Reminiscence of classical chaos in driven transmons

Transmon qubits are ubiquitously used in quantum information processing architectures based on superconducting circuits. Because of their lifetime, strong drives are required to realize fast, high-fidelity, gates and measurements, including parametrically activated processes. Here, we show that even off-resonant drives, in regimes routinely used in experiments, can cause strong modifications to the structure of the transmon spectrum rendering a large part of it chaotic. Accounting for the full nonlinear dynamics in a Floquet-Markov formalism, we find that the coherence time of the computational states of transmons can be significantly altered in the presence of a chaotic layer. In particular, chaos-assisted quantum phase slips greatly enhance band dispersions. In the presence of a measurement resonator, we find that approaching chaotic behavior correlates with strong transmon-resonator hybridization, and an average resonator response centered on the bare resonator frequency. The phenomena described here should be present in all circuits based on low-impedance Josephson-junctions