TY  - JOUR
AU  - Riwar, Roman
AU  - Glazman, L. I.
AU  - Catelani, G.
TI  - Dissipation by normal-metal traps in transmon qubits
JO  - Physical review / B
VL  - 98
IS  - 2
SN  - 2469-9950
CY  - Woodbury, NY
PB  - Inst.
M1  - FZJ-2018-04108
SP  - 024502
PY  - 2018
AB  - Quasiparticles are an intrinsic source of relaxation and decoherence for superconducting qubits. Recent works have shown that normal-metal traps may be used to evacuate quasiparticles, and potentially improve the qubit lifetime. Here, we investigate how far the normal metals themselves may introduce qubit relaxation. We identify the Ohmic losses inside the normal metal and the tunneling current through the normal-metal–superconductor interface as the relevant relaxation mechanisms. We show that the Ohmic loss contribution depends strongly on the device and trap geometry, as a result of the inhomogeneous electric fields in the qubit. The correction of the quality factor due to the tunneling current on the other hand is highly sensitive to the nonequilibrium distribution function of the quasiparticles. Overall, we show that even when choosing less than optimal parameters, the presence of normal-metal traps does not affect the quality factor of state-of-the-art qubits.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000437668600006
DO  - DOI:10.1103/PhysRevB.98.024502
UR  - https://juser.fz-juelich.de/record/850022
ER  -