Several Approaches to Realistic Dynamical Simulations in Advanced Materials

This talk will cover several methods for realistic dynamical simulations of advanced materials, including ultrafast phase transitions. In our first method, Ginzburg-Landau-like order parameters are coupled to one another and to the vector potential of an incoming laser pulse, so that the resulting phase transition is described by time-dependent Ginzburg-Landau theory. This approach is capable of describing one mechanism which is observed in light-induced superconductivity. Secondly, a new method will be introduced for treating ultrafast phase transitions, such as those involving superconductivity, magnetism, charge density waves, and spin density waves. Illustrative results will be presented for a toy model, with the electronic temperature immediately after the laser pulse calculated as a function of the fluence. Finally, we modify this approach with the addition of an electronic self-energy, which allows for calculations currently not possible with conventional density-functional-based methods.