Engineering Strong Beamsplitter Interaction between Bosonic Modes via Quantum Optimal Control Theory

Understand

In continuous-variable quantum computing with qubits encoded in the infinite-dimensional Hilbert space of bosonic modes, it is a difficult task to realize strong and on-demand interactions between the qubits.

• One option is to engineer a beamsplitter interaction for photons in two superconducting cavities by driving an intermediate superconducting circuit with two continuous-wave drives, as demonstrated in a recent experiment.
• Here, we show how quantum optimal control theory (OCT) can be used in a systematic way to improve the beamsplitter interaction between the two cavities.
• We find that replacing the two-tone protocol by a three-tone protocol accelerates the effective beamsplitter rate between the two cavities.