QuASI: Qubit Accessible Simulation Interface for Source-Agnostic Time-Domain Control Signals

Quantum computing promises breakthroughs in solving challenging problems beyond the reach of classical machines. Achieving quantum advantage with millions of physical qubits requires advanced qubit-control circuitry, but designing and testing such systems remains costly and slow due to limited access to dilution refrigerators. While commercial quantum simulation software can reduce reliance on physical qubit experiments, models that capture qubit behavior under arbitrary pulse shapes are still lacking. We present QuASI, a qubit digital twin that simulates open quantum system dynamics and generates qubit response to source-agnostic control pulses. QuASI accepts simulated inputs from Electronic Design Automation (EDA) tools and measured data of qubit controllers, accelerating research in control schemes. In particular, QuASI calculates qubit energy-state evolution from time-domain pulses generated by circuit simulations of our custom cryogenic integrated controllers and compares them with theoretical predictions. We also use pulse-shape optimization algorithms for hardware calibration through Fourier-domain analysis. By enabling co-simulation with EDA tools, QuASI lowers the development costs of qubit controllers and accelerates progress toward scalable quantum processors.