Effects of higher levels of qubits on control of qubit protected by a Josephson quantum filter

Abstract A Josephson quantum filter (JQF) protects a data qubit (DQ) from the radiative decay into transmission lines (TLs) in superconducting computing architectures. transmon, which is weakly nonlinear harmonic oscillator rather than pure two-level system, can play role of JQF or DQ. However, previous study, and DQ were modeled as systems neglecting effects higher levels. We theoretically examine levels on control It shown that cause shift resonance frequency decrease maximum population first excited state controls with continuous wave (cw) field pulsed field, while do not. Moreover, we present optimal parameters maximize efficiency.