Modular quantum processor with an all-to-all reconfigurable router

Physical Review X (2024)

 

Superconducting qubits are one of the leading technologies for building quantum computers, but they usually connect to only a few nearby qubits. Making longer-range connections between qubits is useful, especially for modern error-correcting codes, but it often requires complex hardware setups, which can be costly and reduce performance.

In this paper, a research team created a quantum processor with reconfigurable, all-to-all connectivity — meaning any qubit can connect to any other qubit, as needed. The processor is modular, made up of two separate chips (each holding two qubits) that are mounted on a shared base.

The group demonstrated controlled-Z quantum gates (a type of operation that entangles two qubits) between all pairs of qubits, with an average fidelity of 96%. Using their modular processor, they generated entangled states involving three and four qubits, achieving fidelities of 88.15% for three qubits and 75.18% for four qubits.

This modular approach simplifies the creation of flexible and scalable quantum processors with better connectivity between qubits. It provides a practical way to build larger quantum computers and run advanced algorithms and error-correction methods more efficiently.

The paper’s authors are Xuntao Wu, Haoxiong Yan, Gustav Andersson, Alexander Anferov, Ming-Han Chou, Christopher Conner, Joel Grebel, Yash Joshi, Shiheng Li, Jacob Miller, Hong Qiao and Andrew Cleland, conducting their work at the University of Chicago and Argonne National Laboratory.