Speaker
Dr
Dirk Schuricht
(Utrecht University, The Netherlands)
Description
Abstract: We study the effect of interactions on Kitaev's toy
model for Majorana wires. We demonstrate that even
though strong repulsive interaction eventually drive the
system into a Mott insulating state the competition
between the (trivial) band-insulator and the (trivial) Mott
insulator leads to an interjacent topological insulating state
for arbitrary strong interactions. We show that the exact
ground states can be obtained analytically even in the
presence of interactions when the chemical potential is
tuned to a particular function of the other parameters. The
ground states obtained are two-fold degenerate and differ in
fermion parity, as is the case with the Kitaev/Majorana
chain in a topological phase. We prove that the ground state
is unique in each fermion parity sector and that there exists
an energy gap. We propose a realisation in an array of
superconducting islands with semiconducting nanowires,
where a capacitive coupling between adjacent islands leads
to an effective interaction between the Majorana modes.
