Improving Emulation of Quantum Algorithms using Space-Efficient Hardware Architectures

With rapid advancement in quantum computing technology, continuous efforts are being directed to simulation and emulation of quantum algorithms on classical platforms. A well-known limitation to classical emulation of quantum circuits is scalability. Existing hardware emulators implement gate-based circuit models of quantum circuits that result in heavy resource utilization and degrade the scalability of the system. Also, current quantum emulation hardware use fixedpoint arithmetic, which has an adverse effect on accuracy when the system is scaled up. In this work, we employ a complexmultiply-and-accumulate (CMAC) and lookup-based emulation approach that greatly reduces resource utilization and improves system scalability in terms of number of emulated qubits. We demonstrate emulation of up to 16 fully-entangled qubits which is highest among existing work. We design fully-pipelined, highthroughput hardware architectures that use floating-point precision for higher accuracy. Experimental evaluation and analysis of the architectures in terms of speed and area is also provided. The emulator is prototyped on a high-performance reconfigurable computing (HPRC) system and our results demonstrate quantitative improvement over existing Field-Programmable-Gate-Array (FPGA)-based hardware emulators.