More on Q-kinks: a (1+1)-dimensional analogue of dyons

Time-dependent solutions, called Q-kinks, of certain (1+1)-dimensional sigma-models with scalar potentials are shown to have many properties in common with BPS dyons of (3+1)-dimensional Yang-Mills/Higgs theory. In particular, sigma-model analogues of the phenomena of fractionally charged dyons and of charge-exchange between dyons and axion domain walls are described. In 2+1 dimensions Q-kinks become Q-strings. We show that the recently discovered Q-lumps of the (2+1)-dimensional model can be considered to be stable loops of Q-string.