Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

IEEE Transactions on Instrumentation and Measurement

The quantum roulette noise thermometer

Ling Yun Hao, John C. Gallop, J.C. Macfarlane, D.A. Peden, R.P. Reed

Published Apr 1, 1999• 7 citations
Publisher

Abstract

A novel form of primary thermometer called the quantum roulette noise thermometer (QRNT), based on flux quantization in a high temperature superconducting (HTS) ring, interrupted by a Josephson junction, has been proposed. The basis of the QRNT is that the flux state of the ring is allowed to evolve freely, and is repeatedly interrogated to establish a probability distribution from which the temperature of the device is derived. Unlike other superconductivity-based noise thermometers, this device is essentially dissipationless, requires no input or output connections, and may be remotely interrogated. The QRNT has the potential to provide high accuracy with short measuring times. Prototype QRNT devices based on thin HTS films have been fabricated and results of initial experimental measurements are presented. Parameters of the experimental devices are compared with predictions of the theoretical model.

DOI
10.1109/19.769681

Related papers

The quantum roulette noise thermometer

L. Hao, J.C. Gallop, R.P. Reed +2 more

A novel form of primary thermometer called the quantum roulette noise thermometer (QRNT), based on flux quantisation in a HTS superconducting ring, has been proposed. The basis of the QRNT is that the flux state of a SQUID ring is allowed to evolve freely. The flux state is repeatedly interrogated to establish a probability distribution from which the temperature of the device is derived.

Conference on Precision Electromagnetic Measurements•Nov 27, 2002•1 citation

HTS SQUID application as a quantum roulette noise thermometer

L. Hao, John C. Gallop, R.P. Reed +2 more

We describe a cryogenic primary thermometer called the Quantum Roulette Noise Thermometer (QRNT), which is based on flux quantisation in a HTS superconducting ring. The basis of the QRNT is that the flux state of a double junction SQUID ring (in thermal contact with a heat bath whose temperature is to be measured) is allowed to evolve freely. The flux state is repeatedly interrogated to establish a probability distribution from which the absolute temperature may be derived. The QRNT is in principle dissipationless and has the potential to provide high accuracy with short measuring time. The QRNT prototype device which employs a YBCO thin film on an MgO bi-crystal substrate has been designed and fabricated. The superconducting ring of overall dimensions 6 mm/spl times/8 mm is broken by two grain boundary Josephson junctions of size 5 /spl mu/m/spl times/3 /spl mu/m. The state of the junctions is switched between superconducting and resistive by means of small currents applied to a superconducting strip line located near the junctions. A dc SQUID, which is used to read out the flux state of the QRNT ring, is operated at 77 K while the QRNT device can be set at any desired temperature above 10 K. Ongoing experimental measurements are described with reference to the expected theoretical predictions.

IEEE Transactions on Applied Superconductivity•Jun 1, 1999•3 citations

Quantum Roulette Noise Thermometer: Progress and prospects

R.A.M. Lee, L. Hao, D.A. Peden +3 more

A novel form of primary thermometer called the Quantum Roulette Noise Thermometer (QRNT) has been fabricated and is presently undergoing feasibility studies. This device utilises flux quantisation in a high temperature superconducting ring interrupted by two closely spaced, parallel, Josephson junctions. Several devices have been fabricated and different methods investigated for measuring the statistical distribution of trapped flux states. We report the results of these endeavours with emphasis on a method for suppressing I/sub c/ by applying an r.f. field to the junctions.

IEEE Transactions on Applied Superconductivity•Mar 1, 2001•9 citations

The future of quantum roulette noise thermometry.

C H Webster

The Quantum Roulette Noise Thermometer (QRNT) is a unique type of primary thermometer. Rather than probing a classical thermodynamic variable whose value depends on the average motion of an ensemble of microscopic particles, it makes a series of consecutive measurements of a quantum variable, the flux trapped within a superconducting ring. From the statistical distribution of flux measurements the temperature can be obtained. In principle, the device could operate over a wide range of temperatures, with the upper limit dependent on the superconducting ma- terial chosen for the ring. Its accuracy would be limited by statistical sample size. The QRNT directly addresses the primary objectives of the UK National Measurement System (NMS) Quantum Programme: an NMS based wholly on quantum processes, fundamental constants and the use of portable quantum standards with full primary accuracy. This report reviews preliminary research and assesses the future benefit of QRNT devices to thermal metrology.

•Jan 1, 2006•1 citation

Influence of the Josephson junction on the impedance and noise of a resistive superconductive quantum interference device

Robert J. Soulen, William E. Fogle, Jack H. Colwell +2 more

The impedance and noise of a resistive superconductive quantum interference device (R-SQUID) have been measured as a function of the dc and rf currents applied to it. The Josephson junction was adjustable so that data were also taken for several values of the junction critical current. The results were compared with the predictions of a resistively shunted junction (RSJ) model which takes into account the influence of the Josephson junction on the impedance and noise. The agreement was found to be quite good and demonstrates that the noise in the circuit is well understood. Use of the R-SQUID as a noise thermometer below 1 K is assessed in terms of corrections due to the RSJ model. It is demonstrated how the dc and rf currents may be adjusted so that the total noise of the R-SQUID is reduced to within 0.1% of the Johnson noise generated by the resistor alone. Under these conditions, the R-SQUID may be used as a noise thermometer to determine thermodynamic temperature to this inaccuracy from 6 to 700 mK.

Journal of Applied Physics•Oct 15, 1993•4 citations

Measurement of the dynamic error rate of a high temperature superconductor rapid single flux quantum comparator

Ben J. Ruck, B. Oelze, Regina Dittmann +4 more

The application of high temperature superconductor (HTS) Josephson junctions in digital rapid single flux quantum circuits requires a careful study of the influence of thermal noise on the bit error rate (BER). We have determined experimentally, for the first time, the BER of a HTS rapid single flux quantum circuit. A comparator, formed by two Josephson junctions, was integrated in a Josephson transmission line ring oscillator, allowing us to perform high speed testing of the comparator at GHz frequencies. For fabrication, focused-electron-beam-irradiated junctions have been used because of their small parameter spread and excellent alignment possibilities. A BER of less than 10−11 was obtained at 39 K.

Applied Physics Letters•May 4, 1998•15 citations
A novel form of primary thermometer called the quantum roulette noise thermometer (QRNT), based on flux quantization in a high temperature superconducting (HTS) ring, interrupted by a Josephson junction, has been proposed. The basis of the QRNT is that the flux state of the ring is allowed to evolve freely, and is repeatedly interrogated to establish a probability distribution from which the temperature of the device is derived. Unlike other superconductivity-based noise thermometers, this device is essentially dissipationless, requires no input or output connections, and may be remotely interrogated. The QRNT has the potential to provide high accuracy with short measuring times. Prototype QRNT devices based on thin HTS films have been fabricated and results of initial experimental measurements are presented. Parameters of the experimental devices are compared with predictions of the theoretical model.
We describe a cryogenic primary thermometer called the Quantum Roulette Noise Thermometer (QRNT), which is based on flux quantisation in a HTS superconducting ring. The basis of the QRNT is that the flux state of a double junction SQUID ring (in thermal contact with a heat bath whose temperature is to be measured) is allowed to evolve freely. The flux state is repeatedly interrogated to establish a probability distribution from which the absolute temperature may be derived. The QRNT is in principle dissipationless and has the potential to provide high accuracy with short measuring time. The QRNT prototype device which employs a YBCO thin film on an MgO bi-crystal substrate has been designed and fabricated. The superconducting ring of overall dimensions 6 mm/spl times/8 mm is broken by two grain boundary Josephson junctions of size 5 /spl mu/m/spl times/3 /spl mu/m. The state of the junctions is switched between superconducting and resistive by means of small currents applied to a superconducting strip line located near the junctions. A dc SQUID, which is used to read out the flux state of the QRNT ring, is operated at 77 K while the QRNT device can be set at any desired temperature above 10 K. Ongoing experimental measurements are described with reference to the expected theoretical predictions.
A novel form of primary thermometer called the Quantum Roulette Noise Thermometer (QRNT) has been fabricated and is presently undergoing feasibility studies. This device utilises flux quantisation in a high temperature superconducting ring interrupted by two closely spaced, parallel, Josephson junctions. Several devices have been fabricated and different methods investigated for measuring the statistical distribution of trapped flux states. We report the results of these endeavours with emphasis on a method for suppressing I/sub c/ by applying an r.f. field to the junctions.
The Quantum Roulette Noise Thermometer (QRNT) is a unique type of primary thermometer. Rather than probing a classical thermodynamic variable whose value depends on the average motion of an ensemble of microscopic particles, it makes a series of consecutive measurements of a quantum variable, the flux trapped within a superconducting ring. From the statistical distribution of flux measurements the temperature can be obtained. In principle, the device could operate over a wide range of temperatures, with the upper limit dependent on the superconducting ma- terial chosen for the ring. Its accuracy would be limited by statistical sample size. The QRNT directly addresses the primary objectives of the UK National Measurement System (NMS) Quantum Programme: an NMS based wholly on quantum processes, fundamental constants and the use of portable quantum standards with full primary accuracy. This report reviews preliminary research and assesses the future benefit of QRNT devices to thermal metrology.
The impedance and noise of a resistive superconductive quantum interference device (R-SQUID) have been measured as a function of the dc and rf currents applied to it. The Josephson junction was adjustable so that data were also taken for several values of the junction critical current. The results were compared with the predictions of a resistively shunted junction (RSJ) model which takes into account the influence of the Josephson junction on the impedance and noise. The agreement was found to be quite good and demonstrates that the noise in the circuit is well understood. Use of the R-SQUID as a noise thermometer below 1 K is assessed in terms of corrections due to the RSJ model. It is demonstrated how the dc and rf currents may be adjusted so that the total noise of the R-SQUID is reduced to within 0.1% of the Johnson noise generated by the resistor alone. Under these conditions, the R-SQUID may be used as a noise thermometer to determine thermodynamic temperature to this inaccuracy from 6 to 700 mK.
The application of high temperature superconductor (HTS) Josephson junctions in digital rapid single flux quantum circuits requires a careful study of the influence of thermal noise on the bit error rate (BER). We have determined experimentally, for the first time, the BER of a HTS rapid single flux quantum circuit. A comparator, formed by two Josephson junctions, was integrated in a Josephson transmission line ring oscillator, allowing us to perform high speed testing of the comparator at GHz frequencies. For fabrication, focused-electron-beam-irradiated junctions have been used because of their small parameter spread and excellent alignment possibilities. A BER of less than 10−11 was obtained at 39 K.