How to efficiently select an arbitrary Clifford group element

We give an algorithm which produces a unique element of the Clifford group C_n on n qubits from an integer 0\le i < |C_n| (the number of elements in the group). The algorithm involves O(n^3) operations. It is a variant of the subgroup algorithm by Diaconis and Shahshahani which is commonly applied to compact Lie groups. We provide an adaption for the symplectic group Sp(2n,F_2) which provides, in addition to a canonical mapping from the integers to group elements g, a factorization of g into a sequence of at most 4n symplectic transvections. The algorithm can be used to efficiently select randomelements of C_n which is often useful in quantum information theory and quantum computation. We also give an algorithm for the inverse map, indexing a group element in time O(n^3).Comment: 7 pages plus 4 1/2 pages of python cod

Is there an output-inflation trade-off?

Inflation (Finance)

Feasibility of modifying the high resolution infrared radiation sounder (HIRS/2) for measuring spectral components of Earth radiation budget

The concept of adding four spectral channels to the 20 channel HIRS/2 instrument for the purpose of determining the origin and profile of radiant existence from the Earth's atmosphere is considered. Methods of addition of three channels at 0.5, 1.0 and 1.6 micron m to the present 0.7 micron m visible channel and an 18-25 micron m channel to the present 19 channels spaced from 3.7 micron m to 15 micron m are addressed. Optical components and physical positions were found that permit inclusion of these added channels with negligible effect on the performance of the present 20 channels. Data format changes permit inclusion of the ERB data in the 288 bits allocated to HIRS for each scan element. A lamp and collimating optic assembly may replace one of the on board radiometric black bodies to provide a reference source for the albedo channels. Some increase in instrument dimensions, weight and power will be required to accommodate the modifications

A Distributed Economics-based Infrastructure for Utility Computing

Existing attempts at utility computing revolve around two approaches. The first consists of proprietary solutions involving renting time on dedicated utility computing machines. The second requires the use of heavy, monolithic applications that are difficult to deploy, maintain, and use. We propose a distributed, community-oriented approach to utility computing. Our approach provides an infrastructure built on Web Services in which modular components are combined to create a seemingly simple, yet powerful system. The community-oriented nature generates an economic environment which results in fair transactions between consumers and providers of computing cycles while simultaneously encouraging improvements in the infrastructure of the computational grid itself.Comment: 8 pages, 1 figur

The hydrogen atom in electric and magnetic fields : Pauli's 1926 article

The results obtained by Pauli, in his 1926 article on the hydrogen atom, made essential use of the dynamical so(4) symmetry of the bound states. Pauli used this symmetry to compute the perturbed energy levels of an hydrogen atom in a uniform electric field (Stark effect) and in uniform electric and magnetic fields. Although the experimental check of the single Stark effect on the hydrogen atom has been studied experimentally, Pauli's results in mixed fields have been studied only for Rydberg states of rubidium atoms in crossedfields and lithium atoms in parallel fields.Comment: 11 pages, latex file, 2 figure

New Results on e+e- Line Emission in U+Ta Collisions

We present new results obtained from a series of follow-up e+e- coincidence measurements in heavy-ion collisions, utilizing an improved experimental set-up at the double-Orange beta-spectrometer of GSI. The collision system U+Ta was reinvestigated in three independent runs at beam energies in the range (6.0-6.4)xA MeV and different target thicknesses, with the objective to reproduce a narrow sum-energy e+e- line at ~635 keV observed previously in this collision system. At improved statistical accuracy, the line could not be found in these new data. For the ''fission'' scenario, an upper limit (1 sigma) on its production probability per collision of 1.3x10^{-8} can be set which has to be compared to the previously reported value of [4.9 +- 0.8 (stat.) +- 1.0 (syst)]x10^{-7}. In the light of the new results, a reanalysis of the old data shows that the continuous part of the spectrum at the line position is significantly higher than previously assumed, thus reducing the production probability of the line by a factor of two and its statistical significance to < 3.4sigma.Comment: 15 pages, standard LaTeX with 3 included PS figures; Submitted to Physics Letters

Parent Resource Packet - A Guide for New Parents

PDF pages: 8

Sanctuary in the City of Brotherly Love: Probing the Effectiveness and Broader Implications of Philadelphia’s Sanctuary City Policies

Amidst the already fraught politics of immigration, “sanctuary” policies, whereby state and local law enforcement agencies limit their cooperation with federal immigration enforcement authorities to varying degrees, have emerged as a particularly contentious issue. This paper sifts past the political vitriol surrounding the issue of “sanctuary” and uses original survey research in Philadelphia to answer a straightforward question: Are these policies working? That is, are the city of Philadelphia’s sanctuary policies actually building trust between its undocumented residents and local law enforcement, thereby laying the groundwork for higher rates of crime reporting and safer communities? My results from a survey (with a telling embedded treatment effect experiment) of undocumented Philadelphians indicates that the city’s sanctuary policies are in fact serving their intended objectives. When coupled with the recent debates in the state legislature surrounding the issue of “sanctuary,” my results beg difficult questions regarding the development of American federalism and the proper division of authority between states and municipalities