0000000000643335
AUTHOR
J. Niederle
Contractions yielding new supersymmetric extensions of the poincaré algebra
Two new Poincare superalgebras are analysed. They are obtained by the Wigner-Inonu contraction from two real forms of the superalgebra OSp(2;4;C) - one describing the N = 2 anti-de-Sitter superalgebra with a non-compact internal symmetry SO(1, 1) and the other corresponding to the de-Sitter superalgebra with internal symmetry SO(2). Both are 19-dimensional self-conjugate extensions of the Konopel'chenko superalgebra. They contain 10 Poincare generators and one generator of internal symmetry in addition to 8 odd generators half of which, however, do not commute with translations.
Infinite sets of conservation laws for linear and nonlinear field equations
The relation between an infinite set of conservation laws of a linear field equation and the enveloping algebra of the space-time symmetry group is established. It is shown that each symmetric element of the enveloping algebra of the space-time symmetry group of a linear field equation generates a one-parameter group of symmetries of the field equation. The cases of the Maxwell and Dirac equations are studied in detail. Then it is shown that (at least in the sense of a power series in the ‘coupling constant’) the conservation laws of the linear case can be deformed to conservation laws of a nonlinear field equation which is obtained from the linear one by adding a nonlinear term invariant u…