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The prospect of intrinsically protected quantum computing is driving the research on topological quantum systems. Materials with a topologically nontrivial band structure are however difficult to manufacture experimentally. We recently showed that topological materials can be engineered by quite simple means, when considering a different space: superconducting junctions have the phase difference and the number of transported charges across the junction as conjugate variables. In the main part of the talk, I will present the example of a four-terminal junction whose energy spectrum exhibits Weyl singularities in the space of three independent phases, which thus play the role of quasimomenta. The nonzero Chern number can be directly probed through a transport measurement, namely, through a quantised transconductance. In the final part of the talk, I will provide an outlook on future directions. For one, electric circuits may be used to study topological phase transitions specific to open systems out of equilibrium, and secondly, they may exhibit a so far unexplored connection between topology and quantum thermodynamics.

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Roman Riwar, Institute for Theoretical Nanoelectronics, FZ Jülich
TP seminar room 0.03
Contact: Achim Rosch