Department of Applied Physics and Materials Science - Applied Physics

News & Events


Weighing Molecules One at a Time


Michael L. Roukes, Robert M. Abbey Professor of Physics, Applied Physics, and Bioengineering as well as Co-Director of the Kavli Nanoscience Institute, and colleagues have created the first-ever mechanical device that measures the mass of a single molecule. The device—which is only a couple millionths of a meter in size—consists of a tiny, vibrating bridge-like structure. When a particle or molecule lands on the bridge, its mass changes the oscillating frequency in a way that reveals how much the particle weighs. [Caltech Press Release]

Tags: APhMS research highlights Michael Roukes

Solar Loops and Space Weather


Paul M. Bellan, Professor of Applied Physics, and colleagues have reproduced plasma loops in the laboratory to help understand solar physics. "We're studying how these solar loops work, which contributes to the knowledge of space weather," says Professor Bellan, who compares the research to studying hurricanes. For example, you can't predict a hurricane unless you know more about the events that precede it, like high-pressure and low-pressure fronts. The same is true for solar flares. "It takes some time for the plasma to get to Earth from the sun, so it's possible that with more research, we could have up to a two-day warning period for massive solar flares." [Caltech Release] [E&S Article]

Tags: APhMS energy research highlights Paul Bellan

Material's Spacing is Key to Brittle-to-ductile Transition


Julia R. Greer, her postdoctoral scholar Dr.Dongchan Jang, and colleagues have used experiments and atomistic simulations of nano-twinned metals (which have the unique combined effect of being strong and ductile) to decipher the specific role of the twin boundaries. They have found that it is the spacing between the twin boundaries that determines whether a material is brittle or ductile as opposed to the sample size, as would be expected. Greer states "this is probably the first study that truly isolated the twin boundaries by making samples which contained only twin boundaries, periodically spaced throughout the sample, and then tested them in tension. This understanding will help in the design of better structural materials and provide a certain amount of predictability in doing so, which has not been possible to date." [Nature Nanotechnology Article and Movies]

Tags: APhMS research highlights Julia Greer Dongchan Jang

Demonstrating the Quantum World at Macroscopic Scales


Keith Schwab, Professor of Applied Physics, and colleagues describe how, aided by optical cavities and superconducting circuits, researchers are coaxing ever-larger objects to wiggle, shake, and flex in ways that are distinctly quantum mechanical. [Physics Today Article] [Institute for Quantum Information and Matter]

Tags: APhMS research highlights Keith Schwab

The Physics of Going Viral


Rob Phillips, Fred and Nancy Morris Professor of Biophysics and Biology, and colleagues have measured the rate of DNA transfer from viruses to bacteria. They wanted to find out whether pressure plays a dominant role in transferring the DNA. Instead, he says, "What we discovered is that the thing that mattered most was not the pressure in the bacteriophage, but how much DNA was in the bacterial cell." When the bacteriophages try to inject their DNA into the cells, the factor that limits the rate of transfer is how jam-packed those cells are.  "In this case," Phillips says, "it had more to do with the recipient, and less to do with the pressure that had built up inside the phage." [Caltech Press Release]

Tags: APhMS research highlights health Rob Phillips

Winners of the 2012 Demetriades - Tsafka - Kokkalis Prizes Announced


The student winners of the 2012 Demetriades - Tsafka - Kokkalis Prizes were announced at a special luncheon with the Demetriades - Tsafka – Kokkalis family. Philip Romero received the prize in Biotechnology for his work on developing statistical models of proteins with Frances Arnold. Michael Mello was the recipient of the prize in Seismo-Engineering, Prediction, and Protection for his work with Ares Rosakis on developing a novel methodology for identifying the unique ground motion signatures of supershear earthquakes. Leslie O’Leary received the prize in Environmentally Benign Renewable Energy Sources for her pathbreaking work on the properties of semiconductor interfaces with Nate Lewis and Bob Grubbs. This year there were two winners for the prize in Nanotechnology. One winner was Andrew Jennings for his experimental and modeling work in nanomechanics with Julia Greer. The other winner of the Nanotechnology prize was Jordan Raney who has worked with Chiara Daraio to develop new chemical synthesis methods to control the properties of carbon nanotubes.

Tags: APhMS honors research highlights Chiara Daraio GALCIT MCE Nate Lewis Julia Greer Ares Rosakis Demetriades - Tsafka - Kokkalis Philip Romero Frances Arnold. Michael Mello Leslie O’Leary Bob Grubbs Andrew Jennings Jordan Raney

Liquid-like Materials May Pave Way for New Thermoelectric Devices


Jeff Snyder, Faculty Associate in Applied Physics and Materials Science, and colleagues have identified a liquid-like compound whose properties give it the potential to be even more efficient than traditional thermoelectrics. [Caltech Press Release]

Tags: APhMS energy research highlights Jeff Snyder

Plasmas Torn Apart


Using high-speed cameras to look at jets of plasma in the lab, Paul M. Bellan, Professor of Applied Physics, and colleagues have made a discovery that may be important in understanding phenomena like solar flares and in developing nuclear fusion as a future energy source. "Trying to understand nature by using engineering techniques is indeed a hallmark of the Division of Engineering and Applied Science at Caltech," says Ares Rosakis, Chair of the Engineering and Applied Science Division. [Caltech release] [Plasma movie]

Tags: APhMS energy research highlights Paul Bellan

Explaining Superconductivity at High Temperatures


William A. Goddard III, Charles and Mary Ferkel Professor of Chemistry, Materials Science, and Applied Physics, and colleagues have developed a hypothesis to explain the strange behavior of high-temperature superconductors—copper oxides, or cuprates, that conduct electricity without any resistance at temperatures much higher than other superconducting metals. Their hypothesis also points the way to a method for making even higher-temperature superconductors. [Caltech press release]

Tags: APhMS research highlights William Goddard

Four EAS Faculty Receive Named Chairs


Professors James (Jim) L. Beck, Sossina M. Haile, Melany L. Hunt, and Rob Phillips have received named chairs.  Jim Beck has been named the George W. Housner Professor of Engineering and Applied Science.  Sossina Haile has been named the Carl F Braun Professor of Materials Science and Chemical Engineering. Melany Hunt has been named the William R. Kenan, Jr. Professor of Mechanical Engineering. Rob Phillips has been named the Fred and Nancy Morris Professor of Biophysics and Biology.

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Tags: APhMS honors research highlights MCE Sossina Haile James Beck Rob Phillips Melany Hunt