18,149 research outputs found
Order theory and interpolation in operator algebras
We continue our study of operator algebras with and contractive approximate
identities (cais). In earlier papers we have introduced and studied a new
notion of positivity in operator algebras, with an eye to extending certain
C*-algebraic results and theories to more general algebras. Here we continue to
develop this positivity and its associated ordering, proving many foundational
facts. We also give many applications, for example to noncommutative topology,
noncommutative peak sets, lifting problems, peak interpolation, approximate
identities, and to order relations between an operator algebra and the
C*-algebra it generates. In much of this it is not necessary that the algebra
have an approximate identity. Many of our results apply immediately to function
algebras, but we will not take the time to point these out, although most of
these applications seem new.Comment: 27 pages. arXiv admin note: substantial text overlap with
arXiv:1308.272
Ideals and hereditary subalgebras in operator algebras
This paper may be viewed as having two aims. First, we continue our study of
algebras of operators on a Hilbert space which have a contractive approximate
identity, this time from a more Banach algebraic point of view. Namely, we
mainly investigate topics concerned with the ideal structure, and hereditary
subalgebras (HSA's), which are in some sense generalization of ideals. Second,
we study properties of operator algebras which are hereditary subalgebras in
their bidual, or equivalently which are `weakly compact'. We also give several
examples answering natural questions that arise in such an investigation.Comment: 24 page
A monotonicity conjecture for real cubic maps
This is an outline of work in progress. We study the conjecture that the
topological entropy of a real cubic map depends ``monotonely'' on its
parameters, in the sense that each locus of constant entropy in parameter space
is a connected set. This material will be presented in more detail in a later
paper
Interface Between Topological and Superconducting Qubits
We propose and analyze an interface between a topological qubit and a
superconducting flux qubit. In our scheme, the interaction between Majorana
fermions in a topological insulator is coherently controlled by a
superconducting phase that depends on the quantum state of the flux qubit. A
controlled phase gate, achieved by pulsing this interaction on and off, can
transfer quantum information between the topological qubit and the
superconducting qubit.Comment: 12 pages, 7 figures. V2: Final version as published in Phys. Rev.
Lett, with detailed clarifications in the Appendi
Simulation at Dryden Flight Research Facility from 1957 to 1982
The Dryden Flight Research Facility has been a leader in developing simulation as an integral part of flight test research. The history of that effort is reviewed, starting in 1957 and continuing to the present time. The contributions of the major program activities conducted at Dryden during this 25-year period to the development of a simulation philosophy and capability is explained
Factors in the Decision-Making of North Carolina Probation Officers
A questionnaire on eight revocation cases selected from state files revealed some discernible differences in decisions and ra tionalizations among 108 field officers of the North Carolina Probation Department. Lambda and Q measures of cross-tabu lated characteristics of the officers, decisions, and rationalizations showed that values tended to concentrate in cases characterized by a revoking pattern or extenuating circumstances and in case situations where the police or courts were holding the proba tioner or acting upon his violation. Most officers gave officer- oriented or social order reasons for their decisions rather than reasons that were probationer-oriented.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68483/2/10.1177_002242786600300205.pd
Cylindrical surface profile and diameter measuring tool and method
A tool is shown having a cross beam assembly made of beams joined by a center box structure. The assembly is adapted to be mounted by brackets to the outer end of a cylindrical case. The center box structure has a vertical shaft rotatably mounted therein and extending beneath the assembly. Secured to the vertical shaft is a radius arm which is adapted to rotate with the shaft. On the longer end of the radius arm is a measuring tip which contacts the cylindrical surface to be measured and which provides an electric signal representing the radius of the cylindrical surface from the center of rotation of the radius arm. An electric servomotor rotates the vertical shaft and an electronic resolver provides an electric signal representing the angle of rotation of the shaft. The electric signals are provided to a computer station which has software for its computer to calculate and print out the continuous circumference profile of the cylindrical surface, and give its true diameter and the deviations from the ideal circle
Elastic Differential Cross Sections for Space Radiation Applications
The eikonal, partial wave (PW) Lippmann-Schwinger, and three-dimensional
Lippmann- Schwinger (LS3D) methods are compared for nuclear reactions that are
relevant for space radiation applications. Numerical convergence of the eikonal
method is readily achieved when exact formulas of the optical potential are
used for light nuclei (A 16), and the momentum-space representation of
the optical potential is used for heavier nuclei. The PW solution method is
known to be numerically unstable for systems that require a large number of
partial waves, and, as a result, the LS3D method is employed. The effect of
relativistic kinematics is studied with the PW and LS3D methods and is compared
to eikonal results. It is recommended that the LS3D method be used for high
energy nucleon-nucleus reactions and nucleus-nucleus reactions at all energies
because of its rapid numerical convergence and stability
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