Single Spin Measurement using Single Electron Transistors to Probe Two Electron Systems

We present a method for measuring single spins embedded in a solid by probing two electron systems with a single electron transistor (SET). Restrictions imposed by the Pauli Principle on allowed two electron states mean that the spin state of such systems has a profound impact on the orbital states (positions) of the electrons, a parameter which SET's are extremely well suited to measure. We focus on a particular system capable of being fabricated with current technology: a Te double donor in Si adjacent to a Si/SiO2 interface and lying directly beneath the SET island electrode, and we outline a measurement strategy capable of resolving single electron and nuclear spins in this system. We discuss the limitations of the measurement imposed by spin scattering arising from fluctuations emanating from the SET and from lattice phonons. We conclude that measurement of single spins, a necessary requirement for several proposed quantum computer architectures, is feasible in Si using this strategy.Comment: 22 Pages, 8 Figures; revised version contains updated references and small textual changes. Submitted to Phys. Rev.

Revisão de Euprepina Hull (Diptera, Bombyliidae, Bombyliinae) Revision of Euprepina Hull (Diptera, Bombyliidae, Bombyliinae)

<abstract language="eng">Euprepina Hull, 1971 (Diptera, Bombyliidae, Bombyliinae) a neotropical genus with ten species is revised. Redescriptions of eight species were made: E. nuda Hull, 1971, E. amabilis (Wulp, 1881), E. beckeri Lamas & Couri, 1998, E. bicincta (Wiedemann, 1830), E. caminaria (Wiedemann, 1830), E. knutsoni Hull, 1971, E. maracajula Hull, 1971 and E. truxalia Hull, 1971, with illustrations of the types, male terminalia and spermathecae. Two synonymies - E. bicincta (Wiedemann, 1830), syn.: E. bicincta Hull, 1971; and E. nuda Hull, 1971, syn.: E. shannoni Hull, 1971 - are proposed. A key to species are presented except to E. goyaz (Macquart, 1840) and E. aperta (Macquart, 1847), which were not included in this study, as no material was examined