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We present low-temperature measurements of the low-frequency $1/f$ noise arising from an ensemble of two-level fluctuators in the oxide barrier of Al/AlO$_{x}$/Al Josephson junctions. The fractional noise power spectrum of the…

Superconductivity · Physics 2013-06-06 C. D. Nugroho , V. Orlyanchik , D. J. Van Harlingen

We present a simple microscopic model to show how fluctuating two--level systems in the Josephson junction tunnel barrier of thickness $L$ can modify the potential energy of the barrier and produce critical current noise spectra. We find…

Superconductivity · Physics 2007-11-13 Magdalena Constantin , Clare C. Yu

We have studied low-frequency resistance fluctuations in shadow-evaporated Al/AlOx/Al tunnel junctions. Between 300 K and 5 K the spectral density follows a 1/f-law. Below 5 K, individual defects distort the 1/f-shape of the spectrum. The…

We investigate critical current noise in short ballistic graphene Josephson junctions in the open-circuit gate-voltage limit within the McWorther model. We find flicker noise in a wide frequency range and discuss the temperature dependence…

Mesoscale and Nanoscale Physics · Physics 2021-04-20 Francesco M. D. Pellegrino , Giuseppe Falci , Elisabetta Paladino

Operation of Josephson electronics usually requires determination of the Josephson critical current $I_c$, which is affected both by fluctuations and measurement noise. Lock-in measurements allow obviation of $1/f$ noise and, therefore,…

Superconductivity · Physics 2021-12-09 Razmik A. Hovhannisyan , Olena M. Kapran , Taras Golod , Vladimir M. Krasnov

We compute the decoherence caused by $1/f$ fluctuations at low frequency $f$ in the critical current $I_0$ of Josephson junctions incorporated into flux, phase, charge and hybrid flux-charge superconducting quantum bits (qubits). The…

We have probed the switching dynamics of the Josephson critical current of a superconducting weak link by measuring its voltage/current characteristics while applying an ac current bias in the range 1-200 MHz. The weak link between two Nb…

Mesoscale and Nanoscale Physics · Physics 2020-09-23 Kevin Spahr , Jonathan Graveline , Chrustian Lupien , Marco Aprili , Bertrand Reulet

Josephson superconducting qubits and parametric amplifiers are prominent examples of superconducting quantum circuits that have shown rapid progress in recent years. With the growing complexity of such devices, the requirements for…

Critical current fluctuations with a 1/ f spectral density (f is frequency) are potentially a limiting source of intrinsic decoherence in superconducting quantum bits (qubits) based on Josephson tunnel junctions. Prior measurements of this…

Superconductivity · Physics 2007-05-23 Michael Mueck , Matthias Korn , C. G. A. Mugford , J. B. Kycia , John Clarke

Short ballistic graphene Josephson junctions sustain superconducting current with a non-sinusoidal current-phase relation up to a critical current threshold. The current-phase relation, arising from proximitized superconductivity, is…

Mesoscale and Nanoscale Physics · Physics 2020-01-09 Francesco M. D. Pellegrino , Giuseppe Falci , Elisabetta Paladino

We present measurements of 1/f frequency noise in both linear and Josephson-junction-embedded superconducting aluminum resonators in the low power, low temperature regime - typical operating conditions for superconducting qubits. The…

Superconductivity · Physics 2015-06-03 K. W. Murch , S. J. Weber , E. M. Levenson-Falk , R. Vijay , I. Siddiqi

We theoretically investigate the critical current of a thermally-biased SIS Josephson junction formed by electrodes made by different BCS superconductors. The response of the device is analyzed as a function of the asymmetry parameter,…

Mesoscale and Nanoscale Physics · Physics 2019-02-04 Claudio Guarcello , Alessandro Braggio , Paolo Solinas , Francesco Giazotto

We carry out an extensive experimental and theoretical study of the Josephson effect in S-N-S junctions made of a diffusive normal metal (N) embedded between two superconducting electrodes (S). Our experiments are performed on Nb-Cu-Nb…

Mesoscale and Nanoscale Physics · Physics 2009-10-31 P. Dubos , H. Courtois , B. Pannetier , F. K. Wilhelm , A. D. Zaikin , G. Schon

To verify the hypothesis about the common origin of the low frequency 1/f noise and the quantum f noise recently measured in the Josephson charge qubits, we study temperature dependence of the 1/f noise and decay of coherent oscillations.…

Superconductivity · Physics 2009-11-11 O. Astafiev , Yu. A. Pashkin , Y. Nakamura , T. Yamamoto , J. S. Tsai

We investigate the dynamics of a resistively shunted Josephson junction. We compute the Josephson frequency and the generalized impedances for a variety of the parameters, particularly with relevance to predicting the measurable effects of…

Superconductivity · Physics 2010-07-14 Fernando T Brandt , Josif Frenkel , John C Taylor

The intrinsic nonlinearity of Josephson junctions converts Gaussian current noise in the input into non-Gaussian voltage noise in the output. For a resistively shunted Josephson junction with white input noise we determine numerically…

Superconductivity · Physics 2015-05-18 D. S. Golubev , M. Marthaler , Y. Utsumi , Gerd Schon

We measured the critical temperatures and critical switching and retrapping currents of wide and narrow thin-film quasi-one-dimensional superconducting aluminum structures of the same thickness in zero magnetic field. For the first time, we…

Superconductivity · Physics 2026-05-01 V. I. Kuznetsov , O. V. Trofimov

Fluctuations of the current through a tunnel junction are measured using a Josephson junction. The current noise adds to the bias current of the Josephson junction and affects its switching out of the supercurrent branch. The experiment is…

Mesoscale and Nanoscale Physics · Physics 2009-02-17 Q. Le Masne , H. Pothier , Norman O. Birge , C. Urbina , D. Esteve

We investigate the in-field critical current density Jc(B) of SNS Josephson Junctions (JJs) and polycrystalline superconductors with grain boundaries modelled as Josephson type planar defects, both analytically and through computational…

Superconductivity · Physics 2021-10-06 A. I. Blair , D. P. Hampshire

We have studied the variation of critical current in Superconductor/Ferromagnet/Superconductor (S/F/S) Josephson Junctions as a function of ferromagnet thickness using a weakly-ferromagnetic alloy Pd82Ni12. Measurements were performed for…

Superconductivity · Physics 2012-08-27 Trupti S. Khaire , W. P. Pratt, , Norman O. Birge
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