1,672 research outputs found
Zero-curvature condition in two dimensions. Relativistic particle models and finite \W-transformations
A relation between an gauge particle model and the zero-curvature
condition in a two-dimensional gauge theory is presented. For the case
we construct finite \W-transformations.Comment: 14 pages, UTTG-04-9
Particle Mechanics Models with W-symmetries
We introduce a particle mechanics model with Sp() gauge invariance.
Different partial gauge-fixings by means of sl(2) embeddings on the gauge
algebra lead to reduced models which are invariant under diffeomorphisms and
classical non-linear \W-transformations as the residual gauge symmetries thus
providing a set of models of gauge and matter fields coupled in a \W-invariant
way. The equations of motion for the matter variables give Lax operators in a
matrix form. We examine several examples in detail and discuss the issue of
integration of infinitesimal \W-transformations.Comment: 34 pages, LaTeX, no figures. Several changes (including Title) and
new material added. Version to appear in Ann. Phy
On the possibility of generating a 4-neutron resonance with a {\boldmath } isospin 3-neutron force
We consider the theoretical possibility to generate a narrow resonance in the
four neutron system as suggested by a recent experimental result. To that end,
a phenomenological three neutron force is introduced, in addition to a
realistic interaction. We inquire what should be the strength of the
force in order to generate such a resonance. The reliability of the
three-neutron force in the channel is exmined, by analyzing its
consistency with the low-lying states of H, He and Li and the
scattering.
The {\it ab initio} solution of the Schr\"{o}dinger equation is obtained
using the complex scaling method with boundary conditions appropiate to the
four-body resonances. We find that in order to generate narrow resonant
states a remarkably attractive force in the channel is required.Comment: 11 pages, 11 figures, minor change, published version, to be
published in Physical Review
Horizontal transfer between loose compartments stabilizes replication of fragmented ribozymes
The emergence of replicases that can replicate themselves is a central issue
in the origin of life. Recent experiments suggest that such replicases can be
realized if an RNA polymerase ribozyme is divided into fragments short enough
to be replicable by the ribozyme and if these fragments self-assemble into a
functional ribozyme. However, the continued self-replication of such replicases
requires that the production of every essential fragment be balanced and
sustained. Here, we use mathematical modeling to investigate whether and under
what conditions fragmented replicases achieve continued self-replication. We
first show that under a simple batch condition, the replicases fail to display
continued self-replication owing to positive feedback inherent in these
replicases. This positive feedback inevitably biases replication toward a
subset of fragments, so that the replicases eventually fail to sustain the
production of all essential fragments. We then show that this inherent
instability can be resolved by small rates of random content exchange between
loose compartments (i.e., horizontal transfer). In this case, the balanced
production of all fragments is achieved through negative frequency-dependent
selection operating in the population dynamics of compartments. This selection
mechanism arises from an interaction mediated by horizontal transfer between
intracellular and intercellular symmetry breaking. The horizontal transfer also
ensures the presence of all essential fragments in each compartment, sustaining
self-replication. Taken together, our results underline compartmentalization
and horizontal transfer in the origin of the first self-replicating replicases.Comment: 14 pages, 4 figures, and supplemental materia
Brane Dualities in Non-relativistic Limit
We analyze brane dualities in the non-relativistic limit of the worldvolume
actions. In particular we have analyzed how the non-relativistic M2-brane is
related via these dualities to non-relativistic D2-brane, non-relativistic IIA
fundamental string and also, by using T-duality, to non-relativistic D1-string.
These actions coincide with ones obtained from relativistic actions by taking
non-relativistic limit, showing that the non-relativistic limit and the
dualities commute in these cases.Comment: 21 pages, 1 figur
Space-time Vector Supersymmetry and Massive Spinning Particle
We construct the action of a relativistic spinning particle from a non-linear
realization of a space-time odd vector extension of the Poincar\'e group. For
particular values of the parameters appearing in the lagrangian the model has a
gauge world-line supersymmetry.{As a consequence of this local symmetry there
are BPS solutions in the model preserving 1/5 of the supersymmetries.} A
supersymmetric invariant quantization produces two decoupled 4d Dirac
equations.Comment: 14 pages. Few references and two comments adde
W, Linear and Non-local \W-Algebras in Sp(4) Particle Model
We comment on relations between the linear W_{2,4}^{linear} algebra and
non-linear W(2,4)$ algebra appearing in a Sp(4) particle mechanics model by
using Lax equations. The appearance of the non-local V_{2,2} algebra is also
studied.Comment: 10 pages, late
Relay Backpropagation for Effective Learning of Deep Convolutional Neural Networks
Learning deeper convolutional neural networks becomes a tendency in recent
years. However, many empirical evidences suggest that performance improvement
cannot be gained by simply stacking more layers. In this paper, we consider the
issue from an information theoretical perspective, and propose a novel method
Relay Backpropagation, that encourages the propagation of effective information
through the network in training stage. By virtue of the method, we achieved the
first place in ILSVRC 2015 Scene Classification Challenge. Extensive
experiments on two challenging large scale datasets demonstrate the
effectiveness of our method is not restricted to a specific dataset or network
architecture. Our models will be available to the research community later.Comment: Technical report for our submissions to the ILSVRC 2015 Scene
Classification Challenge, where we won the first plac
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