Approximation based on perturbation theory is the foundation for most of the quantitative predictions of quantum mechanics with broad applications in quantum many-body physics. Quantum computing provides an alternative to the perturbation paradigm. In this talk, I will introduce a perturbative approach which combines the complementary strengths of the two approaches, enabling the simulation of large quantum systems using fewer quantum resources. The use of a quantum processor alleviates the need to identify a solvable unperturbed Hamiltonian, while the introduction of perturbative coupling permits a quantum processor to simulate systems with larger sizes. I will present an explicit perturbative expansion that mimics the Dyson series expansion and involves only local unitary operations. I will then discuss its optimality over other expansions under certain conditions. This perturbative approach is benchmarked by simulating the interacting dynamics of representative quantum systems.
Jinzhao Sun received his Ph.D. in physics from the University of Oxford, and received his B.Sc. in physics from Peking University. He joined Imperial College London in 2022 as a Research Associate. He has broad research interests in quantum computing, quantum many-body physics, quantum materials, and quantum information.