Determination of Molecular Ground State via Short Square Pulses on Superconducting Qubits

Quantum computing is currently hindered by hardware noise. We present a freestyle superconducting pulse optimization method, incorporating two-qubit channels, that enhances flexibility, execution speed, and noise resilience. A minimal 0.22 ns pulse is shown to determine the H2 ground state to within chemical accuracy upon real hardware, approaching the quantum speed limit. Similarly, a pulse significantly shorter than circuit-based counterparts is found for the LiH molecule, attaining state-of-the-art accuracy. The method is general and can potentially accelerate performance across various quantum computing components and hardware.