plates to unlock secrets of quantum mechanics; in another he humiliates a NASA official during the Rogers Commission investigation of the Challenger explosion.
I suppose this man will remain popular to the public in general because of his "quirkiness".


Monday, October 10, 2011

LHC@Home Attracts Large Support

I mentioned this a while back. It appears that a lot of people are eager to participate in the distributive computing effort to do a lot of simulations for the LHC. Since its announcement, the LHC@Home has received a lot of support.

The application Test4Theory, which runs Monte Carlo simulations of events in the LHC, was announced in a CERN press release on 8 August. Within three days, the number of registered volunteers swelled from a few hundred to nearly 8000.

Certainly nothing to sneeze at. Still, they're expecting 40,000 participants in this project, and that will result in an interesting consequence:

According to CERN's Peter Skands, the physicist leading the simulation effort, when the number of active volunteers passes 40,000 – which could happen later this year – the system will become equivalent to a true "virtual collider", producing as many collisions per second as the real LHC.
Fire away!


2010 Nobel Lectures

A year after the date that they were announced as Nobel Prize winners in Physics, the Nobel lectures given by K. S. Novoselov and Andre K. Geim have now been published in Rev. Mod. Phys. They are "free to read" articles.


The Physics of Flying Pumpkins

Each year, during this time of the year in the US, many pumpkins are scarified in the name of physics! :)

This is another example of a physics high school teacher trying to demonstrate Newtonian mechanics by shooting pumpkins.

“The students got a lot out of the project, but they're not done yet,” said physics teacher Jeff Partynski. “They must now analyze the flight of their pumpkins and create a detailed report that includes calculations, design criteria, and results.”

Partynski requires students to build catapults that can shoot pumpkins at least 20 meters.

The project requires the application of principles like projectile motion, energy, and forces. They also learn to work in teams like engineers or scientists tasked with at corporations.
Too bad they weren't shooting at some structure with round, green heads strategically placed in it...... Hum... OK, maybe I've been playing Angry Birds way too much.


Sunday, October 09, 2011

Tenson Within OPERA

I heard about this uneasiness within the OPERA collaboration since the news broke, but I didn't think it was appropriate to pass on rumors such as that. But now, with the news being reported on PhysicsWorld, it is now official that there are large section of the collaboration that want to make sure things are double-checked and looked into again before even submitting it for peer-reviewed publication.

The announcement made headlines around the world, since it appears to contradict Einstein's special theory of relativity. However, not everyone within OPERA was happy to release the results publicly, with several of the 30 group leaders within the 160-strong collaboration being opposed to the release of a paper on the arXiv preprint server and the accompanying seminars and press release without further tests of possible systematic errors being carried out. Now, a larger fraction of the group leaders is concerned about the paper being submitted to a research journal. One member of OPERA, who does not wish to be named, says there is a "lot of tension" within the collaboration and that up to half of the members are opposed to an immediate submission.
This article pointed out two possible issues with the OPERA analysis, and these are the two issues that have bothered many who have read the preprint.

One such check regards the timing of the neutrinos' arrival at Gran Sasso, and involves carrying out an analysis of timing data collected by monitoring the charge, rather than the light, generated by particles passing through the detector. This analysis relies on a very precise and painstaking measurement of the length of the cabling used to collect the timing data, in order to isolate any systematic errors that may be present within the electronics or other parts of the timing system.

Another independent check involves the statistical analysis of the data collected by OPERA. The researchers are not able to track, and therefore time, individual neutrinos as they travel from Geneva to Gran Sasso, but instead they measure the temporal distribution of the protons within each bunch just before the protons hit the graphite target and then compare this with the distribution of the corresponding neutrinos as they are detected in OPERA – with the temporal offset between the two revealing the time of flight. Some members of the collaboration argue that this offsetting procedure needs to be carried out independently, in order to be sure that the temporal profile of the neutrinos leaving CERN can be inferred accurately from that of the protons that produced them.
That last part could be crucial. They were using the proton temporal distribution to be the same as the neutrino temporal distribution. Unlike MINOS, OPERA has no Near Detector to verify the neutrino temporal distribution before they travel all that distance to Gran Sasso. MINOS, on the other hand, has a near detector right at Fermilab, with the Far Detector located hundreds of miles away in Soudan, Minnesota. In some sense, I think it will be up to MINOS, and to some extent, T2K, to verify this result, which they will be able to do within a year.

So sit tight. The next few months will be very interesting.


Thursday, October 06, 2011

Saul Perlmutter Nobel Prize Press Conference

Video of Saul Perlmutter Nobel Prize Press Conference.


How to Land Jobs Outside Academia

This panel discussion for students and postdoc was held as SLAC. It consisted of members who are physicists and working outside of academia. In essence, this panel discussion tries to impart on how one gets a job, what should one do to be well-prepared for such a career, and how to go about applying/seeking such a job.

If you have been a long-time reader of this blog, you would notice similarities between what was said here, and what I've been saying all along. For example:

It’s never too early to start, added Chris Barnes (Stanford, ’07, and SLAC), and late of Solyndra. “The time to acquire the specific skills is when you’re still in school and can take classes,” he said. Some of the panelists focused on programming skills as a good example, but Exploratorium Senior Scientist Paul Doherty (MIT, ’74), said it never hurts to expand your physics problem-solving repertoire, as well.
I've always tried to emphasize this. In my "So You Want To Be A Physicist" essay, I explicitly said so in "Part VIII: Alternative Careers for a Physics Graduate"

If you have followed the series so far, you would have noticed that very early on, I emphasized one very important thing: the acquiring of a range of skills during your undergraduate years. This includes everything from computer programming skills to experimental skills. This is extremely important for any students, but especially if you end your physics education upon completion of your undergraduate degree. If you decide to pursue employment, your employability depends very much of what you can do. Let’s face it, not many employers are looking for someone who can ”do physics”. There are, however, employers who would like someone who can analyze numerical models and maybe write codes, or maybe someone who can work in an electronics industry doing thin film fabrication, etc. You will be surprised that some of the things you accidentally picked up in an advanced physics lab might be the very thing that gets you the job.
I repeated this theme in my idealized letter to the student "So I Am Your Academic Advisor"

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


Wednesday, October 05, 2011

"Vision to reality: From Robert R. Wilson's frontier to Leon M. Lederman's Fermilab"

Now that the Tevatron has become part of our history, it is an appropriate time to look back at the history of Fermilab, and how it became what it is (was?). This article does that by examining the era under two different Fermilab administrations, that of Robert Wilson, and subsequently that of Leon Lederman.

Abstract: This paper examines the roles of vision and leadership in creating and directing Fermi National Accelerator Laboratory from the late 1960s through the 1980s. The story divides into two administrations having different problems and accomplishments, that of Robert R. Wilson (1967-1978), which saw the transformation from cornfield to frontier physics facility, and that of Leon Max Lederman (1979-1989), in which the laboratory evolved into one of the world's major high-energy facilities. Lederman's pragmatic vision of a user-based experimental community helped him to convert the pioneering facility that Wilson had built frugally into a laboratory with a stable scientific, cultural, and funding environment.  

Ref: Phys.Perspect. 5 (2004) 67-86.


Producing X-rays At The APS

One of the most common misconception that I have to deal with is the idea that light can ONLY be created upon an atomic transition. You wouldn't believe how many people believe that this is the only way to create light. This shows a severe lack of understanding of classical E&M and Maxwell equations.

The one example that I typically use to counter such misconception is to tell people to figure out how synchrotron centers around the world create light, or EM radiation. In particular, many of these centers generate x-rays to be used for various purposes. These x-rays are generated via "charge acceleration", either by using the bending magnet, or using the insertion devices that essentially cause the electrons to "jiggle" up and down (or sideways) as if they are at the end of a spring. These cause the generation of EM radiation. No "atomic transition" is involved.

This video shows clearly how x-rays are produced at the Advanced Photon Source at Argonne National Lab.


Tuesday, October 04, 2011

"It Wasn't IKEA!"

Adam Rees had the best reaction to the phone call from the Swedish Academy informing him of his Nobel Prize in Physics this morning.

Riess said his "jaw dropped" when he received an early-morning call at his home in Baltimore from a bunch of Swedish men and realized "it wasn't Ikea," the Swedish furniture retailer. "I'm dazed," he told AP.
I had quite a good chuckle after reading that! :)


Liquid Nitrogen Vs. Liquid Oxygen

This fun and crazy folks at JLab are at it again. This time, they teach you the difference between liquid nitrogen and liquid oxygen, using a flame!

They are just plain hilarious!


Nobel Prize Awarded For Dark Energy

The Nobel Prize in Physics this year was awarded to the 3 main figures in the discovery of Dark Energy. Half of the award is given to Saul Perlmutter of LBNL. The other half is given to Brian Schmidt of Australian National University and Adam Riess of Johns Hopkins.

This is a rather bold and brave move. While dark energy is considered to be "mainstream" in cosmology, its acceptance is still debatable in many circles, and certainly to the MOND folks. The Nobel prize tends to be more conservative, awarding it to people who has discovered something that is well-documented. Dark energy is still a phenomenon that we are still trying to pin down, as evident by many new efforts, such as DES, etc. that are about to go on line. So it is certainly a bold more (unprecedented?) to award for a discovery that has a degree of certainty that many considers to not be as high as other previous Nobel prize winning discovery..... YET.

And oh, Reuters-Thompson's prediction is wrong again! :)


Monday, October 03, 2011

You Can Do It, But Did You Understand It?

Chatting with a bunch of people about our times in college brought up something that had crossed my mind a few times. Was there a course or subject area in which you could pass or get through, or even got good grades in it, but you thought that you didn't actually had a good grasp on it?

I certainly did. And the subject area was Thermodynamics. For some odd reason, even though I got good grades in it, I just didn't think I actually GET IT when I was an undergraduate. At that time, I thought that the subject was disjointed, and I see a lot of "starting points", where such-and-such an equation or description goes with such-and-such a problem. I didn't see any underlying uniform idea through the whole thing. Yet, I could still do well in exams.

I didn't get that feeling in other subjects, such as Classical Mechanics, E&M, QM, etc. I'm not saying that I find those easy, or easier, but at least I had a clear "view" of the material and able to figure out where I was at any given time. In Thermo, I had a pieces of the puzzle, and I can work with that puzzle, but I never had a clear idea of the whole picture.

That, of course, changed very quickly in graduate school where I finally had to 'apply' stuff that I learned in Thermo, and finally, many parts of it started to sink in. Now, I think, if I were to retake my undergraduate class in that subject, I can see the bigger  picture that applies to that particular problem or area. But I found it rather strange and disconcerting that I didn't have that level of understanding at that time.

I'm guessing that this is not unusual, and that a lot of students, especially in the intro physics courses, are able to get through by simply knowing how to work out a problem, rather than having a profound understanding of what they are dealing with.