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Qubit Seminar: Dr. Roman Riwar


Fractional charges in conventional sequential electron tunneling - Part 1

Abstract: The notion of a fractional charge was up until now reserved for quasiparticle excitations emerging from strongly correlated, topological quantum systems, such as Laughlin states in the fractional quantum Hall effect or, more recently, parafermions. In this seminar, I consider topological braiding transitions in the full counting statistics of standard sequential electron tunneling, and show that they can lead to an effective fractionalization of charge - strikingly in the absence of exotic quantum correlations. In this first part, I will dedicate most of the time to arguing how exactly the transport can be interpreted as fractional. For this purpose, I will deal with generalizations of the Fano factor, and discuss the notion of detectors with a finite resolution. I will then elaborate on the possibility of using topological transitions in the transport statistics for new applications, such as the unexpected possibility to directly measure features beyond the resolution limit of a detector. If time permits, I will briefly summarize the final main result of my work: namely that there emerges a topological invariant, which is directly related to the fractional charges. In particular, this invariant can be used to unveil a deep connection between this fractional charge effect and the topology of the fractional Josephson effect

05 Dec 2018 13:30
05 Dec 2018 14:30
PGl, Bld. 04.8, Room 142/143


Dr. Mohammad Ansari
Phone: +49 2461 61-4676
Fax: +49 2461 61-2620
email: m.ansari@fz-juelich.de