Designing short robust NOT gates for quantum computation

Composite pulses, originally developed in Nuclear Magnetic Resonance (NMR), have found widespread use in experimental quantum information processing (QIP) to reduce the effects of systematic errors. Most pulses used so far have simply been adapted from existing NMR designs, and while techniques have been developed for designing composite pulses with arbitrary precision the results have been quite complicated and have found little application. Here I describe techniques for designing short but effective composite pulses to implement robust NOT gates, bringing together existing insights from NMR and QIP, and present some novel composite pulses.Comment: 12 pages RevTex including 7 figures; in press at Phys Rev

Crotalus transversus

Number of Pages: 3Integrative BiologyGeological Science

Science with the Virtual Observatory: the AstroGrid VO Desktop

We introduce a general range of science drivers for using the Virtual Observatory (VO) and identify some common aspects to these as well as the advantages of VO data access. We then illustrate the use of existing VO tools to tackle multi wavelength science problems. We demonstrate the ease of multi mission data access using the VOExplorer resource browser, as provided by AstroGrid (http://www.astrogrid.org) and show how to pass the various results into any VO enabled tool such as TopCat for catalogue correlation. VOExplorer offers a powerful data-centric visualisation for browsing and filtering the entire VO registry using an iTunes type interface. This allows the user to bookmark their own personalised lists of resources and to run tasks on the selected resources as desired. We introduce an example of how more advanced querying can be performed to access existing X-ray cluster of galaxies catalogues and then select extended only X-ray sources as candidate clusters of galaxies in the 2XMMi catalogue. Finally we introduce scripted access to VO resources using python with AstroGrid and demonstrate how the user can pass on the results of such a search and correlate with e.g. optical datasets such as Sloan. Hence we illustrate the power of enabling large scale data mining of multi wavelength resources in an easily reproducible way using the VO.Comment: 8 pages; 7 figures; proceedings of invited talk at "Multi wavelength astronomy and the Virtual Observatory" conference, December 2008, EuroVO-AIDA program, European Space Astronomy Centre, Spai