1,234 research outputs found
Dynamics of Nucleation in the Ising Model
Reactive pathways to nucleation in a three-dimensional Ising model at 60% of
the critical temperature are studied using transition path sampling of single
spin flip Monte Carlo dynamics. Analysis of the transition state ensemble (TSE)
indicates that the critical nuclei are rough and anisotropic. The TSE,
projected onto the free energy surface characterized by cluster size, N, and
surface area, S, indicates the significance of other variables in addition to
these two traditional reaction coordinates for nucleation. The transmission
coefficient along N is ~ 0.35, and this reduction of the transmission
coefficient from unity is explained in terms of the stochastic nature of the
dynamic model.Comment: In press at the Journal of Physical Chemistry B, 7 pages, 8 figure
Swept source optical coherence tomography findings in a severe traumatic maculopathy following firework ocular injury
APENet: LQCD clusters a la APE
Developed by the APE group, APENet is a new high speed, low latency,
3-dimensional interconnect architecture optimized for PC clusters running
LQCD-like numerical applications. The hardware implementation is based on a
single PCI-X 133MHz network interface card hosting six indipendent
bi-directional channels with a peak bandwidth of 676 MB/s each direction. We
discuss preliminary benchmark results showing exciting performances similar or
better than those found in high-end commercial network systems.Comment: Lattice2004(machines), 3 pages, 4 figure
Many-core applications to online track reconstruction in HEP experiments
Interest in parallel architectures applied to real time selections is growing
in High Energy Physics (HEP) experiments. In this paper we describe performance
measurements of Graphic Processing Units (GPUs) and Intel Many Integrated Core
architecture (MIC) when applied to a typical HEP online task: the selection of
events based on the trajectories of charged particles. We use as benchmark a
scaled-up version of the algorithm used at CDF experiment at Tevatron for
online track reconstruction - the SVT algorithm - as a realistic test-case for
low-latency trigger systems using new computing architectures for LHC
experiment. We examine the complexity/performance trade-off in porting existing
serial algorithms to many-core devices. Measurements of both data processing
and data transfer latency are shown, considering different I/O strategies
to/from the parallel devices.Comment: Proceedings for the 20th International Conference on Computing in
High Energy and Nuclear Physics (CHEP); missing acks adde
Vacuum Condensates and Dynamical Mass Generation in Euclidean Yang-Mills Theories
Vacuum condensates of dimension two and their relevance for the dynamical
mass generation for gluons in Yang-Mills theories are discussedComment: Talk given at the International Conference on Color Confinement and
Hadrons in Quantum Chromodynamics, Confinement 2003, TITech and RIKEN, Tokyo,
Japan, July 21-24, 200
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Translation of Anticancer Efficacy From Nonclinical Models to the Clinic
Mouse cancer models have provided critical insights into tumor biology; however, clinical translation of these findings has been challenging. This perspective posits that factors impacting on successful translation start with limitations in capturing human cancer pathophysiology and end with challenges in generating robust translatable preclinical end points. A comprehensive approach that considers clinically relevant mouse models with both an integrated biomarker strategy and a complementary modeling and simulation effort will strengthen the current oncology drug development paradigm
Status of the APENet project
Comment: 6 pages, 5 figures, poster presented at Lattice 2005 (Algorithms and Machines), Dublin, July 25-3
Finite-top-mass effects in NNLO Higgs production
We construct an accurate approximation to the exact NNLO cross section for
Higgs production in gluon-gluon fusion by matching the dominant finite top mass
corrections recently computed by us to the known result in the infinite mass
limit. The ensuing corrections to the partonic cross section are very large
when the center of mass energy of the partonic collision is much larger than
the Higgs mass, but lead to a moderate correction at the percent level to the
total Higgs production cross section at the LHC. Our computation thus reduces
the uncertainty related to these corrections at the LHC from the percent to the
per mille level.Comment: 4 pages, 4 figures; to be published in the proceedings of QCD2008.
Reference adde
High-speed data transfer with FPGAs and QSFP+ modules
We present test results and characterization of a data transmission system
based on a last generation FPGA and a commercial QSFP+ (Quad Small Form
Pluggable +) module. QSFP+ standard defines a hot-pluggable transceiver
available in copper or optical cable assemblies for an aggregated bandwidth of
up to 40 Gbps. We implemented a complete testbench based on a commercial
development card mounting an Altera Stratix IV FPGA with 24 serial transceivers
at 8.5 Gbps, together with a custom mezzanine hosting three QSFP+ modules. We
present test results and signal integrity measurements up to an aggregated
bandwidth of 12 Gbps.Comment: 5 pages, 3 figures, Published on JINST Journal of Instrumentation
proceedings of Topical Workshop on Electronics for Particle Physics 2010,
20-24 September 2010, Aachen, Germany(R Ammendola et al 2010 JINST 5 C12019
More on ghost condensation in Yang-Mills theory: BCS versus Overhauser effect and the breakdown of the Nakanishi-Ojima annex SL(2,R) symmetry
We analyze the ghost condensates ,
and in Yang-Mills theory in the Curci-Ferrari gauge. By
combining the local composite operator formalism with the algebraic
renormalization technique, we are able to give a simultaneous discussion of
, and , which
can be seen as playing the role of the BCS, respectively Overhauser effect in
ordinary superconductivity. The Curci-Ferrari gauge exhibits a global
continuous symmetry generated by the Nakanishi-Ojima (NO) algebra. This algebra
includes, next to the (anti-)BRST transformation, a SL(2,R) subalgebra. We
discuss the dynamical symmetry breaking of the NO algebra through these ghost
condensates. Particular attention is paid to the Landau gauge, a special case
of the Curci-Ferrari gauge.Comment: 33 pages, 2 eps figures. v2: version published in JHEP, author added,
error in potential corrected. Results and conclusions unchange
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