Publications by authors named "O Coupiac"

We have implemented a new experimental set-up for precise measurements of current fluctuations in three-terminal devices. The system operates at very low temperatures (30 mK) and is equipped with three superconducting quantum interference devices (SQUIDs) as low noise current amplifiers. A SQUID input coil is connected to each terminal of a sample allowing the acquisition of time-dependent current everywhere in the circuit.

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We present measurements of current noise and cross correlations in three-terminal superconductor-normal-metal-superconductor (S-N-S) nanostructures that are potential solid-state entanglers thanks to Andreev reflections at the N-S interfaces. The noise-correlation measurements spanned from the regime where electron-electron interactions are relevant to the regime of incoherent multiple Andreev reflection. In the latter regime, negative cross correlations are observed in samples with closely spaced junctions.

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We present current noise measurements in a long diffusive superconductor-normal-metal-superconductor junction in the low voltage regime, in which transport can be partially described in terms of coherent multiple Andreev reflections. We show that, when decreasing voltage, the current noise exhibits a strong divergence together with a broad peak. We ascribe this peak to the mixing between the ac-Josephson current and the noise of the junction itself.

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