Quantum Diaries

There has been a wave of advice posts recently, for new graduate students making their decisions by the April 15 deadline, and for graduating PhDs who are receiving their degrees by the end of the semester. Congratulations to both groups! What I have to say today is most relevant to first or second year students ready to make an exclusive commitment to a research group.

Last Wednesday morning my alarm went off at 4:30 so I can catch my 7:30 flight. Four phone calls, six emails and seven hours later I was back at my desk, having moved my 36 hour trip to the following day since my plane had mechanical problems. The first email I read was from the lab’s travel office, wondering if I knew that the way I have arranged my summer travel right now meant I had a round trip each to China and Japan within two weeks. “Yes,” I responded, “I planned it that way.” The trips are three days apart and it’s cheaper to fly back and forth than to book a complicated itinerary with a stopover and three unnecessary nights at a hotel. In exchange for jetlag I collect miles.

Travel is very much a fact of life in high energy physics. Most people, including myself, consider it a perk. At least most of the time. It’s an opportunity to see new places all expenses paid. But it’s not without its drawbacks, and I recommend that any grad student find out about travel and moving before they sign up for it. Some of these you can ask your future adviser directly, some you might be better off finding out through more senior grad students.

Where will you need to travel, how often, for how long? Do you have to move long term (months to years) or is it an option to live near your university and travel for shifts/meetings? This is especially important for those with significant others, families or plans to start a family. Or even pets.

Is there enough funding for all the mandatory travel? This is a good one to ask more senior grad students. You want to be able to travel to a summer school and a couple of conferences throughout your few years in addition to mandatory travel. It wouldn’t hurt to find out about the typical accommodation.

If you’re an international student and need to travel internationally – do you need a visa to travel to and from your destination? This is extremely important, since it can mean being allowed or denied reentry to the US, and very few (if any) people in your department will have reliable information on it. Talk to the equivalent of the “Office of International Students” in your university, as soon as possible. Lots of arrangements are possible, but happen on bureaucratic timescales.

Another one possibly important for international travel is dietary preferences or restrictions. I now have to travel to China frequently, and my second favorite sight, after the Forbidden City in Beijing, was shelves of Skippy peanut butter at a grocery store.

Finally, once it’s time to go, make sure you talk to those who have traveled before you about their experiences. Small things like a restaurant recommendation or advice on navigating public transportation in a language you don’t speak can make your experience significantly better. If possible for your first trip, plan your travel to coincide with someone who’s done it before.

Bon voyage!

In a new paper in Nature, IceCube shows a solid, non-detection of neutrinos from gamma-ray bursts (GRBs). That is, the expected emission of neutrinos if GRBs were the sources of the highest energy cosmic rays was not observed. There had been a generally agreed model of GRB emission, and now it’s essentially ruled out. Cosmic rays remain a mystery…

More personal comments on this in a bit, but let me send along some of the news coverage in the shorter term:

IceCube popular version of the Mystery of the Cosmic Rays

IceCube press release

“Although we have not discovered where cosmic rays come from, we have taken a major step towards ruling out one of the leading predictions,” said IceCube principal investigator and University of Wisconsin-Madison physics professor Francis Halzen.

Deux scientifiques pakistanais sont arrivés au CERN en février, au plus fort de la vague de froid. Pendant toute l’année 2012, ils vont travailler en collaboration avec les spécialistes des aimants du CERN, en s’initiant à la technologie et en prenant part aux projets en cours.

Sumera Yamin, physicienne, et Khalid Mansoor Hassan, ingénieur électricien, sont deux scientifiques du Centre national de physique d’Islamabad venus travailler au CERN dans le cadre d’un accord avec le Pakistan.

«Ils se sont immédiatement mis à l’œuvre en nous aidant à concevoir et à assembler de nouveaux aimants pour l’expérience ALPHA, explique Davide Tommasini, chef de la section responsable des aimants résistifs. Ils se sont tout de suite adaptés, comme je l’espérais. C’est incroyable de constater que tous les scientifiques ont la même approche.»

Les deux nouveaux venus participeront également à certaines étapes de la conception d’aimants et aux spécifications techniques du projet SESAME (Centre international de rayonnement synchrotron pour les sciences expérimentales et appliquées au Moyen-Orient), le premier centre de recherche d’envergure internationale de la région.

Sumera Yamin (à gauche) et Khalid Mansoor Hassan (à droite) avec un aimant quadripôle dans une des zones expérimentale du CERN.

SESAME a été fondé sous les auspices de l’UNESCO en prenant le CERN pour modèle. Il compte actuellement parmi ses membres le Bahreïn, Chypre, l’Égypte, l’Iran, Israël, la Jordanie, le Pakistan, l’autorité palestinienne et la Turquie. Le but est de d’établir des ponts au niveau culturel et scientifique entre des sociétés diverses et contribuer à une culture de paix à travers une coopération internationale en science. Le projet vise aussi à prévenir et même renverser la fuite actuelle des cerveaux en établissant un centre de recherches de pointe en sciences des matériaux, physique, chimie et sciences de la vie.

Le CERN soutient cette initiative en partageant son expertise, notamment en ce qui concerne le système d’aimants. En 2010, les directeurs du CERN et de SESAME ont signé un protocole de coopération. Les spécialistes du CERN pourront également former le personnel de SESAME si ce dernier en fait la demande.

Le Pakistan est membre de SESAME et participe également à la collaboration CMS au CERN. Il souhaite aider le CERN à promouvoir le projet SESAME et, dans le même temps, acquérir une expertise dans la science, la technologie et la conception des accélérateurs pour développer ses capacités nationales.

La construction du bâtiment principal de SESAME, à Allan, en Jordanie, a été achevée en 2008. D’ici à 2015, ce centre de recherche commencera à accueillir des utilisateurs et utilisatrices originaires de l’ensemble de ses États membres et leur permettra de venir pour de courtes périodes afin de réaliser des expériences particulières, avant de retourner dans leur pays pour procéder à l’analyse des données. Le but est de créer un environnement scientifique stimulant qui encouragera les meilleur-e-s scientifiques et technologues de la région à y rester, voire même y revenir.

Les deux scientifiques s’attèlent donc à la tâche d’apprendre tout le processus de la construction des aimants pour l’anneau principal de SESAME. Ils travaillent en ce moment sur la conception et les spécifications devront être finalisées pour la fin du printemps. Le but est de pouvoir construire et/ou assembler la plupart des composantes au Moyen Orient. En même temps, le Pakistan mise sur des scientifiques comme Sumera et Khalid pour acquérir une expertise en technologie des accélérateurs et développer ses propres applications dans le domaine médical.

«Nous bénéficions de l’aide et de l’attention de l’ensemble du groupe, assure Khalid. Dès que nous soulevons une question, quelqu’un propose de prendre un café pour en discuter!»

Mais ces conversations autour d’un café ne sont pas la seule expérience qu’ils retiendront de leur séjour au CERN. «C’est un apprentissage différent, ajoute Sumera, plus participatif, plus ouvert.» Sumera et Khalid apprécient l’environnement multiculturel du CERN, et c’est avec plaisir qu’ils s’imprègnent au quotidien de nouvelles connaissances.

Pauline Gagnon

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Two Pakistani scientists arrived at CERN in the midst of the cold snap in early February. They will spend the coming year working in collaboration with CERN’s magnet experts both learning the technology and contributing to ongoing projects

Sumera Yamin, a physicist, and Khalid Mansoor Hassan, an electrical engineer, both from the National Centre for Physics in Islamabad, came to CERN thanks to an agreement with Pakistan.

“They started contributing right away, helping us build new magnets for the ALPHA experiment,” says Davide Tommasini, Head of the resistive magnet section. “They fitted right in, just like I had expected. It is amazing to see that all scientists share the same approach.”

The two scientists will also contribute to some aspects of the magnet design and technical specifications for the SESAME project, the Synchrotron-light for Experimental Science and Applications in the Middle East, the first major international research centre in the making for the region.

Sumera Yamin (left) and Khalid Mansoor Hassan (right) next to a quadripole magnet in one of CERN test areas.

SESAME was set up on CERN model and likewise, it is being developed under the auspices of UNESCO. Its current members are: Bahrain, Cyprus, Egypt, Iran, Israel, Jordan, Pakistan, Palestinian Authority and Turkey. The goal is to build scientific and cultural bridges between diverse societies, and contribute to a culture of peace through international cooperation in science. It also aims at preventing or even reversing brain drain by enabling world-class scientific research in basic properties of materials science, physics, chemistry, and life sciences.

CERN is supporting this initiative by sharing its expertise in particular for the magnet system. In 2010, CERN and SESAME Directors signed a collaboration protocol. CERN’s experts will also deliver training to SESAME personnel on request.

Pakistan is both a member of SESAME and the CMS collaboration. Its goal is to support CERN in its effort in favor of SESAME, and, by the same token, build expertise in accelerator science, technology and design for domestic use.

SESAME main building was completed in Allan, Jordan in 2008. By 2015, this research center will start welcoming scientists from all member states. As a “user facility”, scientists will come for short visits, perform a specific experiment and return home for the data analysis. The goal is to create a motivating scientific environment that will encourage the region’s best scientists and technologists to stay in the area or to return if they have left.

The two scientists are now hard at work learning how to build magnets from scratch for the SESAME main ring. They are working on the design and the specifications should be finalized by late spring. The goal is to have most components produced and/or assembled in the Middle East. In parallel, Pakistan counts on scientists like Sumera and Khalid to build expertise in accelerator technology and develop its own skills for medical applications.

“We are getting a lot of help and attention from the whole group”, says Khalid. “Every time we need to discuss something, someone proposes we go for coffee!” But discussing everything and nothing over coffee is not the only memory they will have of CERN. “This is a very different learning experience,” adds Sumera, “more cooperative, more open”. Both Sumera and Khalid enjoy the multicultural environment and are happily soaking up all the new knowledge.

Pauline Gagnon

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I don’t know the original source, but there’s an image that has gone semi-viral over the past year which challenges the reader to identify several brand names based on their logos versus plant names based on their leaves. (Here’s a version at Adbusters.) The point is to contrast consumerism to the outdoors-y/science-y education that kids would get if they just played outside.

This isn’t the place to discuss consumerism, but I don’t agree with idea that the ability to identify plant names carries any actual educational value. Here’s my revision to the image:

On the right we’ve encoded all of the particles in the Standard Model in a notation based on representation theory. In fact, this is almost all of the information you need to know to write down all of the Feynman rules in the Standard Model (more on this below).

Tables that the one above are a compact way to describe the particle content of a model because the information in the table specifies all of the properties of each particle. And that’s the point: whether we name a particle the “truth quark” or the “top quark” doesn’t matter—what matters is the physics behind these names, and that’s captured succinctly in the table. Science isn’t about classification, it’s about understanding. I leave you with this quote from Feynman (which you can watch in his own words here):

You can know the name of a bird in all the languages of the world, but when you’re finished, you’ll know absolutely nothing whatever about the bird… So let’s look at the bird and see what it’s doing — that’s what counts. I learned very early the difference between knowing the name of something and knowing something.

Addendum: naming those particles

For those who want to know, the particles in the table are, from top down:

1. The left-handed quark doublet, containing the left-handed up quark and left-handed down quark
2. The anti-right-handed-up quark
3. The anti-right-handed-down quark
4. The left-handed lepton doublet, containing the left-handed electron and left-handed neutrino
5. The anti-right-handed electron (a.k.a the right-handed positron)
6. The anti-right-handed neutrino
7. The Standard Model Higgs

SU(3), SU(2), and U(1) refer to the strong force, weak force, and hypercharge. Upon electroweak symmetry breaking, the weak force and hypercharge combine into electromagnetism and the heavy W and Z bosons. Here’s how to read the funny notation:

1. Under SU(3): particles with a box come in three colors (red, green, blue). Particles with a barred box come in three anti-colors (anti-red, anti-green, anti-blue). Particles with a ‘1’ are not colored.
2. Under SU(2): particles with a box have two components, an upper and a lower component. That is to say, a box means that there are actually two particles being represented. More on this below. Particles with a ‘1’ do not carry weak charge and do not talk to the W boson.
3. Under U(1): this is the “hypercharge” of the particle.
4. The electric charge of a particle is given by adding to the hypercharge +1/2 if it’s the upper component of an SU(2) box, -1/2 if it’s the lower component of an SU(2) box, or 0 if it is not an SU(2) box (just ‘1’).

As a consistency check, you can convince yourself that both the left- and right-handed neutrinos carry zero electric charge. Note, also, the fact that we’ve written out left-handed and right-handed particles differently. This is a reflection of the fact that the Standard Model is a chiral theory.

Finally, I said above that the table of particles almost specifies the structure of the Standard Model completely, the additional pieces of information required are:

1. Which of the above particles are fermions and which are scalars (the gauge bosons are implied)
2. Write down the most general ‘renormalizable’ theory (we write only the simplest interaction vertices)
3. Specify the pattern of electroweak symmetry breaking (the Higgs)
4. Specify the flavor symmetries (three of each type of matter  particle)

From this one can write the complete mathematical expressions for the Standard Model. One then just has to fill in the observed numerical values to be able to calculate concrete predictions for actual processes.

In the past I’ve made it known that I’m a politically-engaged person — and not without some commentator controversy. While I generally prefer to keep my science and politics separate, they inevitably intersect in the matter of governmental funding of scientific research and conflicts between groups driving the national dialogue on science policy. Unfortunately, scientists are often left behind in this conversation, resulting in a serious disconnect with the public.

It’s not hard to find embarrassing stories about how Americans are ignorant of basic scientific knowledge: roughly half believe dinosaurs and humans coexisted, 1 in 5 adults believes the Sun revolves around the Earth, and when it comes to acceptance of evolution, we’re out of step with much of the world. On many topical issues — global climate change, nuclear energy, genetically-modified foods, vaccination, cell phones — an abundance of misinformation drowns out the science, or at least muddies the waters. And even worse, many Americans don’t understand how scientists draw their conclusions, i.e. the scientific method, nor do they apply it in their daily lives. A much-quoted survey from 2007 found that 70% of Americans are “scientifically illiterate” (though that distinction, as well as the statistic, is misleading: scientific literacy is not on a binary scale).

I realize that I’m probably preaching to the choir here: You all have made the effort to read a physics blog written by physicists about highly technical topics, which suggests to me that you are either totally awesome science enthusiasts or… scientists. Thanks for reading! 🙂 But from whom does the rest of the country not following Quantum Diaries get its science information?

Well, for starters, there’s Hollywood and the entertainment industry, where scientists are commonly portrayed as mad/evil or awkward geniuses — people to fear or mock, perhaps, but not befriend or idolize — and scientific accuracy is typically thrown out the window in favor of more explosions. There’s also the Internet, where people can and do say pretty much whatever they want without the need for peer review or, you know, facts. Do you remember when unfounded fears that CERN was going to create an Earth-devouring black hole ricocheted around the web? Although the Internet is an incredible resource for information and personal research, it’s treacherously inconsistent. The public also learns about science from the news/media, where sensationalism is routine and “fair and balanced” reporting means giving equal time to scientific fact and wild speculation. Recently, a chemistry publication entitled “Evidence for the Likely Origin of Homochirality in Amino Acids, Sugars, and Nucleosides on Prebiotic Earth” made headlines when, in its final two sentences, the author suggests that advanced, potentially dangerous, dinosaurs could exist elsewhere in the universe. Take a guess on how the media covered it. Unfortunately, most Americans don’t learn about science from scientists, and given the abject mess of these other sources, it’s a wonder that a quarter of the population is “scientifically savvy and alert.”

Well, an explainable wonder: America is the only country in the world that requires undergraduates to take a year of general education — and it makes a difference! Education works, who would’ve guessed? 😀 However, there is serious cause for concern, particularly with regards to K-12 education. One of the great legacies of the Bush Administration, the “No Child Left Behind Act” of 2001, tied federal funding of public schools to student performance on annual, standardized tests in math and reading (laughably, the law stipulates that all children are to perform above average). Perhaps not surprisingly, educators under pressure are more likely to “teach to the test” to improve scores at the expense of other subjects and skills, such as science and critical thinking. Should we worry about what will happen when the NCLB generation makes it to Physics 101…?

It’s worth pointing out that a post-secondary education in physics, for instance, is also subject to distorted priorities: Our training is extremely focused on skills needed to continue in Academia and fundamental research, while statistics show that a significant fraction of us go on to careers in industry immediately after grad school, and that the most-used skills are not properly developed in the curriculum. Furthermore, in the long term, most of us end up working outside of Academia. Are we better off learning electrodynamics from a glorified textbook on special topics in mathematical methods? I think not.

More to come!

— Burton 🙂