Peter J. Love

A variational eigenvalue solver on a photonic quantum processor

Quantum computers promise to efficiently solve important problems that are intractable on a conventional computer. For quantum systems, where the physical dimension grows exponentially, finding the eigenvalues of certain operators is one such intractable problem and remains a fundamental challenge. The quantum phase estimation algorithm efficiently finds the eigenvalue of a given eigenvector but requires fully coherent evolution. Here we present an alternative approach that greatly reduces the requirements for coherent evolution and combine this method with a new approach to state preparation based on ansätze and classical optimization. We implement the algorithm by combining a highly reconfigurable photonic quantum processor with a conventional computer. We experimentally demonstrate the feasibility of this approach with an example from quantum chemistry—calculating the ground-state molecular energy for He–H+. The proposed approach drastically reduces the coherence time requirements, enhancing the potential of quantum resources available today and in the near future.

Realizable Hamiltonians for universal adiabatic quantum computers

It has been established that local lattice spin Hamiltonians can be used for universal adiabatic quantum computation. However, the two-local model Hamiltonians used in these proofs are general and hence do not limit the types of interactions required between spins. To address this concern, the present paper provides two simple model Hamiltonians that are of practical interest to experimentalists working toward the realization of a universal adiabatic quantum computer. The model Hamiltonians presented are the simplest known quantum-Merlin-Arthur-complete (QMA-complete) two-local Hamiltonians. The two-local Ising model with one-local transverse field which has been realized using an array of technologies, is perhaps the simplest quantum spin model but is unlikely to be universal for adiabatic quantum computation. We demonstrate that this model can be rendered universal and QMA-complete by adding a tunable two-local transverse

The Bravyi-Kitaev transformation for quantum computation of electronic structure

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Multipartite Quantum Entanglement Evolution in Photosynthetic Complexes

coupling. We also show the universality and QMA-completeness of spin models with only one-local

Lattice gas simulations of dynamical geometry in two dimensions

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Computational complexity in electronic structure

and

When is a quantum cellular automaton (QCA) a quantum lattice gas automaton (QLGA)

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Constructive quantum Shannon decomposition from Cartan involutions

fields and two-local

A particulate basis for a lattice-gas model of amphiphilic fluids

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From the Boltzmann equation to fluid mechanics on a manifold

interactions.