Waiting time distributions in a two-level fluctuator coupled to a superconducting charge detector

Jenei, Máté; Potaņina, Elīna; Zhao, Ruichen; Tan, Kuan Yen; Rossi, Alessandro; Tanttu, Tuomo; Chan, KW; Sevriuk, Vasilii; Möttönen, Mikko; Dzurak, A. S.

doi:10.1103/physrevresearch.1.033163

Cited by 15 publications

(9 citation statements)

References 64 publications

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“…(ii) The estimated best-fit Δ P ± parameters correlate well with the standard deviation of the P ± in the underlying simulation. (iii) Even a single fluctuator with a fixed switching rate (bimodal distribution of P ± and a Poisson distribution of switching times 40 ) can generate detectable excess noise still consistent with our Dirichlet-based statistical models. As for the physics of the real device in a noisy environment, the simulations favor an explanation of the detected excess noise by the presence of multiple charge fluctuators over a single two-level system due to the absence of a bimodal signature in Fig.…”

Section: Resultssupporting

confidence: 76%

A random-walk benchmark for single-electron circuits

et al. 2021

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Mesoscopic integrated circuits aim for precise control over elementary quantum systems. However, as fidelities improve, the increasingly rare errors and component crosstalk pose a challenge for validating error models and quantifying accuracy of circuit performance. Here we propose and implement a circuit-level benchmark that models fidelity as a random walk of an error syndrome, detected by an accumulating probe. Additionally, contributions of correlated noise, induced environmentally or by memory, are revealed as limits of achievable fidelity by statistical consistency analysis of the full distribution of error counts. Applying this methodology to a high-fidelity implementation of on-demand transfer of electrons in quantum dots we are able to utilize the high precision of charge counting to robustly estimate the error rate of the full circuit and its variability due to noise in the environment. As the clock frequency of the circuit is increased, the random walk reveals a memory effect. This benchmark contributes towards a rigorous metrology of quantum circuits.

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Section: Resultssupporting

confidence: 76%

A random-walk benchmark for single-electron circuits

et al. 2021

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“…In a recent article some of us considered the distribution of waiting times between emitted electrons, and we showed that it contains a wealth of information about the Cooper pair splitter, for instance the characteristic timescales that govern the underlying tunneling processes [51]. Measurements of electron waiting times, however, require real-time detection of the individual tunneling events [52][53][54]. By contrast, conventional quantum transport experiments typically measure the electric currents and their fluctuations [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24], which are thus our main focus here.…”

Section: Introductionmentioning

confidence: 99%

Noise and full counting statistics of a Cooper pair splitter

et al. 2020

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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.

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“…47 Measurements of electron waiting times, however, require real-time detection of the individual tunneling events. [48][49][50] By contrast, conventional quantum transport experiments typically measure the electric currents and their fluctuations, [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23] which are thus our main focus here. In particular, we consider the noise power spectra of the currents in the output leads [51][52][53][54][55] and their power-power correlations, which we use to analyze the physical processes involved in the splitting of Cooper pairs.…”

Section: Introductionmentioning

confidence: 99%

Noise and full counting statistics of a Cooper pair splitter

Walldorf,

Brange,

Padurariu

et al. 2020

Preprint

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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.

show abstract

Waiting time distributions in a two-level fluctuator coupled to a superconducting charge detector

Cited by 15 publications

References 64 publications

A random-walk benchmark for single-electron circuits

A random-walk benchmark for single-electron circuits

Noise and full counting statistics of a Cooper pair splitter

Noise and full counting statistics of a Cooper pair splitter

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