Noise correlations in three-terminal diffusive superconductor-normal-metal-superconductor nanostructures

Area of Science:

• Condensed Matter Physics
• Quantum Information Science
• Nanotechnology

Background:

• Superconductor-normal-metal-superconductor (S-N-S) nanostructures are promising for solid-state quantum information processing.
• Andreev reflections at normal-superconducting interfaces are key to generating entangled states.

Purpose of the Study:

• To investigate current noise and cross correlations in S-N-S nanostructures.
• To explore the behavior of these correlations across different interaction regimes.
• To assess the potential of these devices as solid-state entanglers.

Main Methods:

• Fabrication and characterization of three-terminal S-N-S nanostructures.
• Measurements of current noise and cross-correlations.
• Systematic variation of junction spacing and measurement across different electron interaction regimes.

Main Results:

• Noise and cross-correlation measurements were performed in S-N-S nanostructures.
• The study covered regimes from relevant electron-electron interactions to incoherent multiple Andreev reflection.
• Negative cross correlations were observed in samples with closely spaced junctions.

Conclusions:

• The observed negative cross correlations in closely spaced junctions suggest potential for S-N-S nanostructures as solid-state entanglers.
• Understanding noise and correlations is crucial for developing quantum information devices based on Andreev reflections.