Events at Physics |
Events on Tuesday, October 29th, 2013
- Chaos & Complex Systems Seminar
- DNA databasing for forensic use
- Time: 12:05 pm
- Place: 4274 Chamberlin (refreshments will be served)
- Speaker: Rohaizah James, Promega Corp
- Abstract: Genetic markers called Short Tandem Repeats (STR) is now routinely used in forensic DNA testing to identify the source of crime scene evidence. A DNA profile containing multiple STR's provides an extremely high probability of identity, leaving little doubt that a match between crime scene evidence and a suspect is not random. Because a large fraction of crimes are committed by repeat offenders, an offender database aids in generating leads and solving crimes. The national DNA database, established in 1998 after Congress passed the DNA Identification Act, now contains over 10 million offender DNA profiles. The ability to search this database has aided over 200,000 investigations. This database also includes over 1.5 million arrestee profiles. Arrestee DNA testing, currently allowed in 29 states, has been controversial. Does the potential benefit of improving public safety outweigh an arrestee's privacy interests? What about familial searching, where a database is searched to identify not the criminal but his/her biological relative? This search method was used successfully in solving the California Grim Sleeper case, where the presence of the criminalaEuroTMs son in the DNA database led investigators to the father. This presentation will include a discussion on the science behind STR analysis and the practical questions it brings in forensic use.
- Host: Clint Sprott
- Atomic Physics Seminar
- Steady-state switching and dispersion/absorption spectroscopy of multilevel atoms inside an optical ring cavity
- Time: 2:00 pm
- Place: to be reserved
- Speaker: Jiteng Sheng, University of Arkansas
- Abstract: Electromagnetically induced transparency (EIT) is essential in coherent atomic physics, which has been extensively studied in the last two decades. The important properties of EIT are its steep normal linear dispersion and greatly enhanced nonlinearity with a negligible absorption near atomic resonance. When EIT medium is placed inside an optical cavity, many interesting effects can occur. In this talk, I will discuss several experiments in EIT-related atom-cavity systems. Particular attention will be given to nonlinear optical cavity transmission spectra and optical multistate switching with Doppler-broadened multilevel atoms inside an optical ring cavity. In addition, parity-time symmetry and optically induced lattice in EIT-related medium will be briefly discussed.
- Host: Saffman
- Theory Seminar (High Energy/Cosmology)
- A second look at the string theory landscape
- Time: 4:00 pm
- Place: Chamberlin 5280
- Speaker: Thomas Van Riet, University of Leuven
- Abstract: I will review in a pedagogical manner the vanilla models (KKLT) that have lead to the conjecture of a string theory &quot;landscape&quot; of meta-stable de Sitter vacua. A central role is played by the so called uplifting anti-branes that break the supersymmetry of the AdS vacua and lift the cosmological constant to a positive value. In the last years it has become clear that the supergravity description of this process reveals problematic features such as unwanted singularities. Although this is a technical topic I will review it in a non technical fashion with an emphasis on the physics behind it. I will advocate the point of view that these singularities are easy to interpret and signal the instability of the vacuum. If correct this invalidates the original motivation for the landscape conjecture.<br><br>
- Host: Gary Shiu