| Autor: |
González-Cuadra D; ICFO-Institut de Ciències Fotòniques, The Barcelona Institute of Science and Technology, Avinguda Carl Friedrich Gauss 3, 08860 Castelldefels (Barcelona), Spain., Dauphin A; ICFO-Institut de Ciències Fotòniques, The Barcelona Institute of Science and Technology, Avinguda Carl Friedrich Gauss 3, 08860 Castelldefels (Barcelona), Spain., Grzybowski PR; Faculty of Physics, Adam Mickiewicz University, Umultowska 85, 61-614 Poznań, Poland., Lewenstein M; ICFO-Institut de Ciències Fotòniques, The Barcelona Institute of Science and Technology, Avinguda Carl Friedrich Gauss 3, 08860 Castelldefels (Barcelona), Spain.; ICREA, Lluis Companys 23, 08010 Barcelona, Spain., Bermudez A; Departamento de Física Teórica, Universidad Complutense, 28040 Madrid, Spain. |
| Abstrakt: |
We study the Z_{2} Bose-Hubbard model, a chain of interacting bosons the tunneling of which is dressed by a dynamical Z_{2} field. The interplay between spontaneous symmetry breaking (SSB) and topological symmetry protection gives rise to interesting fractional topological phenomena when the system is doped to certain incommensurate fillings. In particular, we hereby show how topological defects in the Z_{2} field can appear in the ground state, connecting different SSB sectors. These defects are dynamical and can travel through the lattice carrying both a topological charge and a fractional particle number. In the hardcore limit, this phenomenon can be understood through a bulk-defect correspondence. Using a pumping argument, we show that it survives also for finite interactions, demonstrating how boson fractionalization induced by topological defects can occur in strongly correlated bosonic systems. Our results indicate the possibility of observing this phenomenon, which appears for fermionic matter in solid-state and high-energy physics, using ultracold atomic systems. |
