Dynamics of non-equilibrium states in correlated electron systems with broken symmetry

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Pump-Probe experiments, where the time evolution of a system can be studied after a short excitation pulse, have been recently also applied to materials with strong electronic correlations. Such systemsare often characterized by a ground state with charge, spin or (and) orbital order where the translational symmetry and rotational symmetry with respect to spin or (and) orbital states is sponaneouslybroken. Pump-probe experiments allow in principle to study separately the dynamics of charge, spin and orbital degrees of freedom. Within the proposed project it is planned to investigate thetime evolution of electronically inhomogeneous and correlated states starting from an non-equilibrium situation, i.e. after pumping. Methodically the project is based on the time-dependent Gutzwillerapproach which represents a very good approximation for the calculation of the dynamics of correlated systems. Moreover the method has the advantage that it can handle sufficiently largesystems and it has already been succesfully applied to the calculation of ground state properties of symmetry broken states. Aim of the project is the investigation of the dynamics of coupled spin- andcharge density waves which have been observed in nickelates, cuprates and manganites. In collaboration with the group of Prof. Carbone (Lausanne) it is planned to analyze experimental data fortime-dependent optical properties of high-Tc cuprates.In this regard the project also intends to clarify the role of different relaxation mechanisms on the dynamics of spin and charge degrees of freedom.