TY  - JOUR
AU  - Herrig, Tobias
AU  - Riwar, Roman
TI  - Cooper-pair transistor as a minimal topological quantum circuit
JO  - Physical review research
VL  - 4
IS  - 1
SN  - 2643-1564
CY  - College Park, MD
PB  - APS
M1  - FZJ-2021-05384
SP  - 013038
PY  - 2022
AB  - The outlook of protected quantum computing spurred enormous progress in the search for topological materials, sustaining a continued race to find the most experimentally feasible platform. Here we show that one of the simplest quantum circuits, the Cooper-pair transistor, exhibits a nontrivial Chern number which has not yet been discussed, in spite of the exhaustive existing literature. Surprisingly, the resulting quantized current response is robust with respect to a large number of external perturbations, most notably low-frequency charge noise and quasiparticle poisoning. Moreover, the fact that the higher bands experience crossings with higher topological charges leads to all the bands having the same Chern number, such that there is no restriction to stay close to the ground state. Remaining small perturbations are investigated based on a generic master equation approach. Finally, we discuss a feasible protocol to measure the quantized current.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000759216100004
DO  - DOI:10.1103/PhysRevResearch.4.013038
UR  - https://juser.fz-juelich.de/record/903744
ER  -