Tunable nonlinearity in superconducting resonators hosting Al/InAs nanowires

Nonlinear elements in superconducting circuits play a pivotal role in quantum applications, particularly for parametric amplifiers and quantum control of bosonic modes. Common sources of tunable nonlinearity are Josephson tunnel junctions arranged in a loop, for example in superconducting nonlinear asymmetric inductive elements (SNAILs), and high-kinetic-inductance superconducting thin films, in which the nonlinearity is controlled by magnetic flux and DC current, respectively. Gate-controlled superconducting-semiconducting hybrid devices, such as semiconducting Josephson junctions, are an alternative platform, promising the flexibility of the semiconductor-based electronics. The Andreev bound state physics, underlying the semiconducting junctions behavior, is highly nonlinear and has already been implemented in gatemon qubits, voltage-tunable resonators and parametric amplifiers. Here, we experimentally investigate the nonlinearity of a superconducting resonator comprising an aluminum (Al)-capped indium arsenide (InAs) nanowire hosting two Josephson junctions. Both the transmission, and the superconducting phase of the junctions can be tuned via gate and flux lines, and we show how both parameters affect the nonlinearity of the resonator. Finally, we discuss how the nonlinearity of the Andreev physics can be further exploited by reducing the distance between the junctions in the nanowire, moving towards Andreev molecules and multiterminal Josephson junctions.