MCOPI · Multi-Chip 0- π Qubit Distribution: A Feasible Frontier in Quantum Computing?

The pursuit of scalable quantum computing requires groundbreaking solutions to overcome noise, high error rates, and the limited qubit counts of existing architectures. The 0-π (zero-pi) qubit, with its intrinsic protection against environmental noise, offers a transformative path toward fault-tolerant quantum computing, demonstrating superior coherence times compared to conventional superconducting qubits like the transmon. Despite recent advancements, a fully protected version—the hard 0-π qubit—remains unrealized, and the integration of these qubits into scalable, distributed architectures presents a critical, unresolved challenge.This proposal seeks to experimentally demonstrate the hard 0-π qubit and develop a modular, multi-chip quantum processing unit (QPU) architecture. We will investigate and mitigate the decoherence mechanisms, optimize the qubit’s design for enhanced coherence, and implement a high-fidelity interconnect system to seamlessly link qubits across chips. Utilizing advanced 3D integration and flip-chip technology, our scalable architecture will be engineered to support large quantum systems with unparalleled noise resilience and coherence stability.By combining a novel qubit design with state-of-the-art packaging technology, this project aims to lay the foundation for the first scalable, noise-resilient quantum computing platform powered by 0-π qubits. This breakthrough has the potential to unlock new frontiers in fault-tolerant quantum systems, enabling impactful applications across fields such as quantum chemistry, secure communication, and optimization problems. Ultimately, the project aspires to position Europe at the forefront of global quantum technology development.