Tag Archives: physics

Pseudogap and Superconductivity

MIT physicists shed light on key superconductivity riddle

Hudson’s team is focusing on the state of matter that exists at temperatures just above the temperature at which materials start to superconduct. This state, known as the pseudogap, is poorly understood, but physicists have long believed that characterizing the pseudogap is important to understanding superconductivity.

In their latest work, published online on July 6 in Nature Physics, they suggest that the pseudogap is not a precursor to superconductivity, as has been theorized, but a competing state. If that is true, it could completely change the way physicists look at superconductivity, said Hudson.

“Now, if you want to explain high-temperature superconductivity and you believe the pseudogap is a precursor, you need to explain both. If it turns out that it is a competing state, you can instead focus more on superconductivity,” he said.

Magnetic Movie

Magnetic Movie from Semiconductor on Vimeo

Magnetic Movie was shot in NASA’s Space Sciences Laboratories at UC Berkeley for Chanel 4 in association with the Arts Council of England.

In Magnetic Movie, Semiconductor have taken the magnificent scientific visualisations of the sun and solar winds conducted at the Space Sciences Laboratory and Semiconducted them. Ruth Jarman and Joe Gerhardt of Semiconductor were artists-in-residence at SSL. Combining their in-house lab culture experience with formidable artistic instincts in sound, animation and programming, they have created a magnetic magnum opus in nuce, a tour de force of a massive invisible force brought down to human scale, and a “very most beautiful thing.”

Magnetic Movie is the aquavit, something not precisely scientific but grants us an uncanny experience of geophysical and cosmological forces.

Cool video: I must admit I am confused at how extensive the artistic license taken with the animation is.

Measuring Protein Bond Strength with Optical Tweezers

Using a light touch to measure protein bonds

MIT researchers have developed a novel technique to measure the strength of the bonds between two protein molecules important in cell machinery: Gently tugging them apart with light beams. “It’s really giving us a molecular-level picture of what’s going on,” said Matthew Lang, an assistant professor of biological and mechanical engineering
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The researchers studied the interactions between the proteins by pinning one actin filament to a surface and controlling the motion of the second one with a beam of light. As the researchers tug on a bead attached to the second filament, the bond mediated by the actin-binding protein eventually breaks.

With this technique, the researchers can get a precise measurement of the force holding the proteins together, which is on the order of piconewtons (10^-12 newtons).

Cloak of Silence

Experts unveil ‘cloak of silence’

“The mathematics behind cloaking has been known for several years,” said Professor John Pendry of Imperial College London, UK, an expert in cloaking. “What hasn’t been available for sound is the sort of materials you need to build a cloak out of.”
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The Spanish team who conducted the new work believe the key to a practical device are so-called “sonic crystals”. These artificial composites – also known as “meta-materials” – can be engineered to produce specific acoustical effects.
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The research builds on work by scientists from Duke University in North Carolina, US, and the Hong Kong University of Science and Technology. Earlier this year, independent teams from the two institutions demonstrated the mathematics necessary to create an acoustic cloak. Other scientists have shown that objects can be cloaked from electromagnetic radiation, such as microwaves.

Shaw Laureates 2008

Image of the Shaw Prize Medal

The Shaw Prize awards $1 million in each of 3 areas: Astronomy; Life Science and Medicine; and Mathematical Sciences. The award was established in 2002 by Run Run Shaw who was born in China and made his money in the movie industry. The prize is administered in Hong Kong and awards those “who have achieved significant breakthrough in academic and scientific research or application and whose work has resulted in a positive and profound impact on mankind.” The 2008 Shaw Laureates have been selected.

Astronomy
Professor Reinhard Genzel, Managing Director of the Max Planck Institute for Extraterrestrial Physics, in recognition of his outstanding contribution in demonstrating that the Milky Way contains a supermassive black hole at its centre.

In 1969, Donald Lynden-Bell and Martin Rees suggested that the Milky Way might contain a supermassive black hole. But evidence for such an object was lacking at the time because the centre of the Milky Way is obscured by interstellar dust, and was detected only as a relatively faint radio source. Reinhard Genzel obtained compelling evidence for this conjecture by developing state-of-the-art astronomical instruments and carrying out a persistent programme of observing our Galactic Centre for many years, which ultimately led to the discovery of a black hole with a mass a few million times that of the Sun, in the centre of the Milky Way.

Supermassive black holes are now recognized to account for the luminous sources seen at the nuclei of galaxies and to play a fundamental role in the formation of galaxies.

Mathematical Sciences
Vladimir Arnold, together with Andrei Kolmogorov and Jurgen Moser, made fundamental contributions to the study of stability in dynamical systems, exemplified by the motion of the planets round the sun. This work laid the foundation for all subsequent developments right up to the present time.

Arnold also produced extremely fruitful ideas, relating classical mechanics to questions of topology. This includes the famous Arnold Conjecture which was only recently solved.

In classical hydrodynamics the basic equations of an ideal fluid were derived by Euler in 1757 and major steps towards understanding them were taken by Helmholtz in 1858, and Kelvin in 1869. The next significant breakthrough was made by Arnold a century later and this has provided the basis for more recent work.

Ludwig Faddeev has made many important contributions to quantum physics. Together with Boris Popov he showed the right way to quantize the famous non-Abelian theory which underlies all contemporary work on sub-atomic physics. This led in particular to the work of ”²t Hooft and Veltman which was recognized by the Nobel Prize for Physics of 1999.
Continue reading →

Materials Engineers Create Perfect Light “sponge”

Materials engineers create perfect light “sponge”

The team designed and engineered a metamaterial that uses tiny geometric surface features to successfully capture the electric and magnetic properties of a microwave to the point of total absorption.

“Three things can happen to light when it hits a material,” says Boston College Physicist Willie J. Padilla. “It can be reflected, as in a mirror. It can be transmitted, as with window glass. Or it can be absorbed and turned into heat. This metamaterial has been engineered to ensure that all light is neither reflected nor transmitted, but is turned completely into heat and absorbed. It shows we can design a metamaterial so that at a specific frequency it can absorb all of the photons that fall onto its surface.”
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The metamaterial is the first to demonstrate perfect absorption and unlike conventional absorbers it is constructed solely out of metallic elements, giving the material greater flexibility for applications related to the collection and detection of light, such as imaging, says Padilla, an assistant professor of physics.

Saving Fermilab

Fermilab was once the premiere particle physics research lab. It is still a very important research lab. But, I have said before, other countries are the ones making the larger efforts lately to invest in science and technology centers of excellence that the US was making in the 1960’s and 1970’s: Economic Strength Through Technology Leadership, Investing in Technology Excellence, etc..

I have also said that the past success of the US has left it in a still very strong position. For example, the anonymous donor that saved Fermilab with a $5 million donation likely benefited from the successful investments in science centers of excellence in the past (few countries – maybe 30, can rely on large donations from wealthy individuals, to sustain centers of excellence and I don’t think any approach what the USA has now – Howard Hughes Medical Institute, Standford, MIT…).

Excellent post on the the saving of Fermilab, To the person who saved Fermilab: Thank You.:

The facility has recently seen financial difficulties which have resulted in the layoffs of research staff and dramatic cuts in experiments. The world class research facility has been left to scrape together funds to pay the bills and has even had to auction off equipment and ask staff members to take pay cuts just to keep the lights on in the laboratories.
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Fermilab also has an illustrious history of achievements in the field of supercomputer development and parallel processing. Fermilab has been on the forefront of applying supercomputing to physics research and is one of the top supercomputing centers of the world. Fermilab has claimed the world’s most powerful supercomputer on multiple occasions – although the title is rarely held long by any system due to the continuous advancements in computing. In recent years, Fermilab has been a leader in the development of “lattice” supercomputing systems and has developed methods for efficiently utilizing the power of multiple supercomputers in different locations through more [efficient] distribution practices.

To some, the construction of the Large Hadron Collider at CERN may seem to reduce the importance of Fermilab’s capabilities, but this is not at all the case. Although the LHC may take the title for the overall size and energy levels of a particle accelerator, Fermilab remains a uniquely capable particle physics research institution. Though less powerful, the Tevatron is able to operate for longer periods of time than the LHC and will likely require less downtime for maintenance, allowing for greater access and numerous types of research activities.

NSF Graduate Research Fellows 2008

photo of Sarah Lukes

The National Science Foundation’s Graduate Research Fellowship Program aims to ensure the vitality of the human resource base of science and engineering in the United States and to reinforce its diversity. The program recognizes and supports outstanding graduate students in the relevant science, technology, engineering, and mathematics disciplines who are pursuing research-based master’s and doctoral degrees.

This year NSF awarded 913 fellowships: which come with a stipend of $30,000 and $10,500 cost of education allowance. On the ASEE Science and Engineering Fellowship blog, that I manage in my full time job with the American Society for Engineering Education (the Curious Cat Science and Engineering blog is my own and not related to ASEE), we highlight awardees including: Sarah Lukes mechanical engineering graduate working on her PhD at Montana State University; Ben Safdi, engineering physics and applied mathematics dual major at Colorado University – Boulder; Henry Deyoung, computer science major at Carnegie Mellon University, Jennifer Robinson, computer science major at North Carolina State; Lydia ThÃ©, biology major at Swarthmore; and Julia Kamenetzky, physics major at Cornell College.

Fellows from previous years include: Sergey Brin, H. David Politzer and Eric Maskin.

Cosmology Questions Answered

A great list of Cosmology Questions Answered, including: Why do we think that the expansion of the Universe is accelerating? What is quintessence? What is the Universe expanding into?

Everything that we measure is within the Universe, and we see no edge or boundary or center of expansion. Thus the Universe is not expanding into anything that we can see, and this is not a profitable thing to think about. Just as Dali’s Corpus Hypercubicus is just a 2-D picture of a 3-D object that represents the surface of a 4-D cube, remember that the balloon analogy is just a 2-D picture of a 3-D situation that is supposed to help you think about a curved 3-D space, but it does not mean that there is really a 4-D space that the Universe is expanding into.

Brian Cox Particle Physics Webcast

TED webcast of Brian Cox discussing his work at CERN’s Large Hadron Collider. He does a very good job of explaining some of the basic science in understandable terms.