Weak Measurement Protocols for Majorana Bound State Identification

Physical Review Letters, vol. 124, pp. 096801

Abstract

We propose a continuous weak measurement protocol testing the nonlocality of Majorana bound states through current shot noise correlations. The experimental setup contains a topological superconductor island with three normal-conducting leads weakly coupled to different Majorana states. Putting one lead at finite voltage and measuring the shot noise correlations between the other two (grounded) leads, devices with true Majorana states are distinguished from those without by strong current correlations. The presence of true Majorana states manifests itself in unusually high noise levels or the near absence of noise, depending on the chosen device configuration. Monitoring the noise statistics amounts to a weak continuous measurement of the Majorana qubit and yields information similar to that of a full braiding protocol, but at much lower experimental effort. Our theory can be adapted to different platforms and should allow for the clear identification of Majorana states.

Authors 6

1. J. Manousakis

   University of Copenhagen · University of Cologne

   Affiliation as printed

   Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, DK-2100 Copenhagen, Denmark

   Institut für theoretische Physik, Universität zu Köln, Zülpicher Straße 77, D-50937 Köln, Germany

2. Carolin Wille

   Freie Universität Berlin

   Affiliation as printed

   Dahlem Center for Complex Quantum Systems, Physics Department, Freie Universität Berlin, D-14195 Berlin, Germany

3. Alexander Altland

   University of Cologne

   Affiliation as printed

   Institut für theoretische Physik, Universität zu Köln, Zülpicher Straße 77, D-50937 Köln, Germany

4. Reinhold Egger

   Heinrich Heine University Düsseldorf

   Affiliation as printed

   Institut für Theoretische Physik, Heinrich Heine Universität, D-40225 Düsseldorf, Germany

5. Karsten Flensberg

   University of Copenhagen

   Affiliation as printed

   Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, DK-2100 Copenhagen, Denmark

6. Fabian Hassler Aachen JARA-Institute for Quantum Information

   RWTH Aachen University

   Affiliation as printed

   JARA-Institute for Quantum Information, RWTH Aachen University, D-52056 Aachen, Germany

   JARA–Institute for Quantum Information, RWTH Aachen University, D-52056 Aachen, Germany