Topological defects in mixtures of superconducting condensates with different charges

Abstract

We investigate the topological defects in phenomenological models describing mixtures of charged condensates with commensurate electric charges. Such situations are expected to appear for example in liquid metallic deuterium. This is modeled by a multicomponent Ginzburg-Landau theory where the condensates are coupled to the same gauge field by different coupling constants whose ratio is a rational number. We also briefly discuss the case where electric charges are incommensurate. Flux quantization and finiteness of the energy per unit length dictate that the different condensates have different winding and thus different number of (fractional) vortices. Competing attractive and repulsive interactions lead to molecule-like bound state between fractional vortices. Such bound states have finite energy and carry integer flux quanta. These can be characterized by CP 1 topological invariant that motivates their denomination as skyrmions.

Chemical bonds of two vortex species with a generalized Josephson term and arbitrary charges

“…[8,9]. The case of a two-component superconductor with generic charges has been studied already by Garaud and Babaev [7].…”

Different electronic charges in two-component superconductor by coherent state

“…The electronic charges are expressed by the product of the coupling constants and the electronic charges carried by Cooper pairs. This is the reason leading to the different electronic charges [13]. The ratio of the two coupling constants is just the ratio of the two different electronic charges, which is a rational number.…”

“…In Ref. [13], the authors find that the different condensates carry the different windings and different fractional vortices by using flux quantization and finiteness of the energy per unit length.…”

“…[11,12], the authors call it type 1.5 superconductor. Recently, the different electronic charges carried by the condensates are studied by using of Ginzburg-Landau theory [13]. They assume that the coupling constants in the two-component superconductor are different.…”

Towards an Effective Theory of Skyrmion Crystals

“…These interactions change the symmetry of the system and, as a consequence, the order parameter space from G/H = SO(3)/SO(2) of the BP case to G/H = SO(2) ⊗ SO(2) 15 . This implies that a skyrmion lattice is better described as Abrikosov vortices rather than BP skyrmions (see also [16][17][18] ).…”