The Chinese work ethic often makes an impression on foreign researchers. “It's humbling to see people working so hard,” says Tsun. He says that half the Pasteur Institute is sometimes still in the lab after 7 or 8 p.m. — something that Tsun rarely saw during his PhD research at the University of Oxford, UK.
But hard work doesn't always translate into creativity. Many of the students “haven't been trained so much in using their knowledge to generate new ideas and find new solutions”, says Danielsen. “They work extremely hard and very long hours, but I am not sure whether they are able to step back a bit and reflect on the results.” Wickham says that the science is often highly managed by professors, and researchers are not encouraged to take risks or learn from their mistakes.
Monday, January 30, 2012
Work in China looks like ......
Friday, December 16, 2011
How SSC came into being
Sunday, December 11, 2011
Back now
Wednesday, October 19, 2011
criteria for Physica B
The scope of Physica B comprises all condensed matter physics, including both experimental and theoretical work. Papers should contain a new experimental, calculated, or theoretical result of which the physics is properly discussed.
The requirement of the presence of some new condensed matter physics means that typical materials science papers which, for instance, mainly concern a new more efficient or cheaper preparation method of a material or the optimization of an already known physical property of a material with the aim of application, fall outside the scope of Physica B.
The criteria for EPL
Key features of an EPL article [https://www.epletters.net/4DCGI/_referees&ref_guide/-1/0/0/0/0/0/119557474]
The main criteria for papers to be accepted for publication in EPL are:
| Scientific soundness • a manuscript should report important results of substantial research. Unnecessary details should be avoided. Speculative ideas are discouraged, unless some physically sound argument is given in reasonable support. |
| Importance and future impact • results should be novel and of significant importance for the field to which they contribute and possibly to others. At least some indication should be given of a possible impact on the ongoing research. |
| General interest • work should be at the forefront of a field of broad interest, and the results should be put into a broader context of related work. Making them accessible to researchers in other fields of specialization may be achieved by suitable, clearly written introduction and conclusion (if appropriate). References should of course be adequate and representative. |
A letter is intended to be a communication of a new result or finding which merits rapid publication. It is not meant to be simply a short or abbreviated paper. In case a manuscript is found to be acceptable for publication as a regular article, but not as a letter, it may be suggested to the authors that submission to one of the journals that are part of the Mutual Transfer Agreement would be more appropriate.
Articles should contain a clear title, abstract and introduction, accessible to physicists outside the research area of the physics under discussion. Does the introduction explain, in terms accessible to a broad audience, the physics context of the work, why it is important and what has been accomplished? However, the main body of the article should contain enough technical information to enable peers to corroborate results and follow the details of the work described. The article should be likely to be well read and to make a real contribution to the subject area. If appropriate, a conclusion section should be included providing a non-specialist summary of the major points raised in the article, but not just a repeat of the abstract.
Report form
If possible, please indicate your assessment of the article using the boxes provided and justify/detail your choices in the text.
Key points of the referee report
Referees should address a number of key points in their assessment that relate to scientific content and quality, presentation and possible impact to the scientific research field.
Scientific content
| • | Scientific merit: Is the work scientifically rigorous, accurate and correct? |
| • | Appropriateness: Is the material appropriate for the journal? Does the work deviate too far from physics, or contain too little physics, to be considered as inter-disciplinary science publishable in this journal? |
| • | Clarity: Are ideas expressed clearly and concisely? Are the concepts understandable? Is the discussion written in a way that is easy to read and understand? |
| • | Technical: Does the article contain information not known before and how important is this to the research field in question? |
| • | Interest: Is the research presented put in context of the research field as a whole? EPL articles should be accessible to both specialist and non-specialist. |
Quality
| • | Originality: Is the work relevant and novel? Does the work contain significant additional material to that already published? Is this paper likely to be cited in future? |
| • | Motivation: Does the problem considered have a sound motivation? All papers should clearly demonstrate the scientific interest of the results. |
| • | Repetition: Have significant parts of the manuscript already been published? Does the article contain significant new material in addition to that already published? |
| • | Urgency: Articles of especially high quality or interest will be published as soon as possible and may be highlighted in promotional material. |
| • | Title: Is it adequate and appropriate for the content of the article? |
| • | Abstract: Does it contain the essential information of the article? Is it complete? Is it suitable for inclusion by itself in an abstracting service? |
| • | Introduction: Is the introduction written in an easy to follow format, with a clear, informative content for a non-specialist? |
| • | Diagrams, figures, tables and captions: Are they essential and clear? |
| • | Text and mathematics: Are they brief but still clear? Is the standard of English acceptable? |
Monday, October 3, 2011
Why bother to go that way ? No need at all
Monday, September 5, 2011
The h-index
1. The most influential journals: Impact Factor and Eigenfactor, PNAS, 106:6883
2. An index to quantify an individual’s scientific research output, PNAS, 102:16569
Sunday, August 14, 2011
The physics of how bubbles clean dusts
A team at the Nanyang Technological University in Singapore led by Claus-Dieter Ohl adapted a technique for creating a bubble where and when they wanted it. They focused a laser pulse up through a glass microscope slide into a strongly absorbing liquid dye. The laser heating caused the bottom layer of the dye to evaporate explosively, forming a hemispherical bubble at the glass surface that grew to tens of microns in radius and then collapsed, all within about 25 microseconds. The team stuck several-micron-diameter plastic beads on the slide surface and immersed them in the dye to mimic dirt particles adhering to a surface. They then recorded video of the beads' motion in response to the bubble.
Wednesday, August 3, 2011
Physics about Guinness
Look closely at a pint of Guinness and tell me: do the bubbles go up, or do the bubbles go down? Why is the head coloured the way it is? Is foam a gas, liquid or solid? An Irish physicist discusses.
....
The paper referenced in this discussion is "Waves in Guinness" by Marguerite Robinson, A. C. Fowler, A. J. Alexander, and S. B. G. O'Brien [DOI: 10.1063/1.2929369; free PDF]. And yes, it is rather intense reading, unless you are a fluid physicist or an astronomer. [http://www.guardian.co.uk/science/punctuated-equilibrium/2011/aug/02/1]
Sunday, July 31, 2011
The role of phase
What it shows: Fifteen uncoupled simple pendulums of monotonically increasing lengths dance together to produce visual traveling waves, standing waves, beating, and random motion. One might call this kinetic art and the choreography of the dance of the pendulums is stunning! Aliasing and quantum revival can also be shown.
How it works: The period of one complete cycle of the dance is 60 seconds. The length of the longest pendulum has been adjusted so that it executes 51 oscillations in this 60 second period. The length of each successive shorter pendulum is carefully adjusted so that it executes one additional oscillation in this period. Thus, the 15th pendulum (shortest) undergoes 65 oscillations. When all 15 pendulums are started together, they quickly fall out of sync—their relative phases continuously change because of their different periods of oscillation. However, after 60 seconds they will all have executed an integral number of oscillations and be back in sync again at that instant, ready to repeat the dance.
Monday, July 25, 2011
Wednesday, July 20, 2011
Theory sometimes goes ahead of experiments
Surely, a lot of theoretical scientists (e.g., Abrikosov) admit that they follow closely experiments. And they are mostly motivated by them. In numerous cases, little interest might be invested in a subject until some lab fellows could get their hands on it. Graphene offers a typical example of this kind. Before 2004, few body payed attention to this seemingly abstract material. The situation drastically changed due to Geim et al's fabrication. Often, only after the material becomes experimentally available and controllable will theorists come out to construct models and explain observations or make predictions. Efforts are primarily concentrated on such systems that already exist or at least, likely to exist. A great portion of work then surrounds the comparison between models and empirical data. This is especially true with particle physics or other arena where fundamental laws are sought. In these fields, the objects are created by GOD and already there and to be discovered.
But, in materials science or more generally, in condensed matter physics, one has to reset mind. Here, many things are invented rather than discovered. Experimentalists can be motivated by theorists, and model can advance data. Novel phases may not exist in any materials that are known currently, but in some models that are constructed merely by imagination. These models, although seem irrelevant to reality when they are born, could drive some workers to look for possibilities of realizing them in labs. On such occasions, it is not about qualifying or falsifying a theory. It is about how to put it into reality and into use. A nice example might be the spin liquid or Z2 gauge theory or string model. All these when born were nothing but brain products. But these thought products have been behind many many many wonderful experimental work.
In short, theory can go ahead. And it is not always about explanation and prediction. It can fostering new reality.
Tuesday, July 19, 2011
washboard road effects
Experimentation and analysis lead the physicists to conclude that the washboard effect is not, in fact, due to the suspension of the vehicles driving over it. As well, the size of the wheel and the size of the sand grains are irrelevant. Most surprising of all, the rotation of the wheel was also irrelevant, since the effect could be reproduced with a fixed, non-rotating object! In the end, all that mattered was the mass and velocity of the wheel, density of the road bed, and the acceleration of gravity. The fact that the velocity of the wheel was important also explains why the effect is worse on certain sections of road:
The speed of the wheel appears to be crucial. Indeed, there exists a critical velocity below which the road always remains flat and above which washboard bumps appear. Typically, for a car this critical velocity is around 5 mph or 8 km/h.
Monday, July 4, 2011
Graphene age
Tuesday, June 21, 2011
How do wings work ?
Now Bernoulli’s equation is quoted, which states that larger velocities imply lower pressures and thus a net upwards pressure force is generated. Bernoulli’s equation is often demonstrated by blowing over a piece of paper held between both hands as demonstrated in figure 2. As air is blown along the upper surface of the sheet of paper it rises and, it is said, this is because the average velocity on the upper surface is greater (caused by blowing) than on the lower surface (where the air is more
or less at rest). According to Bernoulli’s equation this should mean that the pressure must be lower above the paper, causing lift. The above explanation is extremely widespread. It can be found in many textbooks and, to my knowledge, it is also used in the RAF’s instruction manuals. The problem is that, while it does contain a grain of truth, it is incorrect in a number of key places.
What’s wrong with the ‘popular’ explanation?
The distance argument;
The ‘equal time’ argument;
The Bernoulli demonstration.
Next, examine a particle moving along a curved streamline as shown in figure 7. For simplicity we can assume that the particle’s speed is constant3. Because the particle is changing direction there must exist a centripetal force acting normal to the direction of motion. This force can only be generated by pressure differences (all other forces are ignored), which implies that the pressure on one side of the particle is greater than that on the other. In other words, if a streamline is curved, there must be a pressure gradient across the streamline, with the pressure increasing in the direction away from the centre of curvature.
Monday, June 20, 2011
Physics Education Journal
http://iopscience.iop.org/0031-9120/
Tuesday, April 26, 2011
Correction is more inadvertent than prevention: electronics
The error rate in complementary transistor circuits is suppressed exponentially in electron number, arising from an intrinsic physical implementation of fault-tolerant error correction. Contrariwise, explicit assembly of gates into the most efficient known fault-tolerant architecture is characterized by a subexponential suppression of error rate with electron number, and incurs significant overhead in wiring
and complexity.We conclude that it is more efficient to prevent logical errors with physical fault tolerance than to correct logical errors with fault-tolerant architecture.
Sunday, April 24, 2011
Suggestions from the editorial board of PR
Editorial: The Aim of a Good Introduction (October 21, 2005)
A primary goal of Physical Review Letters is to keep a broad spectrum of physicists informed about current research findings in areas outside their specializations. To accomplish this, a Letter needs clearly written introductory paragraphs that are understandable by nonexperts. Communication to a general readership is, however, an ongoing challenge for PRL editors and authors. To aid in this effort, we offer some guidelines to authors for writing the introduction:
1. The introduction should interest people outside the subfield in reading the article. Because it is directed at nonspecialists, it should have a minimum of jargon and acronyms.
2. It should describe the background and history of the problem or research goal addressed in the article. It should explain the importance of this research and of the results being reported, as well as any relevance they have to other areas of physics ("The work described here is motivated by...").
3. A well organized introduction starts with the general discussion described in point (2) and ends with a brief description of the specific results presented ("In this Letter we show..."). Discussions of technical details should be reserved for the main text.
4. In our experience, a good introduction requires a minimum of 1 double-spaced manuscript page, i.e., 32 single-column published lines, and may range up to 2 such pages, or 64 published lines.
Good writing is difficult and requires thought and effort; this is especially true when one attempts to communicate technical results to people outside the field. It would be a useful practice if, before submitting a manuscript to PRL, the authors asked colleagues in other areas to comment on its readability, with particular emphasis on the introduction. Authors who do not feel comfortable writing in English may find it helpful to consult colleagues more experienced in this regard.
[And the following are the criteria for PRL acceptance]
Acceptance Criteria
Physical Review Letters publishes Letters of not more than four journal pages and Comments of not more than one journal page. Both must meet specific standards for substance and presentation, as judged by rigorous review by editors and referees. The Physical Review and Physical Review Letters publish new physics. Thus, prior publication of the same results will preclude consideration of a later Letter. In addition, the findings must not be a marginal extension of previously published work; they must not be a repetition of prior results on a similar system, without additional physical insight.
Substance
Validity.— Work is valid if it is free of detectable error and is presented in sufficient detail that this may be determined. Papers that advance new theoretical views on fundamental principles or theories must contain convincing arguments that the new predictions and interpretations are distinct from existing knowledge and do not contradict experiment.
Importance.— Important results are those that substantially advance a field, open a significant new area of research or solve–or take a crucial step toward solving–a critical outstanding problem, and thus facilitate notable progress in an existing field. A new experimental or theoretical method may be a suitable basis for a Letter, but only if it leads to the significant advances presented above. Mathematical and computational papers that do not have application to physics are generally not suitable. Papers that describe proposed experiments must provide compelling evidence that the proposal is novel and feasible, and that it will lead to valuable new research.
Broad Interest.— Work is of broad interest if it is a major advance in a field of physics or has significant implications across subfield boundaries. A manuscript may also be of broad interest if it is exceptionally pleasing science, aesthetically.
Presentation
The diversity of the readership of Physical Review Letters places special demands on style. A Letter must begin with an introduction that states the issues it addresses and its primary achievements in language understandable across physics subfields. Each Letter should present a complete discussion within the constraints of a short communication. Letters must be clearly written, devoid of unnecessary jargon, with symbols defined, figures well drawn, and tables and figures thoroughly captioned. When appropriate, a Letter should be followed by a more extensive report in the Physical Review or elsewhere.
Importance of Introductory Paragraphs
Physical Review Letters is unique in its commitment to keep broadly interested readers well informed on vital current research in all fields of physics. This is achieved with introductory paragraphs that state, for each article, the issues addressed and the primary achievements. It is essential that these paragraphs be clearly written and comprehensible to nonexperts. To assure compliance, the referees are instructed to pay particular attention to the introductory section. In addition, the editors will make an independent evaluation of the adequacy and clarity of the introduction.
Tuesday, April 19, 2011
A big jump
Particle physicists haven't discovered anything truly surprising in 35 years, so a mere hint of something odd works them up in a hurry. So it was last week, when, aided by press reports, news spread that scientists in the United States may have spotted a bit of matter unlike any seen before. But even as they contemplate the implications, physicists are taking the result with a grain of salt. The supposed signal could be an experimental artifact, caution the researchers who found it. And if a new particle is there, physicists may have to perform theoretical contortions to explain why they didn't spot it before. “I think the result is rather inconclusive,” says Christopher Hill, an experimenter at Ohio State University in Columbus, who was not involved in the work.
The finding comes from the 700-member team working with the CDF particle detector at Fermi National Accelerator Laboratory (Fermilab) in Batavia, Illinois. The team analyzed the billions of collisions of protons and antiprotons produced by Fermilab's atom smasher, the 25-year-old Tevatron, which will shut down this year. Those high-energy collisions can blast into fleeting existence massive subatomic particles not seen in the everyday world. Physicists try to identify those particles by studying the combinations of familiar particles into which they decay.
In this case, experimenters searched for collisions that produced a particle called a W boson, which weighs about 86 times as much as a proton, along with some other particle that disintegrates into two sprays of particles called “jets.” A jet arises when a collision or decay kicks out a particle called a quark. A quark cannot exist on its own but must be bound to other quarks or an antiquark. So the energetic quark quickly rips more quarks and antiquarks out of the vacuum of empty space, and they instantaneously form particles called mesons, each containing a quark and an antiquark. From the energies and momenta of the two jets, researchers can infer the mass of the particle that produced them.
CDF researchers see about 250 events in which the jets seem to come from a particle weighing about 155 times as much as proton. Those events show up as an unexpected peak in a data plot (see diagram). The chances that random jets or jet pairs from other sources would produce a fake signal that strong are 1 in 1300, the physicists estimate. “We've been struggling for 6 months to make this peak go away, and we haven't been able to do it,” says Robert Roser, a physicist at Fermilab and co-spokesperson for the CDF team. Still, he says, the signal is “not even close” to strong enough to claim a discovery.
Experimenters have several reasons to be cautious. The analysis depends critically on physicists' understanding of jets. CDF does not measure every particle in a jet, so researchers must make a 25% upward correction to a jet's measured energy. If the uncertainty in that fudge factor is bigger than they estimate, “then maybe the excess isn't so significant,” says Shahram Rahatlou of Sapienza University of Rome.
CDF physicists must also take care that they haven't mistaken random pairs of jets for new particles. To see the peak, they must subtract out a huge “background” produced by events containing a W and random jets. If that subtraction isn't just right, it could produce a fake signal. “The real question is how well do we understand that [background],” says Joseph Lykken, a theorist at Fermilab.
But those caveats have not stopped theorists from trying to explain the curious bump in terms of new particles. Felix Yu, a theorist at the University of California, Irvine, suggests that the new particle could be one known as a Z′ (pronounced Z-prime), which would convey a new force much like a very short-range electromagnetic force. Estia Eichten, a theorist at Fermilab, and colleagues say the particle could be a “technipion,” a particle predicted by a type of theory called “technicolor,” which posits a new kind of strong nuclear force.
To have escaped notice until now, however, a particle would have to have some weird properties. Generally, a Z′ ought to decay into an electron and an antielectron. In fact, experimenters have already searched for and failed to find that decay. So Yu's Z′ must not decay that way for some reason. The technipion may face similar problems. CDF researchers are searching for the long-sought Higgs boson, the key to physicists' understanding of mass, by looking for events in which it is produced with a W boson and in which the Higgs decays into two jets specifically triggered by particles called bottom quarks. The hypothetical new particle hasn't shown up in those Higgs searches, so it must not often decay into bottom quarks, as one would expect a technipion to do.
For those reasons, some physicists say such explanations of the bump seem contrived or “unnatural.” “Yesterday, these models weren't popular,” Hill says. Yu counters that “having a theory that looks pretty but doesn't fit the data isn't natural.”
The supposed signal should be confirmed or ruled out in short order. The CDF team has analyzed only half of the data it has already collected. And the Tevatron's other large particle detector, D0, has a data set as big as CDF's. If the particle is there, D0 should see it, too. “We hope that within a few weeks you'll be hearing from us,” says Dmitri Denisov, a physicist at Fermilab and co-spokesperson for the D0 team. In the meantime, physicists will enjoy the buzz.
Monday, April 11, 2011
Q&A with Philip Philips
Phillips, whose Ph.D. is in theoretical chemistry, says he probably would not have taken such an unusual approach if his background had been more conventional. Science Careers talks to Phillips about how his circuitous route from chemistry to physics prepared him to go down this new research avenue.
The following highlights from the interview were edited for brevity and clarity.
- Q: How did you first become interested in science?
P.P.: My parents were in the humanities. I was born in Tobago, and we moved to the U.S. when I was 10. I was very interested in math as a kid. Science was interesting, but I had very bad teachers in high school and so I had no real way of knowing what science would be about.
At the university, I took a chemistry class, and that's when I really became interested in science. So I started taking many more science classes, and I realized too late that my real interest was in physics. I needed one more class for a physics major, and so I had degrees in math and chemistry.
- Q: How did you go about choosing your Ph.D. program?
P.P.: I wanted to be a theoretician because math was always my thing, and if I was going to do science, I wanted to apply math to understanding physical problems. [But] I realized, given my limited undergraduate background, that somehow being able to chart a course that was intellectually what would be my focus for the rest of my life was just not possible. So I viewed a Ph.D. as a degree in which I learned how to do research, and the particular problem wasn't something I was deeply interested in at all. My project was on explaining phosphorescence lifetimes in small molecules.
- Q: Did you get what you needed out of your Ph.D.?
P.P.: I had an adviser who was an incredibly brilliant person, and he really taught me how to get something done. He gave me this sense of just being able to take on a challenge even if you have no experience with the field.
- Q: What was your next step?
P.P.: I got a Miller Fellowship at [the University of California,] Berkeley. The key thing I got interested in was disordered systems, and I started really thinking about many-body systems and phenomena that arise from collective physics, the sorts of things that would define my career.
I just started reading all the papers, and then I defined a new problem that others had not solved that I thought would advance the field. So the problem I was working on at Berkeley was an electron moving in a random array of scatterers. I learned the necessary math tricks to be able to solve this problem, and then I started doing it. That's what I'd learned from my adviser: how to chop something down that is completely new and make progress on it.
As a Miller fellow, I was doing this on my own. It was a big jump from single-particle stuff to, essentially, statistical mechanics, and the mindset was very different. It was painful and a lot of stuff I had to learn, but it was what I knew I wanted to do.
- Q: You then obtained a faculty position at the Massachusetts Institute of Technology (MIT), in the chemistry department. What did you work on there?
P.P.: This problem led me to look at Anderson localization, which is the problem of electrons moving in a random lattice. Solids have a regular array of atoms, and what Anderson showed is that if enough of the atoms are different, the electrons change from being able to move freely to being completely stuck. In one and two dimensions, it's generally been thought that any amount of disorder would lead to localization. But we found the general exceptions. And then I showed that certain classes of conducting polymers could be explained by the examples that lead to exceptions to localization. That application was motivated entirely because I was in a chemistry department.
- Q: You then decided to move to Illinois after 9 years at MIT. Why?
P.P.: I was forced out. What I was doing had nothing to do with their definition of chemistry. Some supported me and some didn't. But even if I had gotten tenure, I would have had to move to a physics department.
- Q: Were you aware at the time that you were risking tenure?
P.P.: Yes, I was very much aware of this. You have to be honest with yourself. There were no problems in chemistry that interested me. I have always just thought that you should do what you think is important regardless of whether it might work out or regardless of whether or not your colleagues think it will work out.
- Q: You obtained tenure at the University of Illinois right away. Do you feel as though you've found your place now?
P.P.: Illinois has been absolutely a gold mine for me, yes. Personality-wise, in terms of the research I'm able to pursue here, in terms of a supportive environment, in terms of my research being central to the condensed matter effort of the department.
Credit: Rick Kubetz, University of Illinois
Philip Phillips collaborated with theoretical particle physicist Robert Leigh, also of the University of Illinois, Urbana-Champaign. Not shown in the picture and also contributors to the work are postdoctoral fellow Mohammad Edalati and graduate student Ka Wai Lo.
- Q: So what has been your focus at Illinois?
P.P.: The big problem I have been trying to solve since 1995 is the physics of strongly coupled electron systems. I have been attempting to figure out what it is that the electrons are doing as they interact with one another [within cuprate superconductors]. Our work shows that they form composites, and so once you understand what the composites are, then you can begin to describe the macroscopic properties of the system.
[In 1998, Argentinean physicist Juan] Maldacena made a conjecture in which he argued that there is a relationship between a strongly coupled quantum mechanical system and a gravitational system [that] is entirely classical Einsteinian gravity. So in fact, strongly coupled quantum mechanical systems that are charged are equivalent to a curved space-time with a black hole in it. We showed that if you just introduce some probe fermions and these probe fermions are coupled to the space-time in a particular way, that system looks identical to the normal [nonsuperconducting] state of high-temperature superconductors.
Others have used this mapping before. What we did that was new is that we used a particular interaction between the probe fermions and the black hole that is really irrelevant to the physics of the black hole but changes the physics at the boundary of the space-time [which is where the quantum mechanical theory lives]. No one suspected it.
With such a model, you can just forget about trying to figure out what the basic building blocks are, just go and solve this geometry problem and extrapolate it to what's going on at the surface of this geometry, and you'll see what the quantum mechanical system is doing.
- Q: And so have all these years of getting closer to your true scientific interests finally paid off?
P.P.: It takes a lot of daring to invest the time to go and learn this machinery [for geometrizing quantum mechanics] because it's fairly nontrivial stuff, and to think that it has answers for a real-life system is another risk.
I certainly thought that, God, if I were more traditionally trained, maybe I could have known some of the pitfalls of some of the things I've tried in the past. But now it's turning out that it was a good thing. The most important thing about my roundabout way is that I don't have any biases. I'm very open to new approaches and new problems and I don't mind just going and rolling up my sleeves and trying something new. This research is the culmination of what I thought I wanted to do when I was a graduate student.
