Abstract: Recent demonstration of the first beyond classical quantum computation with a programmable superconducting quantum processor [1] opens the path to discovery of new quantum physics phenomena using these hardware systems. Gate model quantum computers used in [1] realize complex multi-qubit evolution in terms of discrete gates, elementary one and two qubit unitary operations, practically realized by a local time-dependent control Hamiltonian. In this talk we overview the recent many-body physics experiments implemented on these processors. We will specifically focus on the theory and experimental data describing quantum circuit kinetics in such systems, which answers the following question: how does a system initialized in a product state generate highly entangled states and in the case of a non-integrable system approach universal random matrix statistics? We characterize circuit kinetics using time-dependent evolution of out-of-time-order correlators (OTOC) and their ensemble variance. We demonstrate that dynamics of an ensemble average OTOC can be mapped onto a classical dynamical process akin to a population dynamics in biology. OTOC variance on the other hand is subject to a “sign problem” and therefore evades efficient classical description. We use ensemble average OTOC to verify hardware output, whereas OTOC variance provides a signature of operator entanglement generated in the system [2].
[1] Arute et. al. Nature, Vol 574, 505 (2019)
[2] Mi et. al. Science 2021 (10.1126/science.abg5029) arXiv:2101.08870
Location: ATL4402