The Experts below are selected from a list of 309 Experts worldwide ranked by ideXlab platform
Cedric Troessaert - One of the best experts on this subject based on the ideXlab platform.
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asymptotic structure of a massless scalar field and its dual two form field at spatial Infinity
arXiv: High Energy Physics - Theory, 2018Co-Authors: Marc Henneaux, Cedric TroessaertAbstract:Relativistic field theories with a power law decay in $r^{-k}$ at spatial Infinity generically possess an infinite number of conserved quantities because of Lorentz invariance. Most of these are not related in any obvious way to symmetry transformations of which they would be the Noether charges. We discuss the issue in the case of a massless scalar field. By going to the dual formulation in terms of a $2$-form (as was done recently in a null Infinity analysis), we relate some of the scalar charges to symmetry transformations acting on the $2$-form and on surface degrees of freedom that must be added at spatial Infinity. These new degrees of freedom are necessary to get a consistent relativistic description in the dual picture, since boosts would otherwise fail to be canonical transformations. We provide explicit boundary conditions on the $2$-form and its conjugate momentum, which involves parity conditions with a twist, as in the case of electromagnetism and gravity. The symmetry group at spatial Infinity is composed of `improper gauge transformations'. It is abelian and infinite-dimensional. We also briefly discuss the realization of the asymptotic symmetries, characterized by a non trivial central extension and point out vacuum degeneracy.
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Asymptotic symmetries of electromagnetism at spatial Infinity
Journal of High Energy Physics, 2018Co-Authors: Marc Henneaux, Cedric TroessaertAbstract:We analyse the asymptotic symmetries of Maxwell theory at spatial Infinity through the Hamiltonian formalism. Precise, consistent boundary conditions are explicitly given and shown to be invariant under asymptotic angle-dependent u(1)-gauge transformations. These symmetries generically have non-vanishing charges. The algebra of the canonical generators of this infinite-dimensional symmetry with the Poincare charges is computed. The treatment requires the addition of surface degrees of freedom at Infinity and a modification of the standard symplectic form by surface terms. We extend the general formulation of well-defined generators and Hamiltonian vector fields to encompass such boundary modifications of the symplectic structure. Our study covers magnetic monopoles.
Philippe Michel - One of the best experts on this subject based on the ideXlab platform.
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brief on a sufficient transversality condition for infinite horizon optimal control problems
Automatica, 2003Co-Authors: Pierre Cartigny, Philippe MichelAbstract:We prove that, for a class of optimal control problems with infinite horizon, convergence to zero for the co-state variable when time goes to Infinity is a sufficient transversality condition.
Marc Henneaux - One of the best experts on this subject based on the ideXlab platform.
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asymptotic structure of a massless scalar field and its dual two form field at spatial Infinity
arXiv: High Energy Physics - Theory, 2018Co-Authors: Marc Henneaux, Cedric TroessaertAbstract:Relativistic field theories with a power law decay in $r^{-k}$ at spatial Infinity generically possess an infinite number of conserved quantities because of Lorentz invariance. Most of these are not related in any obvious way to symmetry transformations of which they would be the Noether charges. We discuss the issue in the case of a massless scalar field. By going to the dual formulation in terms of a $2$-form (as was done recently in a null Infinity analysis), we relate some of the scalar charges to symmetry transformations acting on the $2$-form and on surface degrees of freedom that must be added at spatial Infinity. These new degrees of freedom are necessary to get a consistent relativistic description in the dual picture, since boosts would otherwise fail to be canonical transformations. We provide explicit boundary conditions on the $2$-form and its conjugate momentum, which involves parity conditions with a twist, as in the case of electromagnetism and gravity. The symmetry group at spatial Infinity is composed of `improper gauge transformations'. It is abelian and infinite-dimensional. We also briefly discuss the realization of the asymptotic symmetries, characterized by a non trivial central extension and point out vacuum degeneracy.
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Asymptotic symmetries of electromagnetism at spatial Infinity
Journal of High Energy Physics, 2018Co-Authors: Marc Henneaux, Cedric TroessaertAbstract:We analyse the asymptotic symmetries of Maxwell theory at spatial Infinity through the Hamiltonian formalism. Precise, consistent boundary conditions are explicitly given and shown to be invariant under asymptotic angle-dependent u(1)-gauge transformations. These symmetries generically have non-vanishing charges. The algebra of the canonical generators of this infinite-dimensional symmetry with the Poincare charges is computed. The treatment requires the addition of surface degrees of freedom at Infinity and a modification of the standard symplectic form by surface terms. We extend the general formulation of well-defined generators and Hamiltonian vector fields to encompass such boundary modifications of the symplectic structure. Our study covers magnetic monopoles.
Milan Batista - One of the best experts on this subject based on the ideXlab platform.
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on the stress concentration around a hole in an infinite plate subject to a uniform load at Infinity
International Journal of Mechanical Sciences, 2011Co-Authors: Milan BatistaAbstract:Abstract In this paper stress concentration around a hole in an infinite plate that is subjected to a uniform load at Infinity is considered. The stress is calculated by using a modified Muskhelishvili complex variable method. The method is illustrated by several examples of stress distribution around polygonal holes of a complex geometry utilizing the Schwartz–Chistoffel mapping function.
Pierre Cartigny - One of the best experts on this subject based on the ideXlab platform.
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brief on a sufficient transversality condition for infinite horizon optimal control problems
Automatica, 2003Co-Authors: Pierre Cartigny, Philippe MichelAbstract:We prove that, for a class of optimal control problems with infinite horizon, convergence to zero for the co-state variable when time goes to Infinity is a sufficient transversality condition.
