  Parametric conversion and amplification based on three-wave mixing are
powerful primitives for efficient quantum operations. For superconducting
qubits, such operations can be realized with a quadrupole Josephson junction
element, the Josephson Ring Modulator (JRM), which behaves as a loss-less
three-wave mixer. However, combining multiple quadrupole elements is a
difficult task so it would be advantageous to have a pure three-wave dipole
element that could be tessellated for increased power handling and/or
information throughput. Here, we present a dipole circuit element with
third-order nonlinearity, which implements three-wave mixing. Experimental
results for a non-degenerate amplifier based on the proposed pure third-order
nonlinearity are reported.
