4,850 research outputs found
Geometric aspects of nonholonomic field theories
A geometric model for nonholonomic Lagrangian field theory is studied. The
multisymplectic approach to such a theory as well as the corresponding Cauchy
formalism are discussed. It is shown that in both formulations, the relevant
equations for the constrained system can be recovered by a suitable projection
of the equations for the underlying free (i.e. unconstrained) Lagrangian
system.Comment: 29 pages; typos remove
Unified formalism for higher-order non-autonomous dynamical systems
This work is devoted to giving a geometric framework for describing
higher-order non-autonomous mechanical systems. The starting point is to extend
the Lagrangian-Hamiltonian unified formalism of Skinner and Rusk for these
kinds of systems, generalizing previous developments for higher-order
autonomous mechanical systems and first-order non-autonomous mechanical
systems. Then, we use this unified formulation to derive the standard
Lagrangian and Hamiltonian formalisms, including the Legendre-Ostrogradsky map
and the Euler-Lagrange and the Hamilton equations, both for regular and
singular systems. As applications of our model, two examples of regular and
singular physical systems are studied.Comment: 43 pp. We have corrected and clarified the statement of Propositions
2 and 3. A remark is added after Proposition
Hamilton-Jacobi Theory in k-Symplectic Field Theories
In this paper we extend the geometric formalism of Hamilton-Jacobi theory for
Mechanics to the case of classical field theories in the k-symplectic
framework
Spectral analysis of Markarian 421 and Markarian 501 with HAWC
The Hight Altitude Water Cherenkov (HAWC) Gamma-Ray Observatory monitors the
gamma-ray sky in the energy range from 100 GeV to 100 TeV and has detected two
very high energy (VHE) blazars: Markarian 421 (Mrk 421) and Markarian 501 (Mrk
501) in 1.5 years of observations. In this work, we present the spectral
analysis above 1 TeV of both sources using a maximum likelihood method and an
artificial neural network as an energy estimator. The main objectives are to
constrain the spectral curvature of Mrk 421 and Mrk 501 at 5 TeV using
the EBL models from Gilmore et al. (2012) and Franceschini et al. (2008).Comment: Presented at the 35th International Cosmic Ray Conference (ICRC2017),
Bexco, Busan, Korea. See arXiv:1708.02572 for all HAWC contribution
Nonholonomic constraints in -symplectic Classical Field Theories
A -symplectic framework for classical field theories subject to
nonholonomic constraints is presented. If the constrained problem is regular
one can construct a projection operator such that the solutions of the
constrained problem are obtained by projecting the solutions of the free
problem. Symmetries for the nonholonomic system are introduced and we show that
for every such symmetry, there exist a nonholonomic momentum equation. The
proposed formalism permits to introduce in a simple way many tools of
nonholonomic mechanics to nonholonomic field theories.Comment: 27 page
NO ANGIOSTRONGYLUS CANTONENSIS (NEMATODA: METASTRONGYLIDAE) OBSERVED IN 108 RATS IN SAN JUAN, P. R.
NO ANGIOSTRONGYLUS CANTONENSIS (NEMATODA: METASTRONGYLIDAE) OBSERVED IN 108 RATS IN SAN JUAN, P. R
Unified formalism for the generalized kth-order Hamilton-Jacobi problem
The geometric formulation of the Hamilton-Jacobi theory enables us to
generalize it to systems of higher-order ordinary differential equations. In
this work we introduce the unified Lagrangian-Hamiltonian formalism for the
geometric Hamilton-Jacobi theory on higher-order autonomous dynamical systems
described by regular Lagrangian functions.Comment: 9pp. Revised version: Minor corrections done. Second part of our
previous work arXiv:1309.2166. arXiv admin note: substantial text overlap
with arXiv:1309.216
A Sadness Bias in Political News Sharing? The Role of Discrete Emotions in the Engagement and Dissemination of Political News on Facebook
Symmetries in Classical Field Theory
The multisymplectic description of Classical Field Theories is revisited,
including its relation with the presymplectic formalism on the space of Cauchy
data. Both descriptions allow us to give a complete scheme of classification of
infinitesimal symmetries, and to obtain the corresponding conservation laws.Comment: 70S05; 70H33; 55R10; 58A2
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