Dynamically Reconfigurable Photon Exchange in a Superconducting Quantum Processor

TL;DR

This paper introduces a reconfigurable photon exchange network embedded in a superconducting quantum processor, enabling long-range, high-fidelity qubit interactions and paving the way for scalable, modular quantum computing.

Contribution

It presents a novel on-chip photonic network that achieves reconfigurable, long-range qubit connectivity in a superconducting quantum processor, enhancing scalability.

Findings

Achieved photon exchange rates up to 2π × 0.9 MHz.

Demonstrated long-range qubit interactions over 9.2 cm.

Enabled reconfigurable qubit connectivity graph.

Abstract

Realizing the advantages of quantum computation requires access to the full Hilbert space of states of many quantum bits (qubits). Thus, large-scale quantum computation faces the challenge of efficiently generating entanglement between many qubits. In systems with a limited number of direct connections between qubits, entanglement between non-nearest neighbor qubits is generated by a series of nearest neighbor gates, which exponentially suppresses the resulting fidelity. Here we propose and demonstrate a novel, on-chip photon exchange network. This photonic network is embedded in a superconducting quantum processor (QPU) to implement an arbitrarily reconfigurable qubit connectivity graph. We show long-range qubit-qubit interactions between qubits with a maximum spatial separation of $9.2~\text{cm}$ along a meandered bus resonator and achieve photon exchange rates up to $g_{\text{qq}} = 2\pi \times 0.9~\text{MHz}$. These experimental demonstrations provide a foundation to realize highly connected, reconfigurable quantum photonic networks and opens a new path towards modular quantum computing.