14,806 research outputs found
The Bosonic Structure of Fermions
We bosonize fermions by identifying their occupation numbers as the binary
digits of a Bose occupation number. Unlike other schemes, our method allows
infinitely many fermionic oscillators to be constructed from just one bosonic
oscillator.Comment: 7pages, ADP-94-13/T15
A Generic Conceptual Model for Risk Analysis in a Multi-agent Based Collaborative Design Environment
Organised by: Cranfield UniversityThis paper presents a generic conceptual model of risk evaluation in order to manage the risk through
related constraints and variables under a multi-agent collaborative design environment. Initially, a hierarchy
constraint network is developed to mapping constraints and variables. Then, an effective approximation
technique named Risk Assessment Matrix is adopted to evaluate risk level and rank priority after probability
quantification and consequence validation. Additionally, an Intelligent Data based Reasoning Methodology
is expanded to deal with risk mitigation by combining inductive learning methods and reasoning
consistency algorithms with feasible solution strategies. Finally, two empirical studies were conducted to
validate the effectiveness and feasibility of the conceptual model.Mori Seiki – The Machine Tool Compan
Single-shot electro-optic sampling of coherent transition radiation at the A0 Photoinjector
Future collider applications and present high-gradient laser plasma wakefield
accelerators operating with picosecond bunch durations place a higher demand on
the time resolution of bunch distribution diagnostics. This demand has led to
significant advancements in the field of electro-optic sampling over the past
ten years. These methods allow the probing of diagnostic light such as coherent
transition radiation or the bunch wakefields with sub-picosecond time
resolution. Potential applications in shot-to-shot, non-interceptive
diagnostics continue to be pursued for live beam monitoring of collider and
pump-probe experiments. Related to our developing work with electro-optic
imaging, we present results on single-shot electro-optic sampling of the
coherent transition radiation from bunches generated at the A0 photoinjector.Comment: 3 p
The Witten equation, mirror symmetry and quantum singularity theory
For any non-degenerate, quasi-homogeneous hypersurface singularity, we
describe a family of moduli spaces, a virtual cycle, and a corresponding
cohomological field theory associated to the singularity. This theory is
analogous to Gromov-Witten theory and generalizes the theory of r-spin curves,
which corresponds to the simple singularity A_{r-1}.
We also resolve two outstanding conjectures of Witten. The first conjecture
is that ADE-singularities are self-dual; and the second conjecture is that the
total potential functions of ADE-singularities satisfy corresponding
ADE-integrable hierarchies. Other cases of integrable hierarchies are also
discussed.Comment: To appear in Annals of Mathematics. Includes resolution of the Witten
ADE integrable hierarchies conjecture and Witten's ADE self-mirror
conjecture. Several corrections and clarification
Newtonian Flow in Converging-Diverging Capillaries
The one-dimensional Navier-Stokes equations are used to derive analytical
expressions for the relation between pressure and volumetric flow rate in
capillaries of five different converging-diverging axisymmetric geometries for
Newtonian fluids. The results are compared to previously-derived expressions
for the same geometries using the lubrication approximation. The results of the
one-dimensional Navier-Stokes are identical to those obtained from the
lubrication approximation within a non-dimensional numerical factor. The
derived flow expressions have also been validated by comparison to numerical
solutions obtained from discretization with numerical integration. Moreover,
they have been certified by testing the convergence of solutions as the
converging-diverging geometries approach the limiting straight geometry.Comment: 23 pages, 5 figures, 1 table. This is an extended and improved
version. arXiv admin note: substantial text overlap with arXiv:1006.151
Synchroscan streak camera imaging at a 15-MeV photoinjector with emittance exchange
At the Fermilab A0 photoinjector facility, bunch-length measurements of the
laser micropulse and the e-beam micropulse have been done in the past with a
fast single-sweep module of the Hamamatsu C5680 streak camera with an intrinsic
shot-to-shot trigger jitter of 10-20ps. We have upgraded the camera system with
the synchroscan module tuned to 81.25MHz to provide synchronous summing
capability with less than 1.5ps FWHM trigger jitter and a phase-locked delay
box to provide phase stability of ~1ps over 10s of minutes. These steps allowed
us to measure both the UV laser pulse train at 263nm and the e-beam via optical
transition radiation (OTR). Due to the low electron beam energies and OTR
signals, we typically summed over 50 micropulses with 0.25-1nC per micropulse.
The phase-locked delay box allowed us to assess chromatic temporal effects and
instigated another upgrade to an all-mirror input optics barrel. In addition,
we added a slow sweep horizontal deflection plug-in unit to provide dual-sweep
capability for the streak camera. We report on a series of measurements made
during the commissioning of these upgrades including bunch-length and phase
effects using the emittance exchange beamline and simultaneous imaging of a UV
drive laser component, OTR, and the 800nm diagnostics laser.Comment: 26 p
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