15,992 research outputs found
Topologically Massive Gauge Theories and their Dual Factorised Gauge Invariant Formulation
There exists a well-known duality between the Maxwell-Chern-Simons theory and
the self-dual massive model in 2+1 dimensions. This dual description has been
extended to topologically massive gauge theories (TMGT) in any dimension. This
Letter introduces an unconventional approach to the construction of this type
of duality through a reparametrisation of the master theory action. The dual
action thereby obtained preserves the same gauge symmetry structure as the
original theory. Furthermore, the dual action is factorised into a propagating
sector of massive gauge invariant variables and a sector with gauge variant
variables defining a pure topological field theory. Combining results obtained
within the Lagrangian and Hamiltonian formulations, a new completed structure
for a gauge invariant dual factorisation of TMGT is thus achieved.Comment: 1+7 pages, no figure
On the Integrability of Supersymmetric Versions of the Structural Equations for Conformally Parametrized Surfaces
The paper presents the bosonic and fermionic supersymmetric extensions of the
structural equations describing conformally parametrized surfaces immersed in a
Grasmann superspace, based on the authors' earlier results. A detailed analysis
of the symmetry properties of both the classical and supersymmetric versions of
the Gauss-Weingarten equations is performed. A supersymmetric generalization of
the conjecture establishing the necessary conditions for a system to be
integrable in the sense of soliton theory is formulated and illustrated by the
examples of supersymmetric versions of the sine-Gordon equation and the
Gauss-Codazzi equations
To sell or not to sell? Behavior of shareholders during price collapses
It is a common belief that the behavior of shareholders depends upon the
direction of price fluctuations: if prices increase they buy, if prices
decrease they sell. That belief, however, is more based on ``common sense''
than on facts. In this paper we present evidence for a specific class of
shareholders which shows that the actual behavior of shareholders can be
markedly different.Comment: 9 pages, 1 figure. To appear in International Journal of Modern
Physics
Individual monitoring of immune responses in rainbow trout after cohabitation and intraperitoneal injection challenge with Yersinia ruckeri
Acknowledgements This work was funded by the National Centre for the Replacement, Refinement and Reduction of Animals in Research (NC3Rs, grant G1100675). The authors are grateful to the aquarium staff at the University of Aberdeen (Karen Massie) and Dr David Smail at Marine Scotland for valuable discussion during the establishment of the experimental design.Peer reviewedPostprin
Utility based cross-layer collaboration for speech enhancement in wireless acoustic sensor networks
A wireless acoustic sensor network is considered that is used to estimate a desired speech signal that has been corrupted by noise. The application layer of the WASN derives an optimal filter in a linear MMSE sense. A utility function is then used in conjunction with the MMSE estimate in order to evaluate the most significant signal components from each node in the system. The utility values are used as a cross-layer link between the application layer and the network layer so the nodes transmit the signal components that are deemed most relevant to the estimate while adhering to the power constraints of the system. The simulation results show that a high signal-to-error and signal-to-noise ratio is still achievable while transmitting a subset of signal components
Invariance quantum groups of the deformed oscillator algebra
A differential calculus is set up on a deformation of the oscillator algebra.
It is uniquely determined by the requirement of invariance under a
seven-dimensional quantum group. The quantum space and its associated
differential calculus are also shown to be invariant under a nine generator
quantum group containing the previous one.Comment: 13 pages, Late
Influence of electromagnetic interferences on the gravimetric sensitivity of surface acoustic waveguides
Surface acoustic waveguides are increasing in interest for (bio)chemical
detection. The surface mass modification leads to measurable changes in the
propagation properties of the waveguide. Among a wide variety of waveguides,
Love mode has been investigated because of its high gravimetric sensitivity.
The acoustic signal launched and detected in the waveguide by electrical
transducers is accompanied by an electromagnetic wave; the interaction of the
two signals, easily enhanced by the open structure of the sensor, creates
interference patterns in the transfer function of the sensor. The influence of
these interferences on the gravimetric sensitivity is presented, whereby the
structure of the entire sensor is modelled. We show that electromagnetic
interferences generate an error in the experimental value of the sensitivity.
This error is different for the open and the closed loop configurations of the
sensor. The theoretical approach is completed by the experimentation of an
actual Love mode sensor operated under liquid in open loop configuration. The
experiment indicates that the interaction depends on the frequency and the mass
modifications.Comment: 28 pages, 8 figure
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