Quantum simulation and quantum-enhanced DFT

Density Functional Theory (DFT) is the workhorse of computational chemistry and materials modelling. In many cases, it successfully solves the many-body electronic structure problem without any need for quantum computers. But in other industrially important cases, DFT produces not just quantitatively but even qualitatively wrong answers. Meanwhile, quantum computation promises to provide accurate solutions to quantum many-body problems. But near-term quantum computers remain too small and noisy to be able to simulate meaningful systems. In this talk, I will present methods invented at Phasecraft along with numerical and early experimental results using data taken on Google’s hardware, which leverage the best of both worlds. We show that using small-scale, noisy quantum computation, we can enhance DFT’s ability to accurately solve large-scale many-body problems that conventional DFT struggles with.