9,483 research outputs found
The A&A Experience With Impact Factors
There is a widespread impression that the scientific journal "Astronomy &
Astrophysics" (A&A) has a smaller impact, as measured by citations to articles,
than some of the other major astronomy journals. This impression was apparently
supported - and probably created - by the Journal Citation Report (JCR), which
is prepared annually by the Institute of Scientific Information (ISI) Web of
Knowledge. The published poor impact factor of A&A was in fact wrong and was
due to a serious flaw in the method used by ISI Web of Knowledge to determine
it. The resulting damage inflicted upon A&A by the JCR is incalculable.Comment: 4 pages, to be published in A. Heck (ed.) "Organizations and
Strategies in Astronomy, Vol. 5" (Kluwer, 2004
Braiding of non-Abelian anyons using pairwise interactions
The common approach to topological quantum computation is to implement
quantum gates by adiabatically moving non-Abelian anyons around each other.
Here we present an alternative perspective based on the possibility of
realizing the exchange (braiding) operators of anyons by adiabatically varying
pairwise interactions between them rather than their positions. We analyze a
system composed by four anyons whose couplings define a T-junction and we show
that the braiding operator of two of them can be obtained through a particular
adiabatic cycle in the space of the coupling parameters. We also discuss how to
couple this scheme with anyonic chains in order to recover the topological
protection.Comment: 8 pages, 7 figures. Errors corrected, clarifications and comments
adde
Single fermion manipulation via superconducting phase differences in multiterminal Josephson junctions
We show how the superconducting phase difference in a Josephson junction may
be used to split the Kramers degeneracy of its energy levels and to remove all
the properties associated with time reversal symmetry. The superconducting
phase difference is known to be ineffective in two-terminal short Josephson
junctions, where irrespective of the junction structure the induced Kramers
degeneracy splitting is suppressed and the ground state fermion parity must
stay even, so that a protected zero-energy Andreev level crossing may never
appear. Our main result is that these limitations can be completely avoided by
using multi-terminal Josephson junctions. There the Kramers degeneracy breaking
becomes comparable to the superconducting gap, and applying phase differences
may cause the change of the ground state fermion parity from even to odd. We
prove that the necessary condition for the appearance of a fermion parity
switch is the presence of a "discrete vortex" in the junction: the situation
when the phases of the superconducting leads wind by . Our approach
offers new strategies for creation of Majorana bound states as well as spin
manipulation. Our proposal can be implemented using any low density, high
spin-orbit material such as InAs quantum wells, and can be detected using
standard tools.Comment: Source code available as ancillary files. 10 pages, 7 figures. v2:
minor changes, published versio
Web Auctions in Europe
This paper argues that a better understanding of the business model of web auctions can be reached if we adopt a broader view and provide empirical research from different sites. In this paper the business model of web auctions is refined into four dimensions. These are auction model, motives, exchange processes, and stakeholders. One of the objects of this research is to redefine the blurry concept of the business model by analyzing one business model, the web auction model. We show in this research the complexity and diversity of factors contributing to the success of the web auction model. By generalizing the results to the level of business model we also show how complex and diverse business models can be. Motivated by the lack of empirically grounded justification for the mixed business results of web auctions, this paper adopts a qualitative approach that includes telephone interviews with web auctions developed in different European countries.exchange processes;stakeholders;Web auctions
Large Surveys in Cosmology: The Changing Sociology
Galaxy redshift surveys and Cosmic Microwave Background experiments are
undertaken with larger and larger teams, in a fashion reminiscent of particle
physics experiments and the human genome projects. We discuss the role of young
researchers, the issue of multiple authorship, and ways to communicate
effectively in teams of tens to hundreds of collaborators.Comment: Invited article for "Organizations and Strategies in Astronomy II",
ed. A. Heck, Kluwer Acad. Publ., in press (7 pages, no figures
Using SOWISO to realize interactive mathematical documents for learning, practicing, and assessing mathematics
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