FQsun: A Configurable Wave Function-Based Quantum Emulator for Power-Efficient Quantum Simulations

Quantum computers are promising powerful computers for solving complex problems, but access to real quantum hardware remains limited due to high costs. Although software simulators like Qiskit, ProjectQ, and Pennylane offer flexibility and support for many qubits, they struggle with high power consumption and limited processing speed, particularly as qubit counts increase. Accordingly, quantum emulators implemented on dedicated hardware, such as FPGAs and analog circuits, offer a promising path for addressing energy efficiency concerns. However, existing studies on hardware-based emulators still face challenges in terms of limited flexibility and lack of fidelity evaluation. To overcome these gaps, we propose FQsun, a wave function-based quantum emulator that enhances performance by integrating four key innovations: efficient memory organization, a configurable Quantum Gate Unit (QGU), optimized scheduling, and five number precisions implemented on the Xilinx ZCU102. Experimental results demonstrate high fidelity, low mean square error, and high normalized gate speed, particularly with 32-bit versions. Benchmarking on Random Quantum Circuits, Quantum Fourier Transform, and Parameter-Shift Rule reveals that FQsun achieves a superior power-delay product and precisely, outperforms software simulators on CPUs in the processing speed range.