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Enhanced current noise correlations in a Coulomb-Majorana device
Majorana bound states (MBSs) nested in a topological nanowire are predicted
to manifest nonlocal correlations in the presence of a finite energy splitting
between the MBSs. However, the signal of the nonlocal correlations has not yet
been detected in experiments. A possible reason is that the energy splitting is
too weak and seriously affected by many system parameters. Here we investigate
the charging energy induced nonlocal correlations in a hybrid device of MBSs
and quantum dots. The nanowire that hosts the MBSs is assumed in proximity to a
mesoscopic superconducting island with a finite charging energy. Each end of
the nanowire is coupled to one lead via a quantum dot with resonant levels.
With a floating superconducting island, the devices shows a negative
differential conductance and giant super-Poissonian shot noise, due to the
interplay between the nonlocality of the MBSs and dynamical Coulomb blockade
effect. When the island is strongly coupled to a bulk superconductor, the
current cross correlations at small lead chemical potentials are negative by
tuning the dot energy levels. In contrast, the cross correlation is always
positive in a non-Majorana setup. This difference may provide a signature for
the existence of the MBSs.Comment: 11 pages, 10 figure
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