A unified quantum computing quantum Monte Carlo framework through structured state preparation

Quantum Computing Quantum Monte Carlo (QCQMC) has been expanded to estimate excited-state spectra, moving beyond its original purpose of ground-state energy estimation. This advancement is achieved by replacing the Variational Quantum Eigensolver (VQE) with task-adapted unitaries, allowing for more flexible state preparation. The new framework enables QCQMC to address excited-state spectra through Variational Fast Forwarding and the Variational Unitary Matrix Product. This development has significant implications for quantum computing, as it increases the versatility of QCQMC and enables its application to a broader range of problems¹. The ability to estimate excited-state spectra is crucial in various fields, including chemistry and materials science. As quantum computing continues to advance, its potential applications extend beyond the immediate target, raising the stakes from criminal to geopolitical. This matters to practitioners because it highlights the need to consider the broader implications of quantum computing advancements on national security and global stability.