22,323 research outputs found
A grammar for a text based music scoring program
The grammar for a text-based music scoring software package and a short example is presented. The computer program developed using this language (available from the author's website) will form the basis for future research into a variety of different input methods for creating music scores
The Non-Equilibrium Reliability of Quantum Memories
The ability to store quantum information without recourse to constant
feedback processes would yield a significant advantage for future
implementations of quantum information processing. In this paper, limitations
of the prototypical model, the Toric code in two dimensions, are elucidated
along with a sufficient condition for overcoming these limitations.
Specifically, the interplay between Hamiltonian perturbations and dynamically
occurring noise is considered as a system in its ground state is brought into
contact with a thermal reservoir. This proves that when utilizing the Toric
code on N^2 qubits in a 2D lattice as a quantum memory, the information cannot
be stored for a time O(N). In contrast, the 2D Ising model protects classical
information against the described noise model for exponentially long times. The
results also have implications for the robustness of braiding operations in
topological quantum computation.Comment: 4 pages. v3: published versio
Using Interactive 3D Software to Create Manipulatable Human Figures for Body Perception Research
The poster presents the use of the DAZ3D program as a measurement tool for body size perception. When studying body schema, researchers often rely on human figure comparisons to examine body size perceptions. Often these figures are two-dimensional drawings or photos of human bodies. However, human bodies are three-dimensional. Previous research has shown the advantage of using three-dimensional changeable figures in assessing body size perception (Crossley, Cornelissen, & Tovee, 2012). We chose the DAZ3D program over other options (e.g., Body Visualizer) because it allows the user to rotate the figure in space (both depth and plane), convert manipulated figure measures to real life metrics (e.g., inches or centimeters), input real life metrics to create figures, and manipulate over 50 parameters of measurement consisting of both length and circumference. The downside to DAZ3D is that it can be confusing to set up and use. We explain how to use DAZ3D software effectively for use in body size perception research. We had participants use the DAZ3D software to represent their own body, allowing them to manipulate 17 body measurements. Our data suggests that participants can easily use the program and accurately represent their body size (their figure was compared to real life body measurements). Additionally, because DAZ3D has the ability to manipulate almost all aspects of the human figure (including parameters such as muscle mass), researchers will be able to make a more fine-grained analysis of distortions in body perception in both men and women
Character degree sums in finite nonsolvable groups
Let N be a minimal normal nonabelian subgroup of a finite group G. We will
show that there exists a nontrivial irreducible character of N of degree at
least 5 which is extendible to G. This result will be used to settle two open
questions raised by Berkovich and Mann, and Berkovich and Zhmud'.Comment: 5 page
Quenching of Cross Sections in Nucleon Transfer Reactions
Cross sections for proton knockout observed in (e,e'p) reactions are
apparently quenched by a factor of ~0.5, an effect attributed to short-range
correlations between nucleons. Here we demonstrate that such quenching is not
restricted to proton knockout, but a more general phenomenon associated with
any nucleon transfer. Measurements of absolute cross sections on a number of
targets between 16O and 208Pb were analyzed in a consistent way, with the cross
sections reduced to spectroscopic factors through the distorted-wave Born
approximation with global optical potentials. Across the 124 cases analyzed
here, induced by various proton- and neutron-transfer reactions and with
angular momentum transfer l=0-7, the results are consistent with a quenching
factor of 0.55. This is an apparently uniform quenching of single-particle
motion in the nuclear medium. The effect is seen not only in (d,p) reactions
but also in reactions with A=3 and 4 projectiles, when realistic wave functions
are used for the projectiles.Comment: 5 pages, 3 figures, accepted to Physical Review Letter
The Implications of Ignorance for Quantum Error Correction Thresholds
Quantum error correcting codes have a distance parameter, conveying the
minimum number of single spin errors that could cause error correction to fail.
However, the success thresholds of finite per-qubit error rate that have been
proven for the likes of the Toric code require them to work well beyond this
limit. We argue that without the assumption of being below the distance limit,
the success of error correction is not only contingent on the noise model, but
what the noise model is believed to be. Any discrepancy must adversely affect
the threshold rate, and risks invalidating existing threshold theorems. We
prove that for the 2D Toric code, suitable thresholds still exist by utilising
a mapping to the 2D random bond Ising model.Comment: 8 pages, 2 figures. Title change enforced by journa
Mixed mode pattern in Doublefoot mutant mouse limb - Turing reaction-diffusion model on a growing domain during limb development
It has been suggested that the Turing reaction–diffusion model on a growing domain is applicable during limb development, but experimental evidence for this hypothesis has been lacking. In the present study, we found that in Doublefoot mutant mice, which have supernumerary digits due to overexpansion of the limb bud, thin digits exist in the proximal part of the hand or foot, which sometimes become normal abruptly at the distal part. We found that exactly the same behaviour can be reproduced by numerical simulation of the simplest possible Turing reaction–diffusion model on a growing domain. We analytically showed that this pattern is related to the saturation of activator kinetics in the model. Furthermore, we showed that a number of experimentally observed phenomena in this system can be explained within the context of a Turing reaction–diffusion model. Finally, we make some experimentally testable predictions
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