We study third-harmonic generation (THG) in an excitonic insulator (EI) described a two-band correlated electron model. Employing the perturbative expansion with respect to external electric field, we derive THG susceptibility taking into account collective dynamics of order parameter. In inversion-symmetric EI, parameter motion is activated at second field and its effects arise THG. find three...

There have been two competing paradigms in artificial intelligence (AI) development ever since its birth 1956, i.e., symbolism and connectionism (or sub-symbolism). While dominated AI research by the end of 1980s, gained momentum 1990s is gradually displacing symbolism. This paper considers as first generation second generation. However, each these simulates human mind from only one perspective...