Long-Range Interaction between Charge and Spin Qubits in Quantum Dots

TL;DR

This paper investigates the potential for long-range capacitive coupling between various spin qubits in quantum dots via floating metallic gates, highlighting hybrid qubits as promising for scalable quantum computing.

Contribution

It provides estimates and analysis of long-distance coupling between different spin qubits across multiple materials, emphasizing hybrid qubits' suitability for scalable quantum gates.

Findings

Hybrid qubits can be strongly capacitively coupled at small distances.

Long-range coupling enables two-qubit gate implementation.

Hybrid qubits are promising for scalable quantum computing.

Abstract

We analyze and give estimates for the long-distance coupling via floating metallic gates between different types of spin qubits in quantum dots made of different commonly used materials. In particular, we consider the hybrid, the singlet-triplet, and the spin-$1/2$ qubits, and the pairwise coupling between each type of these qubits with another hybrid qubit in GaAs, InAs, Si, and $\mathrm{Si_{0.9}Ge_{0.1}}$. We show that hybrid qubits can be capacitively coupled strongly enough to implement two-qubit gates, as long as the distance of the dots from the metallic gates is small enough. Thus, hybrid qubits are good candidates for scalable implementations of quantum computing in semiconducting nanostructures.