The Experts below are selected from a list of 62145 Experts worldwide ranked by ideXlab platform

Ashley Montanaro - One of the best experts on this subject based on the ideXlab platform.

  • Quantum computational supremacy
    Nature, 2017
    Co-Authors: Aram W. Harrow, Ashley Montanaro
    Abstract:

    The field of quantum algorithms aims to find ways to speed up the solution of computational problems by using a quantum Computer. A key milestone in this field will be when a universal quantum Computer performs a computational task that is beyond the capability of any Classical Computer, an event known as quantum supremacy. This would be easier to achieve experimentally than full-scale quantum computing, but involves new theoretical challenges. Here we present the leading proposals to achieve quantum supremacy, and discuss how we can reliably compare the power of a Classical Computer to the power of a quantum Computer. Proposals for demonstrating quantum supremacy, when a quantum Computer supersedes any possible Classical Computer at a specific task, are reviewed.

Peter Nyman - One of the best experts on this subject based on the ideXlab platform.

Maciej Lewenstein - One of the best experts on this subject based on the ideXlab platform.

  • Hybrid annealing: Coupling a quantum simulator to a Classical Computer
    Physical Review A, 2017
    Co-Authors: Tobias Graß, Maciej Lewenstein
    Abstract:

    Finding the global minimum in a rugged potential landscape is a computationally hard task, often equivalent to relevant optimization problems. Annealing strategies, either Classical or quantum, explore the configuration space by evolving the system under the influence of thermal or quantum fluctuations. The thermal annealing dynamics can rapidly freeze the system into a low-energy configuration, and it can be simulated well on a Classical Computer, but it easily gets stuck in local minima. Quantum annealing, on the other hand, can be guaranteed to find the true ground state and can be implemented in modern quantum simulators; however, quantum adiabatic schemes become prohibitively slow in the presence of quasidegeneracies. Here, we propose a strategy which combines ideas from simulated annealing and quantum annealing. In such a hybrid algorithm, the outcome of a quantum simulator is processed on a Classical device. While the quantum simulator explores the configuration space by repeatedly applying quantum fluctuations and performing projective measurements, the Classical Computer evaluates each configuration and enforces a lowering of the energy. We have simulated this algorithm for small instances of the random energy model, showing that it potentially outperforms both simulated thermal annealing and adiabatic quantum annealing. It becomes most efficient for problems involving many quasidegenerate ground states.

Valery S. Shchesnovich - One of the best experts on this subject based on the ideXlab platform.

  • Sufficient condition for the mode mismatch of single photons for scalability of the boson-sampling Computer
    Physical Review A, 2014
    Co-Authors: Valery S. Shchesnovich
    Abstract:

    The boson sampler proposed by Aaronson and Arkhipov is a nonuniversal quantum Computer, which can serve as evidence against the extended Church-Turing thesis. It samples the probability distribution at the output of a linear unitary optical network with indistinguishable single photons at the input. Four experimental groups have already tested their small-scale prototypes with up to four photons. A boson sampler with a few dozens of single photons is believed to be hard to simulate on a Classical Computer. For scalability of a realistic boson sampler with current technology it is necessary to know the effect of the photon mode mismatch on its operation. Here a nondeterministic model of the boson sampler is analyzed, which employs partially indistinguishable single photons emitted by identical sources. A sufficient condition on the average mutual fidelity $\ensuremath{\langle}\mathcal{F}\ensuremath{\rangle}$ of the single photons is found, which guarantees that the realistic boson sampler outperforms the Classical Computer. Moreover, the boson-sampler Computer with partially indistinguishable single photons is scalable and has more power than Classical Computers when the single-photon mode mismatch $1\ensuremath{-}\ensuremath{\langle}\mathcal{F}\ensuremath{\rangle}$ scales as $O({N}^{\ensuremath{-}3/2})$ with the total number of photons $N$.

Aram W. Harrow - One of the best experts on this subject based on the ideXlab platform.

  • Quantum computational supremacy
    Nature, 2017
    Co-Authors: Aram W. Harrow, Ashley Montanaro
    Abstract:

    The field of quantum algorithms aims to find ways to speed up the solution of computational problems by using a quantum Computer. A key milestone in this field will be when a universal quantum Computer performs a computational task that is beyond the capability of any Classical Computer, an event known as quantum supremacy. This would be easier to achieve experimentally than full-scale quantum computing, but involves new theoretical challenges. Here we present the leading proposals to achieve quantum supremacy, and discuss how we can reliably compare the power of a Classical Computer to the power of a quantum Computer. Proposals for demonstrating quantum supremacy, when a quantum Computer supersedes any possible Classical Computer at a specific task, are reviewed.