An array of four germanium qubits

A four-qubit quantum processor based on germanium hole spin quantum dots is presented. Universal quantum logic is demonstrated on qubits that are positioned in a two-by-two grid, revealing that spin qubits can be coupled in two dimensions.

Automated summary

This paper introduces a four-qubit quantum processor based on germanium hole spin quantum dots, demonstrating universal quantum logic on qubits arranged in a two-by-two grid and showing that spin qubits can be coupled in two dimensions.