Quantum\nNuclear Dynamics on a Distributed Set of Ion-Trap\nQuantum Computing Systems

Quantum nuclear dynamics with wavepacket\ntime evolution is classically\nintractable and viewed as a promising avenue for quantum information\nprocessing. Here, we use IonQ, Inc.’s 11-qubit trapped-ion\nquantum computer, Harmony, to study the quantum wavepacket dynamics\nof a shared-proton within a short-strong hydrogen-bonded system. We\nalso provide the first application of distributed quantum computing\nfor chemical dynamics problems, where a distributed set of quantum\nprocesses is constructed using a tensor network formalism. For a range\nof initial states, we experimentally drive the ion-trap system to\nemulate the quantum nuclear wavepacket as it evolves along the potential\nsurface generated from the electronic structure. Following the experimental\ncreation of the nuclear wavepacket, we extract measurement observables\nsuch as its time-dependent spatial projection and its characteristic\nvibrational frequencies to good agreement with classical results.\nVibrational eigenenergies obtained from quantum computation are in\nagreement with those obtained from classical simulations to within\na fraction of a kilocalorie per mole, thus suggesting chemical accuracy.\nOur approach opens a new paradigm for studying the quantum chemical\ndynamics and vibrational spectra of molecules and also provides the\nfirst demonstration of parallel quantum computation on a distributed\nset of ion-trap quantum computers.