Chu leads the Hybrid Quantum Systems Group coupling mechanical resonators to superconducting circuits and diamond color centers. Research directions: (1) Circuit quantum acousto-dynamics (cQAD) — HBAR resonators coupled to transmon qubits achieve single-phonon nonlinearity (coherence/anharmonicity ratio 6.8), mechanical qubit gates demonstrated (arXiv 2406.07360, 2024); (2) Optimal control for high Fock state preparation in bulk resonators; (3) Ultra-cold mechanical quantum sensor — cryogenically cooled nanomechanical oscillators as probes for new physics beyond the standard model; (4) Coupling NV/SiV color centers in diamond to acoustic waves for hybrid quantum memory and transduction. Targets long-lived phonon storage for quantum networking and quantum sensing beyond the standard quantum limit.