Combined Defects in Ferroelectric Nematics

A very important and influential idea of the so-called combined topological defects was proposed for the first time in cosmology (see, for example, the fundamental work [1]) to describe the emergence of various topological defects in the early stages of the evolution of the universe. This idea was later developed in detail theoretically and confirmed by sophisticated experiments in superfluid helium-3 carried out by a group of researchers from the Low Temperature Laboratory in Helsinki, the Kapitsa Institute for Physical Problems and the Landau Institute for Theoretical Physics, Russian Academy of Sciences. In the present publication, which is motivated precisely by these studies, the possibility of such combined defects is illustrated using a much less exotic example of liquid crystals.