23,234 research outputs found
Bosonic Super Liouville System: Lax Pair and Solution
We study the bosonic super Liouville system which is a statistical
transmutation of super Liouville system. Lax pair for the bosonic super
Liouville system is constructed using prolongation method, ensuring the Lax
integrability, and the solution to the equations of motion is also considered
via Leznov-Saveliev analysis.Comment: LaTeX, no figures, 11 page
Exact 1-D Model for Coherent Synchrotron Radiation with Shielding and Bunch Compression
Coherent Synchrotron Radiation has been studied effectively using a
1-dimensional model for the charge distribution in the realm of small angle
approximations and high energies. Here we use Jefimenko's form of Maxwell's
equations, without such approximations, to calculate the exact wake-fields due
to this effect in multiple bends and drifts. It has been shown before that the
influence of a drift can propagate well into a subsequent bend. We show, for
reasonable parameters, that the influence of a previous bend can also propagate
well into a subsequent bend, and that this is especially important at the
beginning of a bend. Shielding by conducting parallel plates is simulated using
the image charge method. We extend the formalism to situations with compressing
and decompressing distributions, and conclude that simpler approximations to
bunch compression usually overestimates the effect. Additionally, an exact
formula for the coherent power radiated by a Gaussian bunch is derived by
considering the coherent synchrotron radiation spectrum, and is used to check
the accuracy of wake-field calculations
Simulation of January 1-7, 1978 events
The solar wind disturbances of January 1 to 7, 1978 are reconstructed by a modeling method. First, the interplanetary magnetic field (IMF) background pattern, including a corotating shock, is reproduced using the Stanford source surface map. Then, two solar flares with their onset times on January 1, 0717 UT at S17 deg E10 deg and 2147 UT S17 deg E32 deg, respectively, are selected to generate two interplanetary transient shocks. It is shown that these two shocks interacted with the corotating shock, resulting in a series of interplanetary events observed by four spacecraft, Helios 1 and 2, IMP-8 (Interplanetary Monitoring Platform 8), and Voyager 2. Results show that these three shock waves interact and coalesce in interplanetary space such that Helios 2 and Voyager 2 observed only one shock and Helios 1 and IMP-8 observed two shocks. All shocks observed by the four spacecraft, except the corotating shock at Helios 1, are either a transient shock or a shock which is formed from coalescing of the transient shocks with the corotating shock. The method is useful in reconstructing a very complicated chain of interplanetary events observed by a number of spacecraft
transition form factor within Light Front Quark Model
We study the transition form factor of as a
function of the momentum transfer within the light-front quark model
(LFQM). We compare our result with the experimental data by BaBar as well as
other calculations based on the LFQM in the literature. We show that our
predicted form factor fits well with the experimental data, particularly those
at the large region.Comment: 11 pages, 4 figures, accepted for publication in PR
On the Classical Algebra
We consider the classical \w42 algebra from the integrable system viewpoint.
The integrable evolution equations associated with the \w42 algebra are
constructed and the Miura maps , consequently modifications, are presented.
Modifying the Miura maps, we give a free field realization the classical \w42
algebra. We also construct the Toda type integrable systems for it.Comment: 14 pages, latex, no figure
Quantum Creation of Topological Black Hole
The constrained instanton method is used to study quantum creation of a
vacuum or charged topological black hole. At the level, the relative
creation probability is the exponential of a quarter sum of the horizon areas
associated with the seed instanton.Comment: Report-no change onl
Optimal Dividend Payments for the Piecewise-Deterministic Poisson Risk Model
This paper considers the optimal dividend payment problem in
piecewise-deterministic compound Poisson risk models. The objective is to
maximize the expected discounted dividend payout up to the time of ruin. We
provide a comparative study in this general framework of both restricted and
unrestricted payment schemes, which were only previously treated separately in
certain special cases of risk models in the literature. In the case of
restricted payment scheme, the value function is shown to be a classical
solution of the corresponding HJB equation, which in turn leads to an optimal
restricted payment policy known as the threshold strategy. In the case of
unrestricted payment scheme, by solving the associated integro-differential
quasi-variational inequality, we obtain the value function as well as an
optimal unrestricted dividend payment scheme known as the barrier strategy.
When claim sizes are exponentially distributed, we provide easily verifiable
conditions under which the threshold and barrier strategies are optimal
restricted and unrestricted dividend payment policies, respectively. The main
results are illustrated with several examples, including a new example
concerning regressive growth rates.Comment: Key Words: Piecewise-deterministic compound Poisson model, optimal
stochastic control, HJB equation, quasi-variational inequality, threshold
strategy, barrier strateg
First measurements of the flux integral with the NIST-4 watt balance
In early 2014, construction of a new watt balance, named NIST-4, has started
at the National Institute of Standards and Technology (NIST). In a watt
balance, the gravitational force of an unknown mass is compensated by an
electromagnetic force produced by a coil in a magnet system. The
electromagnetic force depends on the current in the coil and the magnetic flux
integral. Most watt balances feature an additional calibration mode, referred
to as velocity mode, which allows one to measure the magnetic flux integral to
high precision. In this article we describe first measurements of the flux
integral in the new watt balance. We introduce measurement and data analysis
techniques to assess the quality of the measurements and the adverse effects of
vibrations on the instrument.Comment: 7 pages, 8 figures, accepted for publication in IEEE Trans. Instrum.
Meas. This Journal can be found online at
http://ieeexplore.ieee.org/xpl/RecentIssue.jsp?punumber=1
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