Working Point Adjustable DC-SQUID for the Readout of Gap Tunable Flux Qubit

Author

Hui Deng ; Yulin Wu ; Yarui Zheng ; Akhtar, Naheed ; Jie Fan ; Xiaobo Zhu ; Jie Li ; Yirong Jin ; Dongning Zheng

Author_Institution

Beijing Nat. Lab. for Condensed Matter Phys., Inst. of Phys., Beijing, China

Volume

25

Issue

3

fYear

2015

fDate

Jun-15

Firstpage

1

Lastpage

4

Abstract

In flux qubits, qubit states are commonly read out by a dc superconducting quantum interference device (SQUID), which is inductively coupled to the qubit and works as a persistent current detector. However, neither the bottom nor the top regions of the critical current modulation curve of the SQUID can be used for the readout. In this paper, we show that a flux-trap loop inserted to the readout SQUID provides the ability to adjust the working point, which helps to avoid this constraint. This improvement is useful for some complicated flux qubit experiments.

Keywords

SQUIDs; current detector; current modulation curve; dc superconducting quantum interference device; flux-trap loop; gap tunable flux qubit; working point adjustable DC-SQUID; Critical current density (superconductivity); Current measurement; Josephson junctions; Junctions; Modulation; SQUIDs; Switches; Flux qubit; flux qubit; flux-trap loop; gap tunable; working point adjustable;

fLanguage

English

Journal_Title

Applied Superconductivity, IEEE Transactions on

Publisher

ieee

ISSN

1051-8223

Type

jour

DOI

10.1109/TASC.2015.2399272

Filename

7029620