Dephasing of coupled spin qubit system during gate operations due to background charge fluctuations

TL;DR

This paper investigates how background charge fluctuations cause dephasing in coupled spin qubit systems during gate operations, affecting entanglement, fidelity, and purity, which is crucial for quantum computing reliability.

Contribution

It specifically analyzes the impact of background charge fluctuations on coupled spin qubits, highlighting their role in dephasing during two-qubit gate operations.

Findings

Background charge fluctuations induce dephasing in coupled spin qubits.

Fluctuations affect entanglement, fidelity, and purity during gates.

Background charge noise is a significant dephasing channel.

Abstract

It has been proposed that a quantum computer can be constructed based on electron spins in quantum dots or based on a superconducting nanocircuit. During two-qubit operations, the fluctuation of the coupling parameters is a critical factor. One source of such fluctuation is the stirring of the background charges. We focused on the influence of this fluctuation on a coupled spin qubit system. The induced fluctuation in exchange coupling changes the amount of entanglement, fidelity, and purity. In our previous study, the background charge fluctuations were found to be an important channel of dephasing for a single Josephson qubit.