8,395 research outputs found
Evaluating application vulnerability to soft errors in multi-level cache hierarchy
As the capacity of cache increases dramatically with new processors, soft errors originating in cache has become a major reliability concern for high performance processors. This paper presents application specific soft error vulnerability analysis in order to understand an application's responses to soft errors from different levels of caches. Based on a high-performance processor simulator called Graphite, we have implemented a fault injection framework that can selectively inject bit flips to different levels of caches. We simulated a wide range of relevant bit error patterns and measured the applications' vulnerabilities to bit errors. Our experimental results have shown the various vulnerabilities of applications to bit errors from different levels of caches; the results have also indicated the probabilities of different behaviors from the applications
Classification and Asymptotic Scaling of Hadron Light-Cone Wave-Function Amplitudes
We classify the hadron light-cone wave-function amplitudes in terms of parton
helicity, orbital angular momentum, and quark flavor and color symmetries. We
show in detail how this is done for the pion, meson, nucleon, and delta
resonance up to and including three partons. For the pion and nucleon, we also
consider four-parton amplitudes. Using the scaling law derived recently, we
show how these amplitudes scale in the limit that all parton transverse momenta
become large.Comment: 28 pages, no figur
Generalized Bergman kernels on symplectic manifolds
We study the near diagonal asymptotic expansion of the generalized Bergman
kernel of the renormalized Bochner-Laplacian on high tensor powers of a
positive line bundle over a compact symplectic manifold. We show how to compute
the coefficients of the expansion by recurrence and give a closed formula for
the first two of them. As consequence, we calculate the density of states
function of the Bochner-Laplacian and establish a symplectic version of the
convergence of the induced Fubini-Study metric. We also discuss generalizations
of the asymptotic expansion for non-compact or singular manifolds as well as
their applications. Our approach is inspired by the analytic localization
techniques of Bismut-Lebeau.Comment: 48 pages. Add two references on the Hermitian scalar curvatur
Bulk Majorons at Colliders
Lepton number violation may arise via the spontaneous breakdown of a global
symmetry. In extra dimensions, spontaneous lepton number violation in the bulk
implies the existence of a Goldstone boson, the majoron J^(0), as well as an
accompanying tower of Kaluza-Klein (KK) excitations, J^(n). Even if the
zero-mode majoron is very weakly interacting, so that detection in low-energy
processes is difficult, the sum over the tower of KK modes may partially
compensate in processes of relevance at high-energy colliders. Here we consider
the inclusive differential and total cross sections for e^- e^- --> W^- W^- J,
where J represents a sum over KK modes. We show that allowed parameter choices
exist for which this process may be accessible to a TeV-scale electron
collider.Comment: 11 pages LaTeX, 3 eps figures (references added
Recent Results from Jefferson Lab
Recent results on studies of the structure of nucleons and nuclei in the
regime of strong interaction QCD are discussed. Use of high current polarized
electron beams, polarized targets, and recoil polarimeters, in conjunction with
modern spectrometers and detector instrumentation allow much more detailed
studies of nucleon and nuclear structure than has been possible in the past.
The CEBAF accelerator at Jefferson Lab was build to study the internal
structure of hadrons in a regime where confinement is important and strong
interaction QCD is the relevant theory. I discuss how the first experiments
already make significant contributions towards an improved understanding of
hadronic structure.Comment: Lecture presented at the International School of Nuclear Physics,
Erice, Sicily, Italy, September 17 - 25, 199
Prepulse Inhibition of Auditory Cortical Responses in the Caudolateral Superior Temporal Gyrus in Macaca mulatta
Prepulse inhibition (PPI) refers to a decreased response to a startling stimulus when another weaker stimulus precedes it. Most PPI studies have focused on the physiological startle reflex and fewer have reported the PPI of cortical responses. We recorded local field potentials (LFPs) in four monkeys and investigated whether the PPI of auditory cortical responses (alpha, beta, and gamma oscillations and evoked potentials) can be demonstrated in the caudolateral belt of the superior temporal gyrus (STGcb). We also investigated whether the presence of a conspecific, which draws attention away from the auditory stimuli, affects the PPI of auditory cortical responses. The PPI paradigm consisted of Pulse-only and Prepulse + Pulse trials that were presented randomly while the monkey was alone (ALONE) and while another monkey was present in the same room (ACCOMP). The LFPs to the Pulse were significantly suppressed by the Prepulse thus, demonstrating PPI of cortical responses in the STGcb. The PPI-related inhibition of the N1 amplitude of the evoked responses and cortical oscillations to the Pulse were not affected by the presence of a conspecific. In contrast, gamma oscillations and the amplitude of the N1 response to Pulse-only were suppressed in the ACCOMP condition compared to the ALONE condition. These findings demonstrate PPI in the monkey STGcb and suggest that the PPI of auditory cortical responses in the monkey STGcb is a pre-attentive inhibitory process that is independent of attentional modulation.Peer reviewe
Production of four-quark states with double heavy quarks at LHC
We study the hadronic production of four-quark states with double heavy
quarks and double light antiquarks at LHC. The production mechanism is that a
color anti-triplet diquark cluster consisting of double heavy quarks is formed
first from the produced double heavy quark-antiquark pairs via fusion hard
process, followed by the fragmentation of the diquark cluster into a four-quark
(tetraquark) state. Predictions for the production cross sections and their
differential distributions are presented. Our results show that it is quite
promising to discover these tetraquark states in LHC experiments both for large
number events and for their unique signatures in detectors.Comment: 17 pages,8 figure
XXZ and Ising Spins on the Triangular Kagome Lattice
The recently fabricated two-dimensional magnetic materials Cu9X2(cpa)6.xH2O
(cpa=2-carboxypentonic acid; X=F,Cl,Br) have copper sites which form a
triangular kagome lattice (TKL), formed by introducing small triangles
(``a-trimers'') inside of each kagome triangle (``b-trimer''). We show that in
the limit where spins residing on b-trimers have Ising character, quantum
fluctuations of XXZ spins residing on the a-trimers can be exactly accounted
for in the absence of applied field. This is accomplished through a mapping to
the kagome Ising model, for which exact analytic solutions exist. We derive the
complete finite temperature phase diagram for this XXZ-Ising model, including
the residual zero temperature entropies of the seven ground state phases.
Whereas the disordered (spin liquid) ground state of the pure Ising TKL model
has macroscopic residual entropy ln72=4.2767... per unit cell, the introduction
of transverse(quantum) couplings between neighboring -spins reduces this
entropy to 2.5258... per unit cell. In the presence of applied magnetic field,
we map the TKL XXZ-Ising model to the kagome Ising model with three-spin
interactions, and derive the ground state phase diagram. A small (or even
infinitesimal) field leads to a new phase that corresponds to a
non-intersecting loop gas on the kagome lattice, with entropy 1.4053... per
unit cell and a mean magnetization for the b-spins of 0.12(1) per site. In
addition, we find that for moderate applied field, there is a critical spin
liquid phase which maps to close-packed dimers on the honeycomb lattice, which
survives even when the a-spins are in the Heisenberg limit.Comment: 12 pages, 12 figure
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