28.10.2024Publication in Science on the hardness of quantum materials simulations

The simulation of quantum many-body systems with classical computers is a problem of exponential complexity in the size of the simulated system. Over the years, physicists have invented different algorithms to nevertheless address this problem and obtain meaningful results. The algorithms typically take advantage of the specific entanglement structure of quantum ground states. Particularly useful are variational approaches, which will always give a (hopefully tight) upper bound to the ground state energy, and can thus be vetted against each other. The researchers have developed a single measure, the v-score, that quantifies the hardness of a problem for a variational algorithm. In their publication in Science Magazin, the team provides accurate simulation results across many problems and techniques, that serve as a yardstick for testing new approaches and for novel algorithms running on quantum computers.