Events on Thursday, February 16th, 2017
- R. G. Herb Condensed Matter Seminar
- Exploring the analogy between atoms and optical nanoresonators -- atomic metasurfaces, super-scattering, and super-radiant thermal emission
- Time: 10:00 am - 11:00 am
- Place: Chamberlin 5310
- Speaker: Zongfu Yu, UW-Madison
- Abstract: I will use a few examples to show that the exploration of the analogy between atoms and optical nano-resonators could be quite interesting and useful. In the first example, I will discuss how atoms might help to overcome the most daunting challenges in optical metasurfaces, which promise to revolutionize optical instruments by replacing delicate and expensive lenses with integrated flat components. Then, I will discuss quantum antenna, in an analogy to optical antenna. I will show how to drastically enhance the optical cross section of atoms using topologically nontrivial optical media. Lastly, I will discuss the effect of super-radiance in thermal radiation, which could provide an interesting way to control thermal energy conversion.
- Host: Vavilov
- NPAC (Nuclear/Particle/Astro/Cosmo) Forum
- Physics with a 10-year Color Movie of 40 Billion Stars and Galaxies
- Time: 1:30 pm
- Place: 5310 Chamberlin Hall
- Speaker: Keith Bechtol, Large Synoptic Survey Telescope
- Abstract: Steady advances in telescope and camera technology have allowed us to explore the night sky deeper, wider, and faster with each new generation of instruments. The next major experiment in this endeavor is the Large Synoptic Survey Telescope (LSST), now under construction in Chile, with first light scheduled in 2020. LSST will catalog more stars and galaxies than all previous astronomical surveys combined, and will monitor transient, variable, and moving objects over a ten-year period, generating ~10 million alerts each night. In addition to precision cosmological constraints for dark energy, dark matter, neutrino physics, and inflation, the resulting multipurpose dataset will enable discoveries in time-domain, Galactic, and Solar System astronomy. By turning the night sky into a giant publicly-accessible database, LSST will also create new opportunities for education and public outreach.<br><br>
- Host: Sridhara Dasu
- Astronomy Colloquium
- Systematic Serendipity: Novel Discoveries in Astronomical Surveys
- Time: 3:30 pm - 5:00 pm
- Place: 4421 Sterling Hall, Coffee and cookies 3:30 PM, Talk Begins 3:45 PM
- Speaker: Lucianne Walkowicz, Chicago Planetarium
- Abstract: As of last year, the Large Synoptic Survey Telescope (LSST) has begun construction on the summit of Cerro Pachon. As the top-rated flagship for ground-based astronomy in the next decade, LSST will provide an unprecedented dataset of 37 billion objects observed in both space and time. The time domain aspect of LSST is an especially promising source of new discoveries: the main survey is expected to generate new samples of thousands of supernovae, cataclysmic variables, stellar flares, and regular variables, amongst other denizens of the time-domain zoo, each one of which will generate an "alert" within 60 seconds of observation. Sorting amongst these transient and variable objects poses a challenging task: transient events of interest must be identified and prioritized, so that valuable follow-up resources (which are easily saturated by the volume of LSST alerts per night) are deployed on the events with the most potential to provide transformative understanding of particular phenomena. For LSST, this task is of course at a beyond-human scale, requiring sophisticated machine learning algorithms to provide real-time characterization and prioritization. However, another challenge looms under the surface of the approaching flood of data: how can truly novel phenomena be recognized and discovered in large datasets? In this talk, I will discuss methods and applications of finding anomalous data in astronomical datasets. Anomaly identification is a powerful means to both discover novel phenomena, as well as to identify problematic data so that it may be cleaned from the database. Lastly, hunting down anomalies is an exciting way to engage citizen scientists in astronomical discovery, whose efforts have repeatedly demonstrated the power of the crowd in uncovering previously-unnoticed phenomena.
- Host: Astronomy Department
- NPAC (Nuclear/Particle/Astro/Cosmo) Forum
- Unlocking neutrino mysteries with the NOvA experiment
- Time: 4:00 pm
- Place: 4274 Chamberlin Hall
- Speaker: Chris Backhouse, Caltech
- Abstract: The 2015 Nobel Prize in Physics was awarded for the discovery of the phenomenon of neutrino oscillations, which implies that neutrinos are not massless as we had previously believed. This raises a wealth of new and intriguing questions. What is the ordering of the neutrino mass states? Might they violate matter/antimatter symmetry? What structure, if any, does the neutrino mixing matrix have? The NOvA experiment directly addresses these questions by measuring changes undergone by a powerful neutrino beam over an 810km baseline, from its source at Fermilab, Illinois to a huge 14kton detector in Ash River, Minnesota. I will give a brief overview of neutrino oscillations, then present our latest results, their implications, and prospects for the future.
- Host: Sridhara Dasu