16,532 research outputs found
Zero-mode contribution to the light-front Hamiltonian of Yukawa type models
Light-front Hamiltonian for Yukawa type models is determined without the
framework of canonical light-front formalism. Special attention is given to the
contribution of zero modes.Comment: 14 pages, Latex, revised version with minor changes, Submitted to
J.Phys.
Gauge Invariant Regularization of Quantum Field Theory on the Light-Front
Gauge invariant regularization of quantum field theory in the framework of
Light-Front (LF) Hamiltonian formalism via introducing a lattice in transverse
coordinates and imposing boundary conditions in LF coordinate for gauge
fields on the interval is considered. The remaining ultraviolet
divergences in the longitudinal momentum are removed by gauge invariant
finite mode regularization. We find that LF canonical formalism for the
introduced regularization does not contain usual most complicated second class
constraints connecting zero and nonzero modes of gauge fields. The described
scheme can be used either for the regularization of conventional gauge theory
or for gauge invariant formulation of effective low-energy models on the LF.
The lack of explicit Lorentz invariance in our approach leads to difficulty
with defining the vacuum state. We discuss this difficulty, particulary, in the
connection with the problem of taking the limit of continuous space.Comment: LaTeX 2.09, 15 pages, Proceedings of "12th V.Fock School of Physics",
St-Petersburg 200
Fuzzy logic control of telerobot manipulators
Telerobot systems for advanced applications will require manipulators with redundant 'degrees of freedom' (DOF) that are capable of adapting manipulator configurations to avoid obstacles while achieving the user specified goal. Conventional methods for control of manipulators (based on solution of the inverse kinematics) cannot be easily extended to these situations. Fuzzy logic control offers a possible solution to these needs. A current research program at SRI developed a fuzzy logic controller for a redundant, 4 DOF, planar manipulator. The manipulator end point trajectory can be specified by either a computer program (robot mode) or by manual input (teleoperator). The approach used expresses end-point error and the location of manipulator joints as fuzzy variables. Joint motions are determined by a fuzzy rule set without requiring solution of the inverse kinematics. Additional rules for sensor data, obstacle avoidance and preferred manipulator configuration, e.g., 'righty' or 'lefty', are easily accommodated. The procedure used to generate the fuzzy rules can be extended to higher DOF systems
Canonical formulation of the embedded theory of gravity equivalent to Einstein's General Relativity
We study the approach in which independent variables describing gravity are
functions of the space-time embedding into a flat space of higher dimension. We
formulate a canonical formalism for such a theory in a form, which requires
imposing additional constraints, which are a part of Einstein's equations. As a
result, we obtain a theory with an eight-parameter gauge symmetry. This theory
becomes equivalent to Einstein's general relativity either after partial gauge
fixing or after rewriting the metric in the form that is invariant under the
additional gauge transformations. We write the action for such a theory.Comment: LaTeX, 17 page
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