Perturbative analysis of quasiperiodic patterning of transmon quantum computers: Enhancement of many-body localization

Recently, it has been shown that transmon qubit architectures experience a transition between many-body localized and quantum chaotic phases. While it is crucial for quantum computation that the system remains in the localized regime, the most common way to achieve this has been relying on disorder in Josephson junction parameters. Here, we propose a quasiperiodic patterning of parameters as a substitute for random disorder. We demonstrate, using the Walsh-Hadamard diagnostic, that quasiperiodicity is more effective than disorder for achieving localization. To study the localizing properties of our Hamiltonian for large, experimentally relevant system sizes, we use two complementary perturbation theory schemes, one with respect to the many-body interactions and one with respect to the hopping parameter of the free Hamiltonian.