Characterisation of an exchange-based two-qubit gate for resonant exchange qubits

TL;DR

This paper analyzes a proposed two-qubit gate for resonant exchange qubits in semiconductor quantum dots, demonstrating high fidelity and fast operation under realistic noise conditions, supporting their viability for quantum computing.

Contribution

The paper provides detailed analysis and simulations of a novel two-qubit gate for resonant exchange qubits, showing it can achieve high fidelity with realistic noise levels.

Findings

Gate errors at the percent level under experimental noise conditions

Gate times comparable to single-qubit operations

High fidelity implementation feasible with current technology

Abstract

Resonant exchange qubits are a promising addition to the family of experimentally implemented encodings of single qubits using semiconductor quantum dots. We have shown previously that it ought to be straightforward to perform a CPHASE gate between two resonant exchange qubits with a single exchange pulse. This approach uses energy gaps to suppress leakage rather than conventional pulse sequences. In this paper we present analysis and simulations of our proposed two-qubit gate subject to charge and Overhauser field noise at levels observed in current experiments. Our main result is that we expect implementations of our two-qubit gate to achieve high fidelities, with errors at the percent level and gate times comparable to single-qubit operations. As such, exchange-coupled resonant exchange qubits remain an attractive approach for quantum computing.