In this talk, we present a group-theoretical symmetry analysis for the supersymmetric versions of specific nonlinear equations. Specifically, we consider supersymmetric extensions of the (1 + 1)-dimensional sine-Gordon equation, the (1 + 1)-dimensional sinh-Gordon equation and the following generalized polynomial form of the Klein-Gordon equationIn each case, the supersymmetric version of the equation is constructed on the 4dimensional Grassmannian superspace {(x, t, θ 1 , θ 2 )}. Here, the variables x and t represent the bosonic coordinates of 2-dimensional Minkowski space, while the quantities θ 1 and θ 2 are anticommuting fermionic variables. The bosonic function u(x, t) is replaced by the scalar bosonic superfieldwhere φ and ψ are fermionic-valued fields and F is a bosonic field. The supersymmetric extension is constructed in such a way that it is invariant under a set of supersymmetry transformations (generated by vector fields Q x and Q t ) which link the bosonic independent variables x and t to the fermionic independent variables θ 1 and θ 2 respectively. This is ensured by writing the supersymmetric equation in terms of covariant derivative operators D x and D t which anticommute with the supersymmetry generators Q x and Q t respectively. For each of the supersymmetric equations under consideration, we use a generalization of the method of prolongation in order to determine the Lie superalgebra of symmetries of the equation, and we present a systematic classification of all one-dimensional subalgebras of this resulting Lie superalgebra. The method of symmetry reduction then allows us to derive invariant solutions of the supersymmetric model. Some interpretation of the obtained results is given.
References: 1. A. M. Grundland, A J. Hariton and L. Snobl, J. Phys. A: Math. Theor. 42, 335203 (2009). 2. A. M. Grundland, A J. Hariton and L. Snobl, "Invariant solutions of supersymmetric nonlinear wave equations", in preparation (2010).