Low-Dimensional Long-Range Topological Charge Structure in the QCD Vacuum

While sign-coherent 4-dimensional structures cannot dominate topological charge fluctuations in the QCD vacuum at all scales due to reflection positivity, it is possible that enhanced coherence exists over extended space-time regions of lower dimension. Using the overlap Dirac operator to calculate topological charge density, we present evidence for such structure in pure-glue SU(3) lattice gauge theory. It is found that a typical equilibrium configuration is dominated by two oppositely-charged sign-coherent connected structures (``sheets'') covering about 80% of space-time. Each sheet is built from elementary 3-d cubes connected through 2-d faces, and approximates a low-dimensional curved manifold (or possibly a fractal structure) embedded in the 4-d space. At the heart of the sheet is a ``skeleton'' formed by about 18% of the most intense space-time points organized into a global long-range structure, involving connected parts spreading over maximal possible distances. We find that the skeleton is locally 1-dimensional and propose that its geometrical properties might be relevant for understanding the possible role of topological charge fluctuations in the physics of chiral symmetry breaking.Comment: 4 pages RevTeX, 4 figures; v2: 6 pages, 5 figures, more explanations provided, figure and references added, published versio

Improved chiral properties of FLIC fermions

Copyright © 2005 Elsevier B.V. All rights reserved.The chiral properties of the fat-link irrelevant clover (FLIC) fermion action are examined. The improved chiral properties of fermion actions incorporating smoothed links are realised in the FLIC action where only the irrelevant operators of the fermion action are constructed with smoothed links. In particular, the histogram of the additive mass renormalisation encountered in chiral-symmetry breaking Wilson-type fermion actions is seen to narrow upon introducing fat links in the irrelevant operators. The exceptional configuration problem of quenched QCD is reduced, enabling access to the light quark mass regime of mπ/mρ≃1/3. In particular, quenched chiral nonanalytic behaviour is revealed in the light quark mass dependence of the Δ-baryon mass. FLIC fermions offer a promising approach to revealing the properties of full QCD at light quark masses. © 2005 Elsevier B.V. All rights reserved.S. Boinepalli, W. Kamleh, D.B. Leinweber, A.G. Williams and J.M. Zanottihttp://www.elsevier.com/wps/find/journaldescription.cws_home/505706/description#descriptio

Text Invader: A Graphic Interference on Semantic Flow

In this paper we report on a system of typographic intervention which aims to bring about a typesetting environment which automates the aesthetic as well as contextual concerns previously manifested in the output of deconstructivist typographers throughout the 20th century. While in the current state of the undertaking a commercial font design software named FontLab has been used to bring about a virus which substitutes vectors for semantic patterns found in bodies of text, future work will evolve towards the creation of a standalone application which may aid in a convergence of the fields of textual authorship and graphic design

Hydroxyl Radical Imaging at kHz Rates Using a Frequency-Quadrupled Nd:YLF Laser

Laser-induced fluorescence imaging of hydroxyl radicals has been an important tool in combustion research for more than twenty years. More recently, high frame rate imaging of hydroxyl radicals has been demonstrated using Nd:YAG-pumped dye laser systems. This work describes how a high repetition rate frequency-quadrupled Nd:YLF laser emitting at 263 nm can be used for laser-induced fluorescence imaging of hydroxyl radicals with less complexity. Hydroxyl radicals are excited in the A–X (2,0) band and redshifted fluorescence emission is detected with an image intensified CMOS camera at kHz frame rates. Furthermore, a strategy for high-speed temperature imaging is described.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/86782/1/Sick11.pd