Wendy Science

Every year I get asked to write letters for the evaluation of faculty at other institutions for tenure and/or promotion. My typical thought process on being asked to write a letter for someone I don't know well is: "OK, I've heard of that person/read their papers/seen them at conferences. Sure, I'll write a letter." Then I note the due date and send off a quick e-mail agreeing to write the letter. Most often the request arrives in the summer and I write the letters in summer or early fall. [If you click on the 'tenure' label in the frame on the right -- perhaps after scrolling down a bit -- you will see my previous comments on writing tenure letters.] When it gets to be time to study in detail the materials relevant to the evaluation -- for example: CV, selected publications -- in many recent cases I have dealt with (recent = past 5 years) -- there have been complications. Example complications: unexplained gaps in the publication record (at least, unexpla...

We also deal with elementary stuff here. The people at the Frostbite Theater at JLab has another video out. This time, they show an experiment on which pipes heats the most when shined with light. The results is not surprising. But what is surprising is why the white pipe heats up faster initially. So, anyone wants to enter a Science Fair to study why this is so, especially when Steve is way too old to enter? Zz.

Not sure how long this article will be available without a subscription, but in case you missed this article on LIGO in last week's issue of Nature, this is a good one to keep. De Rosa, a physicist at Louisiana State University in Baton Rouge, knows he has a long night ahead of him. He and half a dozen other scientists and engineers are trying to achieve 'full lock' on a major upgrade to the detector — to gain complete control over the infrared laser beams that race up and down two 4-kilometre tunnels at the heart of the facility. By precisely controlling the path of the lasers and measuring their journey in exquisite detail, the LIGO team hopes to observe the distinctive oscillations produced by a passing gravitational wave: a subtle ripple in space-time predicted nearly a century ago by Albert Einstein, but never observed directly. It's a daunting task, with instrument of such precision, that so many things can contribute to the "noise" being detected. We w...

The news about the x-ray emission line seen in the Perseus cluster that can't be explained (yet) by current physics. The preprint that this video is based on can be found here . Zz.

A new experimental result has confirmed quantitatively the presence of a quantum critical point . The researchers experimentally confirmed the predicted linear evolution of the gap with the magnetic field, which allowed them to pinpoint the location of the quantum critical point. At the critical field, the observable is expected to display a power-law temperature dependence, another hallmark of quantum criticality, with a characteristic power of - 3 / 4 in this case—precisely what they observed. Even more, a rigorous experimental analysis allowed them to estimate the prefactor to this behavior, which they found to correspond nicely to the theoretically predicted one. And finally, they observed this behavior to persist to as high a temperature as almost half of the exchange coupling, which sets the global energy scale of the problem. This answers an essential question about how far away from the absolute zero temperature quantum criticality reaches or how measurable it really is. The...

Student comments on my teaching of a particular course: Great professor! I have enjoyed this class! I liked the readings. This course required too much previous knowledge. Professor very helpful with homework. Homework very useful for class. Well-constructed lectures. Very organized lectures. She speaks very clearly. She answered my homework questions. She provided images and charts to supplement the subject matter. The in-class exercises were helpful. I liked the practice exercises we did in groups during lecture. I liked that she asked questions during class and this helped deepen my understanding of concepts. Useful supplementary material to help us understand lecture material. She explained the topics completely in class. Didn't use a textbook as a crutch. It was great that lecture and lab material were well coordinated. She was always ready to answer questions. She was always willing to help with any questions. She provided the subject matter very clearly. The last project was...

In case you missed it and are interested in this area, this is a review article, which happens to be a chapter in a book, on " Topological Insulators, Topological Crystalline Insulators, and Topological Kondo Insulators ". This is not meant for non-experts because it reviews the current understanding of this family of material. Zz.

I initially thought that this Newsweek article was reporting something new that had been discovered in quantum mechanics that had some serious applications. But it turns out that it was more of an article that quite clearly described all the practical advances that came out of QM. At the most basic, almost everything we do is grounded in quantum physics—matter (all of it) is a collection of quantum particles, while light, electricity and magnetism are all quantum phenomena. At the next level are the quantum technologies we humans built without being aware of the physics that made them possible. When Swan and Edison produced electric lightbulbs, they didn’t know that light generated from a heated filament is a quantum process—they ended up implicitly drawing on quantum physics without even knowing it. . . . It only takes a few minutes analyzing a smartphone to realize the pervasiveness of quantum technology. To start, quantum physics is required to construct any solid-state electronics...

As a condensed matter physicist by training, the issue of charge transport in matter has always been a topic that I encounter often, especially when I was doing my postdoc many, many years ago. While the physics of charge transport in metals, under "ordinary" situations, can be adequately described by the Drude model, resulting in, for example, the beloved Ohm's Law, there are many other situations where such a simplistic model just doesn't work. And in those situations, that is where the physics gets very interesting and can be quite complicated. The factors that influences charge transport in matter depends very much on how a charge carrier scatters. So the scattering rate determines the properties of resistivity/conductivity, etc. In a metal, there several types of scattering: electron-phonon scattering, electron-impurity scattering, and electron-electron scattering.[1] The dominant term that has a strong temperature dependence is the electron-phonon scattering, wh...

The UK's Institute of Physics has awarded JILA's Deborah Jin with this years Isaac Newton Medal , which is the IoP's most prestigious award. In 1999 Jin and her then PhD student Brian DeMarco were the first researchers to cool a gas of fermionic atoms so low that the effects of quantum degeneracy could be observed. This phenomenon underpins the properties of electrons in solid materials, and the ability to create and control ultracold "Fermi gases" has since provided important insights into superconductivity and other electronic effects in materials. Working with Cindy Regal and Markus Greiner at JILA, Jin later created the first fermionic condensate in 2003, by cooling a gas of potassium atoms to nanokelvin temperatures. I've always said that she deserves a Nobel Prize in physics for this work. It is also about time that a woman wins this after several deserving ones had been overlooked. Zz.

This is the put-up-or-shut-up challenge, very much like James Randi's challenge to prove the existence of supernatural phenomenon. A physicist has put up $30,000 of his own money to challenge global-warming skeptics to unequivocally show him evidence that man-made global warming doesn't exist. Dr Keating -- a professor of physics for over 20 years and author of Undeniable: Dialogues on Global Warming -- is offering a grand prize of $30,000 of his own money to anyone who, using the scientific method, can disprove the existence of man-made climate change. In addition, he is offering a smaller prize of $1000 to anyone who can provide any valid scientific evidence against man-made climate change. You can read his official statement of the challenge on Keating's blog. Now, this is NOT to say that he is looking for proof of warming due to anthropic causes. There's a difference here. He's looking for FALSIFICATION of the claim, i.e. evidence that such a claim of human ...