A random-walk benchmark for single-electron circuits

Abstract

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.

Ultimate Accuracy of Frequency to Power Conversion by Single-Electron Injection

“…Here, we have analyzed a BCS superconductor as the energy filter; similar analysis could be done for other types of emitters such as single-level quantum dots. Finally, we believe that the present error analysis can possibly be complemented by pumping error accounting [24].…”

Precision measurement of an electron pump at 2 GHz; the frontier of small DC current metrology

“…Another plausible scenario exploits the ability to perform single-charge detection to verify the accuracy of electron transfer independently of a measurement of the DC current. One circuit topology works as a 'self-referenced' current standard [18,19], albeit at currents well below 1 pA. Another topology [17] allows the pump to work separately in a 'counting mode' and a 'pumping mode'.…”

“…The accuracy of loading electrons into a semiconductor pump has also been verified at the level of a few ppm [17]. If several pumps are operated in series slowly enough (I P ≪ 1 pA), it is even possible to rigorously account for electron transfer errors by real-time detection of the pumped electrons [18,19].…”

Revealing the stochastic kinetics evolution of photocatalytic CO2reduction

“…When the physical model is built, the charge carrier behavior can be simulated by employing a charge random behavior approach considering the aforementioned random processes in charge carrier kinetics and interfacial reaction. 54,55 Electrons and holes move freely in photocatalysts, and a multiple-trapping method is utilized for calculating the migration of photogenerated charge carriers, programming details of this method can be found in previous works. 32,42,56 While charge carriers are moving within photocatalysts, they may be captured by defects or surface active sites.…”