Events at Physics
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Events During the Week of August 31st through September 7th, 2014
- No events scheduled
- Chaos & Complex Systems Seminar
- Writing a novel
- Time: 12:05 pm
- Place: 4274 Chamberlin Hall (Refreshments will be served)
- Speaker: Russell Gardner, Jr., Freelance scholar after psychiatry career without present institutional affiliation
- Abstract: Many people write novels. For example, I find many columns of the New York Times seem to have writers as intended readership (or those who wish to write). My own focus started suddenly on a late night near the end of February, 2012. In O’Hare Airport, standing on the tarmac I suddenly decided to include myself amongst the group, and from that moment began. I tell how this happened, and how I have tried to attain compositional skills in fiction, including lessons from books, conversations and trial runs, and now formal courses sponsored by the Madison Writers Studio taught by two novelists (MadisonWriters.com). At the time of this abstract, I am half through a year-long course entitled “Novel in a Year.” It involves writing 25-pages per month (in my case, sequential chapters) to accumulate by year’s end in a first draft. The structure itself has helped me. Previously I’ve felt stymied with lengthy prose of any kind, and suspect that it will stand me in good stead for efforts in the future.
In this presentation I plan to relate:
How the process began for me,
Fixed narrative features, roles of chance and imagination, "what's next?"
Characters, plot, and “center” or “novelist’s mysterious question,”
“Novel novel” vs “Old novel,”
Social relations in writing process, and
Fiction-writing vis-à-vis psychoanalysis.
- Host: Clint Sprott
- Theory Seminar (High Energy/Cosmology)
- Cosmology from the megaparsec to the micron
- Time: 4:00 pm
- Place: 5280 Chamberlin Hall
- Speaker: Amol Upadhye, University of Wisconsin-Madison
- Host: Ran Lu
- Department Meeting
- Time: 12:15 pm
- Place: 5310 Chamberlin Hall
- R. G. Herb Condensed Matter Seminar
- Multiplexing of Nanostructure Devices
- Time: 10:00 am
- Place: 5310 Chamberlin Hall
- Speaker: Dr. Luke Smith, University of Cambridge
- Abstract: It is highly desirable to increase the number of nanostructure devices on a single low temperature semiconductor chip for high through-put testing, and for creation of integrated quantum devices. We have developed an on-chip multiplexing technique which significantly increases the number of devices that can be measured during a single cooldown in a cryostat. This was used to address an array of 256 split gates on a GaAs/AlGaAs heterostructure; the largest number of such devices on an individual chip to date.
A rich variety of physical phenomena can be investigated using the split gate, despite the simple device geometry. Electron-electron interaction effects manifest in the formation of an anomalous conductance feature known as the ‘0.7 structure’, the specific origin of which is currently debated. We have performed a detailed statistical analysis of this structure using arrays of identical devices, as well as arrays in which the geometry of the split gates vary. Our results link this structure to small variations in the specific confining potential within individual devices.
Aside from exploring fundamental physics, the multiplexer can also be used to perform important tests of the suitability of nanostructure devices as elements for nanoelectronic or quantum computing architectures. We have performed yield studies, and investigated the reproducibility of device characteristics on repeated cooldowns. Additionally we have presented a technique which can be used to assess the homogeneity of the semiconducting substrate itself.
The multiplexing scheme is versatile and recently a charge-locking technique has been developed to sequentially bias a large number of gates, in order to form complex device structures. Initial studies have shown that this can be used to contact an array of quantum dots. Multiplexing is a powerful tool which both increases the efficiency of research and presents a new approach to measurements in this field.
- Host: Mark Eriksson
- Physics Department Colloquium
- Optical Atomic Clocks: A New Era of Precision Timekeeping
- Time: 3:30 pm
- Place: 2241 Chamberlin Hall (coffee at 4:30 pm)
- Speaker: Chris Oates, NIST-Boulder
- Abstract: The past decade has seen a revolution in atomic clocks that has advanced clock performance by more than two orders of magnitude. These new clocks, based on lasers stabilized to narrow optical transitions in trapped ions or atoms, use femtosecond lasers to link up with microwave or other optical clocks. I will describe our research on clocks based on neutral Yb atoms confined in an optical lattice, and highlight the key physical effects that need to be considered in optical clock design. Finally, I will highlight recent breakthroughs and show how optical clocks are used in tests of fundamental physics as well as precision timekeeping applications.
- Host: Walker