Balanced comparator for RSFQ qubit readout

T. Ohki, A. Savin, Juha Hassel, Leif Grönberg, T. Karminskaya, A. Kidiyarova-Shevchenko

Research output: Contribution to journalArticleScientificpeer-review

6 Citations (Scopus)

Abstract

The balanced comparator is an essential part of RSFQ-based readout for superconducting qubits. In this paper we report measurements of the sensitivity of the balanced comparator fabricated in a specialized 30 A/cm2 process with 3.6 ìm critical currents and measured at 30-500 mK. At sampling frequency of 3.5 GHz the measured gray zone is ÄI = 104 nA. Due to electron overheating in the shunt resistors the effective noise temperature is 140 mK. The gray zone has a strong dependence on sampling frequency above 5 GHz due to over-clocking. Related measurements have been reported where cooling fins and reduced critical current density of 10 A/cm2 were used, and a quantum limited gray zone of 40 nA was achieved. This makes single shot readout possible for the phase, RF-SQUID and persistent current qubits. The readout speed is 30-50 ps, which is quite favorable for error correction schemes.
Original languageEnglish
Pages (from-to)128-131
JournalIEEE Transactions on Applied Superconductivity
Volume17
Issue number2
DOIs
Publication statusPublished - 2007
MoE publication typeA1 Journal article-refereed

Fingerprint

readout
Sampling
Fins (heat exchange)
Critical currents
SQUIDs
critical current
cooling fins
Error correction
sampling
Resistors
noise temperature
shunts
Cooling
resistors
shot
Electrons
current density
sensitivity
Temperature
electrons

Keywords

  • Balanced comparator
  • Qubit readout
  • RSFQ

Cite this

Ohki, T., Savin, A., Hassel, J., Grönberg, L., Karminskaya, T., & Kidiyarova-Shevchenko, A. (2007). Balanced comparator for RSFQ qubit readout. IEEE Transactions on Applied Superconductivity, 17(2), 128-131. https://doi.org/10.1109/TASC.2007.897319
Ohki, T. ; Savin, A. ; Hassel, Juha ; Grönberg, Leif ; Karminskaya, T. ; Kidiyarova-Shevchenko, A. / Balanced comparator for RSFQ qubit readout. In: IEEE Transactions on Applied Superconductivity. 2007 ; Vol. 17, No. 2. pp. 128-131.
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Ohki, T, Savin, A, Hassel, J, Grönberg, L, Karminskaya, T & Kidiyarova-Shevchenko, A 2007, 'Balanced comparator for RSFQ qubit readout', IEEE Transactions on Applied Superconductivity, vol. 17, no. 2, pp. 128-131. https://doi.org/10.1109/TASC.2007.897319

Balanced comparator for RSFQ qubit readout. / Ohki, T.; Savin, A.; Hassel, Juha; Grönberg, Leif; Karminskaya, T.; Kidiyarova-Shevchenko, A.

In: IEEE Transactions on Applied Superconductivity, Vol. 17, No. 2, 2007, p. 128-131.

Research output: Contribution to journalArticleScientificpeer-review

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AU - Ohki, T.

AU - Savin, A.

AU - Hassel, Juha

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AU - Karminskaya, T.

AU - Kidiyarova-Shevchenko, A.

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