Dear Friends, On Thursday, May 2, there will be an ITAMP topical lunch discussion. Tea Room (P-226) @ CfA (60 Garden Street) Time: 12:00-1:30 As always pizza will be served. Speaker: Swati Singh Title: Nuclear Spin cooling in Diamond via Coherent Population Trapping Abstract: Interaction between an electronic state and its surrounding nuclear spin environment is a major source of decoherence in most artificial atomic systems. Recently, optical pumping techniques, including coherent population trapping were used to monitor and control the nuclear bath surrounding such solid state systems, including nitrogen vacancies (NV) in diamond and localized spins in semiconductors. We develop a semiclassical model reminiscent of velocity selective coherent population trapping (VSCPT) in atomic physics to explain the anomalous diffusion in the nuclear bath. We test our model by using it to explain the dark time distribution in experiments with NV centers in diamond, using it to estimate some nuclear bath parameters. Furthermore, the experimentally measured distribution of dark times is of a power law form, leading to the first direct demonstration of Lévy statistics in such spin systems. Looking forward to seeing you there, Misha Lemeshko -- Dr. Mikhail Lemeshko Institute for Theoretical Atomic, Molecular, and Optical Physics (ITAMP) Harvard-Smithsonian Center for Astrophysics MS-14 60 Garden St. Cambridge, MA 02138 U.S.A. mlemeshko(a)cfa.harvard.edu http://sites.google.com/site/mishalemeshko/ Tel. +1 (617) 496-7610 Fax +1 (617) 496-7668