Events at Physics
Events During the Week of March 1st through March 8th, 2015
- Plasma Physics (Physics/ECE/NE 922) Seminar
- Mitigating Disruptions in Tokamaks
- Time: 12:00 pm
- Place: 1610 Engineering Hall
- Speaker: Dr. Nick Eidietis, General Atomics
- Host: UW
- Council Meeting
- Time: 4:00 pm
- Place: 2314 Chamberlin (Chair's Conference Room)
- NPAC (Nuclear/Particle/Astro/Cosmo) Forum
- Faculty Candidate Seminar
- Fundamental Physics with Cosmic Microwave Background Polarimetry
- Time: 4:00 pm
- Place: 4274 Chamberlin Hall
- Speaker: Kam Arnold, UC San Diego, Center for Astrophysics & Space Sciences
- Abstract: The polarization of the cosmic microwave background (CMB) offers a unique window onto cosmology that can provide information about neutrinos, dark matter, dark energy, large-scale structure formation, and physics at 10^16 GeV energy scales. Several important measurements of CMB polarization were reported last year, including the first-season results from POLARBEAR. With those measurements, we showed the gravitational lensing of the CMB by large-scale structure using CMB polarization data alone, and a measurement of a non-zero B-mode polarization angular power spectrum.
Going forward, our expansion of POLARBEAR – the Simons Array – will produce more precise observations in multiple spectral bands over a large fraction of the sky. The Simons Array, powerful as a standalone experiment, is also a technological pathfinder for both the CMB-S4 experiment described in the Particle Physics Project Prioritization Panel report, and for the LiteBIRD satellite, which we recently proposed to NASA as a partner mission with JAXA. Together, the Simons Array and LiteBIRD will measure the sum of the neutrino masses with the precision necessary to determine their mass hierarchy, and make a deep search for the inflationary B-mode signal, producing a detection with significance > 10 sigma of the B-modes predicted by all large-field inflation models.
- Host: Dasu
- Chaos & Complex Systems Seminar
- Linking dynamics of chemistry, physiology and genetics in ecosystems through spectroscopy
- Time: 12:05 pm
- Place: 4274 Chamberlin Hall (Refreshments will be served)
- Speaker: Phil Townsend, UW Department of Forest &Wildlife Ecology
- Abstract: Contact and imaging spectroscopy show great promise for measurement of the physiology of ecosystems related both to environmental drivers and genetics. Over the last decade, researchers have demonstrated the use of reflectance spectroscopy to rapidly and accurately characterize features of ecosystems that previously entailed considerable monetary expense and effort, and/or were not thought to be mappable. We have discovered that plant spectra provide a record of plant traits and can be exploited to better understand their function in time and space. Though we do not understand all drivers of variation -- at leaf, canopy and ecosystem levels -- here I will provide evidence that we can infer properties ranging from gene expression to photosynthetic capacity to nutrient availability. For example, we have used spectroscopy to characterize forest response to insect herbivores and to track foliar chemistry as it is related to forest productivity and nutrient availability following logging. In agricultural settings, spectroscopy offers the capacity to measure the physiological effects of pests such as aphids and disease on plant physiology and ultimately yield. In aspen forests, we show how traits and genetics co-vary based on inferences from imaging spectroscopy. The potential future applications of these methods are extensive, and adaptation of spectrometers to deploy in a range of settings will enable us to bridge the gaps in spatial and temporal measurement capacity from the leaf/canopy to airborne to spaceborne levels.
- Host: Clint Sprott
- Department Meeting
- Time: 12:15 pm
- Place: 5310 Chamberlin Hall
- Astronomy Colloquium
- "News from the Extreme Energy Cliff"
- Time: 3:30 pm
- Place: 4421 Sterling Hall
- Speaker: Professor Angela Olinto, University of Chicago
- Abstract: Thanks to giant extensive air-showers observatories, such as the Pierre Auger Observatory and the Telescope Array (TA), we now know that the sources of ultrahigh energy cosmic rays (UHECRs) are extragalactic. We also know that either they interact with the CMB as predicted or they run out of energy at the same energy scale of the CMB interactions! Their composition is either surprising (dominated by heavier nuclei at the highest energies) or the hadronic interactions at 100 TeV are not a standard extrapolation of LHC interaction energies. Hints of anisotropies begin to appear as energies reach 60 EeV, just when statistics become very limited.
Basic questions remain unanswered: What generates such extremely energetic particles that reach above 10^20 eV (100 EeV)? Where do they come from? How do they reach these energies? What are they? How do they interact on their way to Earth and with the Earth’s atmosphere?
A hotspot seen by TA may be the first hint of a source. Neutrino and gamma-ray follow ups may clarify this tantalizing possibility. In addition, a large increase in statistics of UHECRs is needed. Space missions are now being studied to increase the exposure to UHECR such as the JEM-EUSO mission: the Extreme Universe Space Observatory (EUSO) at the Japanese Experiment Module (JEM).
- Cosmology Journal Club
- An Informal discussion about a broad variety of arXiv papers related to Cosmology
- Time: 12:15 pm
- Place: 5242 Chamberlin Hall
- Abstract: Please visit the following link for more details:
Please feel free to bring your lunch!
If you have questions or comments about this journal club, would like to propose a topic or volunteer to introduce a paper, please email Le Zhang (email@example.com)
- Host: Peter Timbie