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The statistics of electron transport in a quantum conductor is affected by fluctuations of its voltage bias. Here we show experimentally how a third order correlation in the electromagnetic field arises from the noise of a tunnel junction…

Mesoscale and Nanoscale Physics · Physics 2025-04-30 Clovis Farley , Edouard Pinsolle , Bertrand Reulet

Quantum mechanics can strongly influence the noise properties of mesoscopic devices. To probe this effect we have measured the current fluctuations at high-frequency (5-90 GHz) using a superconductor-insulator-superconductor tunnel junction…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 R. Deblock , E. Onac , L. Gurevich , L. P. Kouwenhoven

We propose a microscopic model of critical current noise in Josephson-junctions based on individual trapping-centers in the tunnel barrier hybridized with electrons in the superconducting leads. We calculate the noise exactly in the limit…

Superconductivity · Physics 2009-09-19 Rogerio de Sousa , K. Birgitta Whaley , Theresa Hecht , Jan von Delft , Frank K. Wilhelm

We observe a subharmonic gap sturucture (SGS) and the Josephson effect in superconducting scanning tunneling microscope junctions with resistances below 100 kOhm. The magnitude of the n=2 SGS is shown to scale with the square of the…

Superconductivity · Physics 2007-05-23 O. Naaman , R. C. Dynes

Josephson effect in short ballistic SINIS and SIFIS double-tunnel junctions, consisting of clean superconductors (S), a normal metal (N) or metallic ferromagnet (F), and insulating interfaces (I) is studied. For SINIS double-tunnel…

Mesoscale and Nanoscale Physics · Physics 2009-11-11 Z. Radović , I. Petković , N. M. Chtchelkatchev

We investigate the current-voltage characteristics of high-transparency superconductor-insulator-normal metal (SIN) junctions with the specific tunnel resistance below 30 kOhm per square micron. The junctions were fabricated from different…

Mesoscale and Nanoscale Physics · Physics 2009-11-11 S. V. Lotkhov , D. V. Balashov , M. I. Khabipov , F. -I. Buchholz , A. B. Zorin

Josephson junctions made from aluminium and its oxide are the most commonly used functional elements for superconducting circuits and qubits. It is generally known that the disordered thin-film AlOx contains atomic tunneling systems.…

Superconductivity · Physics 2018-05-30 Saskia M. Meißner , Arnold Seiler , Jürgen Lisenfeld , Alexey V. Ustinov , Georg Weiss

Superconducting qubits are solid state electrical circuits fabricated using techniques borrowed from conventional integrated circuits. They are based on the Josephson tunnel junction, the only non-dissipative, strongly non-linear circuit…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 M. H. Devoret , A. Wallraff , J. M. Martinis

In this work, a Josephson junction consisting of two superconducting layers sandwiching an insulating layer is explored, which is subject to the effects of thermal fluctuations. The precise expressions for the evolution of Josephson phase…

Superconductivity · Physics 2024-03-05 Shenglan Yuan

Andreev reflection between a normal metal and a superconductor whose order parameter exhibits quantum phase fluctuations is examined. The approach chosen is non perturbative in the tunneling Hamiltonian and enables to probe the whole range…

Superconductivity · Physics 2009-11-07 P. Devillard , R. Guyon , T. Martin , I. Safi , B. K. Chakraverty

We investigate the noise current in a thermally biased tunnel junction between two superconductors with different zero-temperature gaps. When the Josephson effect is suppressed, this structure can support a nonlinear thermoelectric effect…

Mesoscale and Nanoscale Physics · Physics 2020-11-26 G. Marchegiani , A. Braggio , F. Giazotto

We have found experimentally that the noise of ballistic electron transport in a superconductor/semiconductor/superconductor junction is enhanced relative to the value given by the general relation, S_V=2eIR^2coth(eV/2kT), for two voltage…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 F. E. Camino , V. V. Kuznetsov , E. E. Mendez , Th. Schaepers , V. A. Guzenko , H. Hardtdegen

We consider the linear and non-linear electromagnetic responses of a nanowire connecting two bulk superconductors. Andreev states appearing at a finite phase bias substantially affect the finite-frequency admittance of such a wire junction.…

Superconductivity · Physics 2013-10-25 F. Kos , S. E. Nigg , L. I. Glazman

We examine current fluctuations in tunnel junctions driven by a superposition of a constant and a sinusoidal voltage source. In standard setups the external voltage is applied to the tunneling element via an impedance providing an…

Mesoscale and Nanoscale Physics · Physics 2016-08-03 Moritz Frey , Hermann Grabert

We study quantum-mechanically the frequency-dependent current noise of a tunnel-junction coupled to a nanomechanical oscillator. The cases of both DC and AC voltage bias are considered, as are the effects of intrinsic oscillator damping.…

Mesoscale and Nanoscale Physics · Physics 2009-09-29 A. A. Clerk , S. M. Girvin

We calculate the current-pressure relation for pinholes connecting two volumes of bulk superfluid 3He-B. The theory of multiple Andreev reflections, adapted from superconducting weak links, leads to a nonlinear dependence of the dc current…

Superconductivity · Physics 2009-05-24 J. K. Viljas , E. V. Thuneberg

Quantum fluctuations in a current biased Josephson junction, described in terms of the RCSJ-model, are considered. The fluctuations of the voltage and phase across the junction are assumed to be initiated by equilibrium current fluctuations…

Superconductivity · Physics 2009-11-07 Y. Levinson

The current-voltage characteristics of Josephson junctions exhibit a subharmonic gap structure (SGS), denoting jumps at specific voltages. While the prevalent multiple Andreev reflection theory matches the experimentally observed SGS, it is…

Mesoscale and Nanoscale Physics · Physics 2025-05-09 Aritra Lahiri , Sang-Jun Choi , Björn Trauzettel

We investigate the possibility to employ magnetic Josephson junctions as magnetic-noise detectors. To illustrate our idea, we consider a system consisting of a quantum dot coupled to superconducting leads in the presence of an external…

Superconductivity · Physics 2023-10-09 Roberto Capecelatro , Valentina Brosco , Gabriele Campagnano , Procolo Lucignano

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