Journal Article

FZJ-2018-04108

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Dissipation by normal-metal traps in transmon qubits

Riwar, R.FZJ* ; Glazman, L. I. ; Catelani, G. (Corresponding author)FZJ*

2018
Inst. Woodbury, NY

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Please use a persistent id in citations: http://hdl.handle.net/2128/19289  doi:10.1103/PhysRevB.98.024502

Abstract: 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.

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Contributing Institute(s):

1. JARA Institut Quanteninformation (PGI-11)
2. Theoretische Nanoelektronik (PGI-2)

Research Program(s):

1. 144 - Controlling Collective States (POF3-144) (POF3-144)

Appears in the scientific report 2018

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Database coverage:
; ; ; Current Contents - Physical, Chemical and Earth Sciences ; Ebsco Academic Search ; IF < 5 ; JCR ; SCOPUS ; Science Citation Index ; Science Citation Index Expanded ; Thomson Reuters Master Journal List ; Web of Science Core Collection

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