Dresden 2014 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 55: Transport: Topological insulators I (organized by TT)

HL 55.7: Talk

Tuesday, April 1, 2014, 15:30–15:45, HSZ 304

Parity measurement in topological Josephson junctions — •François Crépin and Björn Trauzettel — Institute for Theoretical Physics and Astrophysics, University of Würzburg, 97074 Würzburg, Germany

We study the properties of a topological Josephson junction made of both edges of a 2D topological insulator. We show that, due to fermion parity pumping across the bulk, the global parity of the junction has a clear signature in the periodicity and critical value of the Josephson current. In particular, we find that the periodicity with the flux changes from 4π in a junction with an even number of quasi-particles to 2π in the odd sector. In the case of long junctions, we exhibit a rigorous mathematical connection between the spectrum of Andreev bound-states and the fermion parity anomaly, through bosonization. Additionally, we discuss the rather quantitative effects of Coulomb interactions on the Josephson current.