Jackiw-Rebbi fermions in a synthetic topological chain – STOIC

Topological excitations emerge at the interface between phases of matter of different topological classes. As they inherit the mathematical resilience to disorder of their supporting topological phase, they are attractive for building highly coherent quantum bits robust to local disorder. Topological quasi-particles hosted in topologically non-trivial phases usually possess exotic properties underlying new physics, which makes them extremely interesting to investigate for purely fundamental prospects. Currently, the topological excitations most actively sought for are Majorana zero modes which should exhibit a particle/anti-particle duality and non-abelian exchange statistics. Despite years of effort, signatures of their presence in investigated devices remain more than elusive and no topological qubit has been realized de facto. Project STOIC proposes a radical shift in the experimental investigation of topological phases by changing the general approach.
Indeed, a chain whose local site parameters can be individually controlled constitutes the simplest system in which a topological phase can emerge. The modulation of the tunnel coupling in a 1D conductor emulates the SSH model where Jackiw-Rebbi fermions having a fractional charge and non-abelian exchange statistics should emerge. Project STOIC proposes to realize Jackiw-Rebbi fractional modes in an ultra-clean carbon nanotube, the closest to an ideal 1D conductor, deposited over an array of gate electrodes that can locally control the hopping term between neighbouring sites. The fractional charge will be measured by exploiting the capacitive coupling to a microwave cavity in a cQED architecture to reveal the existence of Jackiw-Rebbi fermions. Project STOIC will open a new route to the investigation of topological phases.