title: Hamiltonian learning and certification using quantum resources.
abstract: In recent years quantum simulation has made great strides, culminating in experiments that existing supercomputers cannot easily simulate. Although this raises the possibility that special purpose analog quantum simulators may be able to perform computational tasks that existing computers cannot, it also introduces a major challenge: certifying that the quantum simulator is in fact simulating the correct quantum dynamics. We provide an algorithm that, under relatively weak assumptions, can be used to efficiently infer the Hamiltonian of a large but untrusted quantum simulator using a trusted quantum simulator. We illustrate the power of this approach by showing numerically that it can inexpensively learn the Hamiltonians for large frustrated Ising models, demonstrating that quantum resources can make certifying analog quantum simulators tractable.
authors.affiliation: Quantum Architectures and Computation Group, Microsoft Research, Redmond, Washington 98052, USA and Department of Combinatorics & Optimization, University of Waterloo, Ontario N2L 3G1, Canada and Institute for Quantum Computing, University of Waterloo, Ontario N2L 3G1, Canada.
authors.forename: Nathan
authors.initials: N
authors.lastname: Wiebe
authors.affiliation: Institute for Quantum Computing, University of Waterloo, Ontario N2L 3G1, Canada and Department of Physics, University of Waterloo, Ontario N2L 3G1, Canada.
authors.forename: Christopher
authors.initials: C
authors.lastname: Granade
authors.affiliation: Center for Quantum Information and Control, University of New Mexico, Albuquerque, New Mexico 87131-0001, USA.
authors.forename: Christopher
authors.initials: C
authors.lastname: Ferrie
authors.affiliation: Institute for Quantum Computing, University of Waterloo, Ontario N2L 3G1, Canada and Department of Chemistry, University of Waterloo, Ontario N2L 3G1, Canada and Perimeter Institute, University of Waterloo, Ontario N2L 2Y5, Canada.
authors.forename: D G
authors.initials: DG
authors.lastname: Cory