18,890 research outputs found
Representing non-weakly compact operators
For each (with a Banach space) the operator is defined by \quad (). We study mapping properties of the correspondence which
provides a representation of the weak Calkin algebra (here
denotes the weakly compact operators on ). Our results display
strongly varying behaviour of For instance, there are no non--zero compact
operators in Im in the case of and but
identifies isometrically with the class of lattice regular operators on
for (here is the James' space). Accordingly, there
is an operator such that is invertible but
fails to be invertible modulo $W(\ell^2(J)).
Masses of the Goldstone modes in the CFL phase of QCD at finite density
We construct the U_L(3) x U_R(3) effective lagrangian which encodes the
dynamics of the low energy pseudoscalar excitations in the Color-Flavor-Locking
superconducting phase of QCD at finite quark density. We include the effects of
instanton-induced interactions and study the mass pattern of the pseudoscalar
mesons. A tentative comparison with the analytical estimate for the gap
suggests that some of these low energy momentum modes are not stable for
moderate values of the quark chemical potential.Comment: 15 pages, 5 figures; Discussion of quark mass effects at very large
densities amended, references adde
Underlying events in Herwig++
In this contribution we describe the new model of multiple partonic
interactions (MPI) that has been implemented in Herwig++. Tuning its two free
parameters is enough to find a good description of CDF underlying event data.
We show extrapolations to the LHC and compare them to results from other
models.Comment: 4 pages, 3 figures, to appear in the proceedings of the "HERA and the
LHC" worksho
Multiple Interactions in Herwig++
In this contribution we describe a new model of multiple partonic
interactions that has been implemented in Herwig++. Tuning its two free
parameters we find a good description of CDF underlying event data. We show
extrapolations to the LHC and discuss intrinsic PDF uncertainties.Comment: 4 pages, 2 figures, to appear in the proceedings of the DIS 2008
workshop, 7-11 April 2008, University College Londo
Uncovering GPTS with Patent Data
This paper asks the question: Can we see evidence of General Purpose Technologies in patent data? Using data on three million US patents granted between 1967 and 1999, and their citations received between 1975 and 2002, we construct a number of measures of GPTs, including generality, number of citations, and patent class growth, for patents themselves and for the patents that cite the patents. A selection of the top twenty patents in the tails of the distribution of several of these measures yields a set of mostly ICT technologies, of which the most important are those underlying transactions on the internet and object-oriented software. We conclude with a brief discussion of the problems we encountered in developing our measures and suggestions for future work in this area.
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