18,436 research outputs found
Neutrino factory in stages: Low energy, high energy, off-axis
We discuss neutrino oscillation physics with a neutrino factory in stages,
including the possibility of upgrading the muon energy within the same program.
We point out that a detector designed for the low energy neutrino factory may
be used off-axis in a high energy neutrino factory beam. We include the
re-optimization of the experiment depending on the value of theta_13 found. As
upgrade options, we consider muon energy, additional baselines, a detector mass
upgrade, an off-axis detector, and the platinum (muon to electron neutrino)
channels. In addition, we test the impact of Daya Bay data on the optimization.
We find that for large theta_13 (theta_13 discovered by the next generation of
experiments), a low energy neutrino factory might be the most plausible minimal
version to test the unknown parameters. However, if a higher muon energy is
needed for new physics searches, a high energy version including an off-axis
detector may be an interesting alternative. For small theta_13 (theta_13 not
discovered by the next generation), a plausible program could start with a low
energy neutrino factory, followed by energy upgrade, and then baseline or
detector mass upgrade, depending on the outcome of the earlier phases.Comment: 23 pages, 10 (color) figures. Minor clarifications and changes. Final
version to appear in PR
Kawasaki-type Dynamics: Diffusion in the kinetic Gaussian model
In this article, we retain the basic idea and at the same time generalize
Kawasaki's dynamics, spin-pair exchange mechanism, to spin-pair redistribution
mechanism, and present a normalized redistribution probability. This serves to
unite various order-parameter-conserved processes in microscopic, place them
under the control of a universal mechanism and provide the basis for further
treatment. As an example of the applications, we treated the kinetic Gaussian
model and obtained exact diffusion equation. We observed critical slowing down
near the critical point and found that, the critical dynamic exponent z=1/nu=2
is independent of space dimensionality and the assumed mechanism, whether
Glauber-type or Kawasaki-type.Comment: accepted for publication in PR
CORE: Augmenting Regenerating-Coding-Based Recovery for Single and Concurrent Failures in Distributed Storage Systems
Data availability is critical in distributed storage systems, especially when
node failures are prevalent in real life. A key requirement is to minimize the
amount of data transferred among nodes when recovering the lost or unavailable
data of failed nodes. This paper explores recovery solutions based on
regenerating codes, which are shown to provide fault-tolerant storage and
minimum recovery bandwidth. Existing optimal regenerating codes are designed
for single node failures. We build a system called CORE, which augments
existing optimal regenerating codes to support a general number of failures
including single and concurrent failures. We theoretically show that CORE
achieves the minimum possible recovery bandwidth for most cases. We implement
CORE and evaluate our prototype atop a Hadoop HDFS cluster testbed with up to
20 storage nodes. We demonstrate that our CORE prototype conforms to our
theoretical findings and achieves recovery bandwidth saving when compared to
the conventional recovery approach based on erasure codes.Comment: 25 page
Flux-lattice melting in LaOFFeAs: first-principles prediction
We report the theoretical study of the flux-lattice melting in the novel
iron-based superconductor and
. Using the Hypernetted-Chain closure and an
efficient algorithm, we calculate the two-dimensional one-component plasma pair
distribution functions, static structure factors and direct correlation
functions at various temperatures. The Hansen-Verlet freezing criterion is
shown to be valid for vortex-liquid freezing in type-II superconductors.
Flux-lattice meting lines for and
are predicted through the combination of the density
functional theory and the mean-field substrate approach.Comment: 5 pages, 4 figures, to appear in Phys. Rev.
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