Performance Assessment of Resonantly Driven Silicon Two-Qubit Quantum Gate

TL;DR

This paper theoretically analyzes the performance of resonantly driven silicon double quantum dot two-qubit gates, revealing how physical parameters influence gate speed and fidelity, and demonstrating promising scalability for quantum computing.

Contribution

It provides a detailed theoretical investigation of the physical mechanisms, scaling behaviors, and performance limits of silicon DQD-based resonantly driven two-qubit gates.

Findings

Gate delay can be less than 1 ns at ~10 nm spacing.

Entanglement strength exponentially depends on quantum dot spacing.

Gate fidelity remains reliable despite decoherence at small spacings.

Abstract

Two-qubit quantum gates play an essential role in quantum computing, whose operation critically depends on the entanglement between two qubits. Resonantly driven controlled-NOT (CNOT) gates based on silicon double quantum dots (DQDs) are studied theoretically. The physical mechanisms for effective gate modulation of the exchange coupling between two qubits are elucidated. Scaling behaviors of the singlet-triplet energy split, gate-switching speed, and gate fidelity are investigated as a function of the quantum dot spacing and modulation gate voltage. It is shown that the entanglement strength and gate-switching speed exponentially depend on the quantum dot spacing. A small spacing of ~10nm can promise a CNOT gate delay of <1 ns and reliable gate switching in the presence of decoherence. The results show promising performance potential of the resonantly driven two-qubit quantum gates based on aggressively scaled silicon DQDs.