iCalendar (*.ics extension) is a popular file format used to distribute calendar information between different applications over the internet.
Once you click the iCal feed link with the right button, copy the link URL and paste it into any calendar app that takes iCal feeds (Google Calendar, Outlook, etc).
Left click on a single event downloads the *.ics file with selected event, but it will not allow calendar apps to update automatically their calendar with other or upcoming events.
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Physics Conference Room, SB B326
Coffee starts at 12:00 PM and talk starts at 12:15 PM
- Monday, February 3, 2014
ABSTRACT: Living objects at the nanoscale can be viewed as molecular complexes, whose dynamics is often controlled by the transfer of single charges or single-photon absorption events. In many senses, it is similar to the principles of operation of semiconductor nanostructures and elements of molecular electronics. Correspondingly, the methods of condensed matter and statistical physics can be applied.
In this talk, I address proton-pumping complexes and proton-driven nanomotor of the mitochondria membranes. These systems convert the energy obtained from the food to the proton gradient across the membrane, to the mechanical rotation of the nanomotor, and, finally, to the energy of chemical compounds. We propose simple physical models for these complexes which not only allow the quantitative description but can inspire the implementations in nanoelectronics as well.
In the end of the talk, I discuss some details of electron transfer calculations bridging the Marcus theory and equations of motion, two methods widely used in chemistry and physics, respectively. We demonstrate that as a manifestation of the Goldilocks principle, the optimal transfer is governed by a single parameter which is equal to just the inverse square root of two.
- Monday, February 10, 2014
ABSTRACT: The Discrete Amplification Photon Detection technology enables a unique photodetector, in which a combination of an avalanche and negative-feedback mechanisms produces ultra-sensitive, very high gain, low noise, very small pixel size photodetectors and photodetector arrays. The discrete amplification physical mechanism is not dependent on the ratio of electrons and holes ionization coefficients, thus it can be implemented in several compound semiconductor material systems, such as silicon, GaAs/AlGaAs, and InGaAs/InGaAsP/InP. This talk describes the operation principle of the technology, the advantages and tradeoffs, as well as how this technology compares to, and differs from, other competing high sensitivity approaches. As this technology can detect single photons, single-photon detection and characterization will be described, as well as other low-light level threshold detection methodologies used to characterize the Discrete Amplification photodetectors. Record setting sensitivity results at room temperature detection using 1.5 micron wavelength-sensitive detectors will be presented. In addition, the development status of the technology, development plans and challenges for the two main applications, night vision and ranging, will be described.
- Friday, February 14, 2014
NOTES: Event starts at 4:00 PM on Friday
- Monday, February 24, 2014
- Monday, March 3, 2014
ABSTRACT: Recent progress in femtosecond electronic spectroscopy brought renewed interest in the transfer of electronic excitation energies in large molecular complexes. In particular, there have been speculations that the energy transfer in some photosynthetic light harvesting complexes may involve wave-like coherent quantum dynamics motion rather than the rate behavior. However, to what extent the quantum coherence is detrimental to efficient and robust energy transfer has remained a controversial issue. Advanced level of theories and development of reliable quantum mechanical models are crucial for quantitative resolution of such issue. This talk will present a range of theories developed recently, which can address nonequilibrium effects, quantum coherence, and soft nature of molecular environments for a fairly general class of systems. The talk will also discuss exciton-bath modeling of photosynthetic light harvesting complexes and quantum dynamical calculation of energy transfer dynamics. These results suggest that quantum coherence can play a subtle but significant role in minimizing the negative effects of thermal fluctuations and disorder in order to create both efficient and robust energy transfer dynamics mechanism.
- Monday, March 10, 2014
ABSTRACT: Many of the topological insulators, in their naturally available form are not insulating in the bulk. It has been shown that some of these metallic compounds, become superconductor at low enough temperature and the nature of their superconducting phase is still widely debated. In this talk I show that even the s-wave superconducting phase of doped topological insulators, at low doping, is different from ordinary s-wave superconductors and goes through a topological phase transition to an ordinary s-wave state by increasing the doping. I show that the critical doping is determined using the SU(2) Berry phase on the fermi surface of doped topological insulator and can be modified by different tunable features of the material. At the end I present the results of a recent experiment on the Josephson junctions made of thin films of Bismuth selenide , which can be explained using our theory of doping induced phase transition in topological insulators.
- Monday, March 24, 2014
ABSTRACT: In contrast to embryonic stem cells, adult stem cells are subject to differentially small changes in the mechanical, morphological, and chemical cues. The nature of the response may provide us with a better understanding of the role of stem cells in tissue regeneration, wound healing, and aging. Here we discuss how new materials can be engineered where each of these factors can be varied independently such that their influence on stem cell response can be assessed both individually and collectively.
- Monday, March 31, 2014
ABSTRACT: The first commercial optical communications system was deployed over 30 years ago, since that time new technologies have dramatically enhanced the capabilities of optical networks. The explosive growth of the Internet has been enabled by these technical innovations, and this trend continues. The early simple point-to-point links have been replaced with systems with more than 105 times more capacity per fiber, connected in a sophisticated mesh network. This talk will survey the history of optical communications, with special emphasis on recent innovations that enable the optical layer to be more agile than ever before.
Sheryl Woodward received her Ph.D. degree in Physics from Caltech. For over 25 years she has been in AT&T’s research organization - first with the Crawford Hill Laboratory of Bell Labs Research, and then with AT&T Labs-Research in Middletown, NJ. She has done research on topics ranging from technologies for cable television to optical networking for continental-backbone networks. Her current research focuses on software-defined networking for the wide-area network.
Steve G. Greenbaum
- Monday, April 7, 2014
ABSTRACT: Fundamental materials research is essential to move present-day energy storage technologies to the scale needed to develop all-electric vehicles and to manage intermittent renewable sources such as wind and solar. Comparable advances are also required to develop compact power sources for new medical and military/aerospace applications. Structural studies of materials utilized in lithium battery technology are often hampered by the lack of long-range order found only in well-defined crystalline phases. Powder x-ray diffraction yields only structural parameters that have been averaged over hundreds of lattice sites, and is unable to provide structural information about amorphous compounds. Our laboratory utilizes solid state nuclear magnetic resonance (NMR) methods to investigate structural and chemical aspects of lithium ion cathodes, anodes, electrolytes, interfaces and interphases. NMR is element- (nuclear-) specific and sensitive to small variations in the immediate environment of the ions being probed, for example Li+, and in most cases is a reliably quantitative spectroscopy in that the integrated intensity of a particular spectral component is directly proportional to the number of nuclei in the corresponding material phase. NMR is also a powerful tool for probing ionic and molecular motion in lithium battery electrolytes with a dynamic range spanning some ten orders of magnitude through spin-lattice relaxation and self-diffusion measurements. Brief summaries of several recent NMR investigations will be presented: (i) single crystal studies of LiMPO4 (M = Fe, Co, Ni) lithium ion battery cathodes; (ii) electrode passivation in lithium ion batteries; (iii) charge transfer in hybrid CFx/silver vanadate cathodes for medical devices; (iv) structure and dynamics of disordered fast-ion conducting Li3PS4 electrolytes for Li-S batteries.
- Monday, April 28, 2014
ABSTRACT: One of the major challenges in physics is to understand how the classical behavior of macroscopic objects emerges in a universe whose laws are fundamentally quantum mechanical. The field of optomechanics attempts to address this issue by studying the quantum behavior of devices in which a macroscopic object’s motion is coupled to individual photons. In the past few years, experiments have demonstrated a number of quantum effects in these devices, including ground-state cooling, entanglement, and the quantum back-action of displacement measurements. I will give an overview of our group's work on these topics. I will also designs for substantially improved optomechanical devices that consist entirely of superfluid helium.
- Wednesday, April 30, 2014
Australian National University
- Monday, May 5, 2014
- Wednesday, May 7, 2014