11,926 research outputs found
The Topology of Dislocations in Smectic Liquid Crystals
The order parameter of the smectic liquid crystal phase is the same as that
of a superfluid or superconductor, namely a complex scalar field. We show that
the essential difference in boundary conditions between these systems leads to
a markedly different topological structure of the defects. Screw and edge
defects can be distinguished topologically. This implies an invariant on an
edge dislocation loop so that smectic defects can be topologically linked not
unlike defects in ordered systems with non-Abelian fundamental groups.Comment: 11 pages, many figures, the full catastrophe. Supplementary data with
two movies can be found at
http://iopscience.iop.org/article/10.1088/1367-2630/18/5/05301
Discretizing Gravity in Warped Spacetime
We investigate the discretized version of the compact Randall-Sundrum model.
By studying the mass eigenstates of the lattice theory, we demonstrate that for
warped space, unlike for flat space, the strong coupling scale does not depend
on the IR scale and lattice size. However, strong coupling does prevent us from
taking the continuum limit of the lattice theory. Nonetheless, the lattice
theory works in the manifestly holographic regime and successfully reproduces
the most significant features of the warped theory. It is even in some respects
better than the KK theory, which must be carefully regulated to obtain the
correct physical results. Because it is easier to construct lattice theories
than to find exact solutions to GR, we expect lattice gravity to be a useful
tool for exploring field theory in curved space.Comment: 17 pages, 4 figures; references adde
Thermal storage experience at the MSSTF and plans for the future
The background of thermal storage development at the Midtemperature Solar Systems Test Facility is reviewed. The problems which were encountered are discussed and a course of action for resolving the problems is outlined. Scaling effects of going from laboratory models to full-size applications were determined and applied to thermal storage needs in near-term solar projects
Single-Calf Heifer System Profitability Compared to Other North Dakota Beef Production Systems
Production Economics, Productivity Analysis,
Straight Round the Twist: Frustration and Chirality in Smectics-A
Frustration is a powerful mechanism in condensed matter systems, driving both
order and co plexity. In smectics, the frustration between macroscopic
chirality and equally spaced layers generates textures characterised by a
proliferation of defects. In this article, we study several different ground
states of the chiral Landau-de Gennes free energy for a smectic liquid crystal.
The standard theory finds the twist grain boundary (TGB) phase to be the ground
state for chiral type II smectics. However, for very highly chiral systems, the
hierarchical helical nanofilament (HN) phase can form and is stable over the
TGB.Comment: 9 pages, 3 figures, submitted to J. Interface Focu
Localization of Bulk Form Fields on Dilatonic Domain Walls
We study the localization properties of bulk form potentials on dilatonic
domain walls. We find that bulk form potentials of any ranks can be localized
as form potentials of the same ranks or one lower ranks, for any values of the
dilaton coupling parameter. For large enough values of the dilaton coupling
parameter, bulk form potentials of any ranks can be localized as form
potentials of both the same ranks and one lower ranks.Comment: 9 pages, LaTeX, reference adde
OPEN ACCESS AND MISSING MARKETS IN ARTISANAL FISHING
This paper combines a model of open access fisheries exploitation with a distance-based approach to missing labor and product markets. The model generates predictions about the circumstances under which exploitation increases or decreases with distance. An econometric model is estimated with survey data from artisanal fishing households in Minahasa, Indonesia. The results can be used to assess the impacts of improved transportation infrastructure on fishery exploitation.Marketing,
Chirality in Liquid Crystals: from Microscopic Origins to Macroscopic Structure
Molecular chirality leads to a wonderful variety of equilibrium structures,
from the simple cholesteric phase to the twist-grain-boundary phases, and it is
responsible for interesting and technologically important materials like
ferroelectric liquid crystals. This paper will review some recent advances in
our understanding of the connection between the chiral geometry of individual
molecules and the important phenomenological parameters that determine
macroscopic chiral structure. It will then consider chiral structure in
columnar systems and propose a new equilibrium phase consisting of a regular
lattice of twisted ropes.Comment: 20 pages with 6 epsf figure
Bulk versus brane running couplings
A simplified higher dimensional Randall-Sundrum-like model in 6 dimensions is
considered. It has been observed previously by Goldberger and Wise that in such
a self-interacting scalar theory on the bulk with a conical singularity there
is mixing of renormalization of 4d brane couplings with that of the bulk
couplings. We study the influence of the running bulk couplings on the running
of the 4d brane couplings. We find that bulk quantum effects may completely
alter the running of brane couplings. In particular, the structure of the
Landau pole may be drastically altered and non-asymptotically free running may
turn into asymptotically safe (or free) behavior.Comment: 11 pages, no figures, REVTeX
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