Noise and full counting statistics of a Cooper pair splitter

Nicklas Walldorf*, Fredrik Brange, Ciprian Padurariu, Christian Flindt

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

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Abstract

We investigate theoretically the noise and the full counting statistics of electrons that are emitted from a superconductor into two spatially separated quantum dots by the splitting of Cooper pairs and further on collected in two normal-state electrodes. With negatively biased drain electrodes and a large superconducting gap, the dynamics of the Cooper pair splitter can be described by a Markovian quantum master equation. Using techniques from full counting statistics, we evaluate the electrical currents, their noise power spectra, and the power-power correlations in the output leads. The current fluctuations can be attributed to the competition between Cooper pair splitting and elastic cotunneling between the quantum dots via the superconductor. In one regime, these processes can be clearly distinguished in the cross-correlation spectrum with peaks and dips appearing at characteristic frequencies associated with elastic cotunneling and Cooper pair splitting, respectively. We corroborate this interpretation by analyzing the charge transport fluctuations in the time domain, specifically by investigating the g((2)) function of the output currents. Our work identifies several experimental signatures of the fundamental transport processes involved in Cooper pair splitting and provides specific means to quantify their relative strengths. As such, our results may help guide and interpret future experiments on current fluctuations in Cooper pair splitters.

Original languageEnglish
Article number205422
Number of pages14
JournalPhysical Review B
Volume101
Issue number20
DOIs
Publication statusPublished - 20 May 2020
MoE publication typeA1 Journal article-refereed

Keywords

  • RATE-EQUATIONS
  • QUANTUM
  • TRANSPORT

Projects

Finnish Centre of Excellence in Quantum Technology

Flindt, C., Potanina, E., Burset Atienza, P. & Pyhäranta, T.

01/01/201831/12/2020

Project: Academy of Finland: Other research funding

Quantum Engineering of Charge, Heat, and Entropy Production in Nano-Devices

Flindt, C., Deger, A., Potanina, E., Menczel, P., Norrman Brange, F. & Pyhäranta, T.

01/09/201731/08/2021

Project: Academy of Finland: Other research funding

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