Effect of multiple charge traps on dephasing rates of a Josephson charge qubit system

TL;DR

This paper investigates how multiple charge traps influence the dephasing rates of a Josephson charge qubit, revealing that interactions between traps can suppress dephasing, which is crucial for quantum computing stability.

Contribution

It introduces a model considering interactions between multiple charge traps and analyzes their effect on qubit dephasing rates, highlighting the role of Coulomb blockade effects.

Findings

Interaction between charge traps suppresses dephasing.

Coulomb blockade affects transition probabilities.

Dephasing rates depend on trap occupation states.

Abstract

We examine the dephasing rate of a Josephson charge qubit system due to background charge fluctuations. We consider single qubit and two-charge traps. The transition probability was controlled to a state where two traps were occupied. The transition probability was affected by the Coulomb blockade effect that occurs between two charge traps. To obtain the dephasing rate, we computed the spectra of random frequency modulation signals. Our results show that the interaction between charge traps suppresses dephasing.