Spontaneous separation of fractional charges discovered

Particles with fractional charges are best known from high energy physics in the form of quarks, but exotic quasiparticles with fractional charge can also be found in many condensed matter systems at much lower energy. However, one common problem in studying the fractional charges is to find them isolated, since they tend to be strongly bound. As a result typically only integral charges are observed.

Researchers at the University of Kaiserslautern have now discovered that this situation changes drastically when sharp boundaries are created on a system of interacting bosons on a Kagome lattice.  Numerical and analytical calculations demonstrate that fractional charges separate spontaneously and accumulate at the edges. This discovery opens new exciting possibilities to observe these exotic excitations directly, e.g. by high resolution pictures in optical lattices.

The study was recently published in the prestigious scienitific journal Physical Review Letters:
Chiral Edge States and Fractional Charge Separation in a System of Interacting Bosons on a Kagome Lattice
Xue-Feng Zhang and Sebastian Eggert
Phys. Rev. Lett. 111, 147201 (2013)

The studies were funded by the ‘‘Allianz fuer Hochleistungsrechnen Rheinland-Pfalz’’, by computer resources at the Institute of Theoretical Physics of the Chinese Academy of Sciences, and by the Deutsche Forschungsgemeinschaft (DFG) via the SFB/Transregio 49.