The space-time symmetry of noncommutative quantum field theories with a deformed quantization is described by the twisted Poincaré algebra, while that of standard commutative quantum field theories is described by the Poincaré algebra. Based on the equivalence of the deformed theory with a commutative field theory, the correspondence between the twisted Poincaré symmetry of the deformed theory ...

In front-form dynamics the current operator can be constructed from auxiliary operators, defined in a Breit frame where initial and final three-momenta of the system are directed along the z axis. Poincaré covariance constraints reduce for auxiliary operators to the ones imposed only by kinematical rotations around the z axis. Elastic and transition form factors can be extracted without any amb...

Individual spinors in a SU(2) spin network are described by their relations to the background spin network. A 'covariant' formulation of these relations yields the de Sitter group SO(3,2) as the fundamental symmetry group. Locally this symmetry group is approximated by the Poincaré group, which leaves invariant (certain) clusters of spinors. The calculated masses of these clusters reproduce the...

Biped robots form a subclass of legged or walking robots. The study of mechanical legged motion has been motivated by its potential use as a means of locomotion in rough terrain, as well as its potential benefits to prothesis development and testing. This paper concentrates on issues related to the automatic control of biped robots. More precisely, its primary goal is to contribute a means to p...

There are numerous non-smooth factors in railway vehicle systems, such as flange impact, dry friction, creep force, and so on. Such heavily affect the dynamical behavior of systems. In this paper, we investigate mathematically analyze double grazing bifurcations wheelset systems with contact. Two types models impact considered, one is a rigid model other soft model. First, derive Poincaré maps ...

Based on the d’Alembert-Lagrange-Poincaré variational principle, we formulate general equations of motion for mechanical systems subject to nonlinear nonholonomic constraints, that do not involve Lagrangian undetermined multipliers. We write these equations in a canonical form called the Poincaré-Hamilton equations, and study a version of corresponding Poincaré-Cartan integral invariant which a...

Individual spinors in a SU(2) spin network are described by their relations to the background spin network. A 'covariant' formulation of these relations yields the de Sitter group SO(3,2) as the fundamental symmetry group. Locally this symmetry group is approximated by the Poincaré group, which leaves invariant (certain) clusters of spinors. The calculated masses of these clusters reproduce the...