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How to send current through a neutral mode

Anton Akhmerov, **Leiden University**
__Abstract:__
We show how a chiral Dirac fermion (a massless electron or hole) can be converted into a pair of neutral chiral Majorana fermions (a particle equal to its own antiparticle). These two types of fermions exist on the metallic surface of a topological insulator, respectively, at a magnetic domain wall and at a magnet-superconductor interface. Interferometry of Majorana fermions is a key operation in topological quantum computation, but the detection is problematic since these particles have no charge. The Dirac-Majorana converter enables electrical detection of the interferometric signal.

__Reference:__ Johan Nilsson, A. R. Akhmerov, and C. W. J. Beenakker, PRL **101**, 120403 (2008)