Lattice Hamiltonian in superconducting multi-qubit processors - Part 1

In multi-qubit systems, collective effects emerge due to qubit interactions, which significantly impact the performance and fidelity of quantum operations. However, these effects are often overlooked in models that consider only pairwise qubit-qubit interactions, leading to potential errors in gate operations and limiting scalability. Building on the recent concept of the Lattice Hamiltonian [1], we developed a Hamiltonian for surface code processors, focusing on stray interactions [2,3]. Our results indicate that multi-qubit interactions can dominate two-body interactions in certain quantum computing domains, providing insight into why two-qubit gate performance has seen limited improvement over the past decades.