Events at Physics |
Events on Thursday, December 3rd, 2009
- R. G. Herb Condensed Matter Seminar
- Recent Experiments to Probe Individual Spins of Few-Electron Silicon Quantum Dots
- Time: 10:00 am
- Place: 5310 Chamberlin
- Speaker: HongWen Jiang, UCLA
- Abstract: It is becoming increasingly apparent that qubits based on individual electron spins in Si quantum dots have considerable potential for scalable quantum information processing. Complementary to the active research efforts at Wisconsin, we at UCLA have developed a different type of electrostatically-confined quantum dots on Si MOS based materials. An array of electrical characterization shows that the quantum dots have unprecedented device stability and controllability. In this talk, I present results of transport measurements in the few electron regime. Unusual spin filling configurations, along with non-linear transport features associated with high-spin states will be reported. An integrated charge sensing channel adjacent to the quantum dot has been used to study the individual electron tunneling events and relaxation dynamics. The electron spin relaxation time T1 in the presence of an in-plane magnetic field is measured by the charge sensor with a pump-and-probe technique. I will discuss mechanisms leading to spin relaxation in this type of Si device.
- Host: Susan Coppersmith
- NPAC (Nuclear/Particle/Astro/Cosmo) Forum
- Acoustic Detection of Ultra-high Energy Neutrinos
- Time: 4:00 pm
- Place: 5310 Chamberlin
- Speaker: Naoko Kurahashi, Stanford
- Abstract: Study of Acoustic Ultra-high energy Neutrino Detection (SAUND) phase II uses 1000km^2 of ocean as a neutrino detector. SAUND<br>
aims to detect comic ray neutrinos of GZK energies and beyond<br>
(>10^18eV) acoustically by utilizing the ocean water as the target and an existing US Navy underwater microphone array as sensors. A DAQ system was developed and deployed in 2005. The experiment ran during 2006 and 2007, collecting over 1 TB of data with over 100 days of cumulative livetime. A study of the ocean ambient noise was performed using SAUND data, characterising the background for neutrino signals. Data analysis to isolate signals is performed in parallel to Monte Carlo studies of the detector to optimize cut efficiencies and set a neutrino flux limit in the ultra-high energy region. - Host: Teresa Montaruli