Multipartite Entanglement in Rabi-Driven Superconducting Qubits
Marie Lu, Jean-Loup Ville, Joachim Cohen, Alexandru Petrescu, Sydney Schreppler, Larry Chen, Christian Jünger, Chiara Pelletti, Alexei Marchenkov, Archan Banerjee, William P. Livingston, John Mark Kreikebaum, David Santiago, Alexandre Blais, Irfan Siddiqi
Abstract
The exploration of highly connected networks of qubits is invaluable for implementing various quantum algorithms and simulations, as it allows for entangling qubits with reduced circuit depth. Here, we demonstrate a multiqubit sideband tone-assisted Rabi-driven gate. Our scheme is inspired by the ion-qubit Mlmer-Srensen gate and is mediated by a shared photonic mode and Rabi-driven superconducting qubits, which relaxes restrictions on qubit frequencies during fabrication and supports scalability. We achieve a two-qubit gate with a maximum state fidelity of 95% in 310 ns, a three-qubit gate with a state fidelity of 90.5% in 217 ns, and a four-qubit gate with a state fidelity of 66% in 200 ns. Furthermore, we develop a model of the gate that shows that the four-qubit gate is limited by shared resonator losses and the spread of qubit-resonator couplings, which must be addressed to reach high-fidelity operations.