64 research outputs found
Transport in topological insulator nanowires
In this chapter we review our work on the theory of quantum transport in
topological insulator nanowires. We discuss both normal state properties and
superconducting proximity effects, including the effects of magnetic fields and
disorder. Throughout we assume that the bulk is insulating and inert, and work
with a surface-only theory. The essential transport properties are understood
in terms of three special modes: in the normal state, half a flux quantum along
the length of the wire induces a perfectly transmitted mode protected by an
effective time reversal symmetry; a transverse magnetic field induces chiral
modes at the sides of the wire, with different chiralities residing on
different sides protecting them from backscattering; and, finally, Majorana
zero modes are obtained at the ends of a wire in a proximity to a
superconductor, when combined with a flux along the wire. Some parts of our
discussion have a small overlap with the discussion in the review [Bardarson
and Moore, Rep. Prog. Phys., 76, 056501, (2013)]. We do not aim to give a
complete review of the published literature, instead the focus is mainly on our
own and directly related work.Comment: 22 pages, 8 figures; Chapter in "Topological Matter. Springer Series
in Solid-State Sciences, vol 190. Springer
Assumption without representation: the unacknowledged abstraction from communities and social goods
We have not clearly acknowledged the abstraction from unpriceable “social goods” (derived from
communities) which, different from private and public goods, simply disappear if it is attempted to
market them. Separability from markets and economics has not been argued, much less established.
Acknowledging communities would reinforce rather than undermine them, and thus facilitate
the production of social goods. But it would also help economics by facilitating our understanding
of – and response to – financial crises as well as environmental destruction and many social problems,
and by reducing the alienation from economics often felt by students and the public
Service QoS Composition at the Level of Part Names
The cornerstone for the success of Service-Oriented Computing lies in its promise to allow fast and easy composition of services to create added-value applications. Compositions need to be described in terms of their desired functional properties, but the non-functional properties are of paramount importance as well. Inspired by the Web Service challenge we propose a new model for describing the Quality of Service (QoS) of a composition which considers the information flow and describes basic service qualities at the granularity level of service part names, that is, operations comprised in service invocation/response messages. In this initial investigation, we overview a number of formal methods techniques that allow to reason with QoS composition based on the proposed model, and propose an algorithm for determining the QoS of a composition given the QoS associated with the individual services
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