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We have fabricated and measured a high-Q Josephson junction resonator with a tunable resonance frequency. A dc magnetic flux allows the resonance frequency to be changed by over 10 %. Weak coupling to the environment allows a quality factor…

Superconductivity · Physics 2015-06-25 K. D. Osborn , J. A. Strong , A. J. Sirois , R. W. Simmonds

We have developed a scheme for a high resolution measurement of the switching current distribution of a current biased Josephson tunnel junction using a timing technique. The measurement setup is implemented such that the digital control…

Superconductivity · Physics 2009-11-07 A. Wallraff , A. Lukashenko , C. Coqui , T. Duty , A. V. Ustinov

Spectroscopy is a powerful tool to probe physical, chemical, and biological systems. Recent advances in microfabrication have introduced novel, intriguing mesoscopic quantum systems including superconductor-semiconductor hybrid devices and…

Mesoscale and Nanoscale Physics · Physics 2021-11-04 J. Griesmar , R. H. Rodriguez , V. Benzoni , J. -D. Pillet , J. -L. Smirr , F. Lafont , Ç. Ö. Girit

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

Superconducting circuits incorporating Josephson tunnel junctions are widely used for fundamental research as well as for applications in fields such as quantum information and magnetometry. The quantum coherent nature of Josephson…

Mesoscale and Nanoscale Physics · Physics 2021-11-04 L. Peyruchat , J. Griesmar , J. -D. Pillet , Ç. Ö. Girit

We investigate, by experiments and numerical simulations, thermal activation processes of Josephson tunnel junctions in the presence of microwave radiation. When the applied signal resonates with the Josephson plasma frequency oscillations,…

Statistical Mechanics · Physics 2007-08-28 N. Grønbech-Jensen , M. G. Castellano , F. Chiarello , M. Cirillo , C. Cosmelli , V. Merlo , R. Russo , G. Torrioli

Superconductivity derives its most salient features from the coherence of its macroscopic wave function. The associated physical phenomena have now moved from exotic subjects to fundamental building blocks for quantum circuits such as…

Mesoscale and Nanoscale Physics · Physics 2015-07-10 Benoit Gaury , Joseph Weston , Xavier Waintal

We show that two capacitively-coupled Josephson junctions, in the quantum limit, form a simple coupled qubit system with effective coupling controlled by the junction bias currents. We compute numerically the energy levels and wave…

By coupling a quantum detector, a superconductor-insulator-superconductor junction, to a Josephson junction \textit{via} a resonant circuit we probe the high frequency properties, namely the ac complex admittance and the current…

Mesoscale and Nanoscale Physics · Physics 2012-03-02 Julien Basset , Hélène Bouchiat , Richard Deblock

Quantum bits, or qubits, are an example of coherent circuits envisioned for next-generation computers and detectors. A robust superconducting qubit with a coherent lifetime of $O$(100 $\mu$s) is the transmon: a Josephson junction…

Quantum Physics · Physics 2020-05-11 J. M. Kreikebaum , K. P. O'Brien , A. Morvan , I. Siddiqi

Josephson current of spin-entangled electrons through the two branches of a SQUID-like structure with two quantum dots exhibits a magnetic-flux response different from the conventional Josephson current. Due to their interference, the…

Superconductivity · Physics 2011-11-15 Zhi Wang , Xiao Hu

We show the existence of a resonant behavior of the current of Brownian particles confined in a pulsating channel. The interplay between the periodic oscillations of the shape of the channel and a force applied along its axis leads to an…

Soft Condensed Matter · Physics 2016-12-15 M. Florencia Carusela , J. Miguel Rubí

We investigate the switching current distributions of ferromagnetic anomalous Josephson junctions subjected to a linearly increasing bias current. Our study uncovers a significant correlation between the position of the switching current…

Superconductivity · Physics 2023-10-12 Claudio Guarcello , F. Sebastián Bergeret , Roberta Citro

Synchronization of Bloch oscillations in small Josephson junctions (JJs) under microwave radiation, which leads to current quantization, has been proposed as an effect that is dual to the appearance of Shapiro steps. This current…

We describe a microwave photon counter based on the current-biased Josephson junction. The junction is tuned to absorb single microwave photons from the incident field, after which it tunnels into a classically observable voltage state.…

Superconductivity · Physics 2015-05-20 Y. -F. Chen , D. Hover , S. Sendelbach , L. Maurer , S. T. Merkel , E. J. Pritchett , F. K. Wilhelm , R. McDermott

We report the realization of a ballistic Josephson interferometer. The interferometer is made by a quantum ring etched in a nanofabricated two-dimensional electron gas confined in an InAs-based heterostructure laterally contacted to…

Mesoscale and Nanoscale Physics · Physics 2013-05-17 A. Fornieri , M. Amado , F. Carillo , F. Dolcini , G. Biasiol , L. Sorba , V. Pellegrini , F. Giazotto

Bias lines routed over a ground plane naturally form microstrip lines associated with the presence of a capacitance. This can lead to unwanted resonances when coupled to Josephson junctions. This work presents an electrical model of a…

Applied Physics · Physics 2023-07-19 Ugur Yilmaz , Sasan Razmkhah , Romain Collot , Juergen Kunert , Ronny Stolz , Pascal Febvre

We present measurements on microwave spectroscopy on a double quantum dot with an on-chip microwave source. The quantum dots are realized in the two-dimensional electron gas of an AlGaAs/GaAs heterostructure and are weakly coupled in series…

Mesoscale and Nanoscale Physics · Physics 2009-10-31 A. W. Holleitner , H. Qin , F. Simmel , B. Irmer , R. H. Blick , J. P. Kotthaus , A. V. Ustinov , K. Eberl

We investigate the dynamics of the phase variable of an ideal underdamped Josephson junction in switching current experiments. These experiments have provided the first evidence for macroscopic quantum tunneling in large Josephson junctions…

Superconductivity · Physics 2009-11-11 G. S. Paraoanu

We study adiabatic charge transfer in a superconducting Cooper pair pump, focusing on the influence of current measurement on coherence. We investigate the limit where the Josephson coupling energy $E_J$ between the various parts of the…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 Rosario Fazio , F. W. J. Hekking , J. P. Pekola