25 research outputs found
Efficient Algorithms for Universal Quantum Simulation
A universal quantum simulator would enable efficient simulation of quantum
dynamics by implementing quantum-simulation algorithms on a quantum computer.
Specifically the quantum simulator would efficiently generate qubit-string
states that closely approximate physical states obtained from a broad class of
dynamical evolutions. I provide an overview of theoretical research into
universal quantum simulators and the strategies for minimizing computational
space and time costs. Applications to simulating many-body quantum simulation
and solving linear equations are discussed
Dynamical modelling of the elliptical galaxy NGC 2974
In this paper we analyse the relations between a previously described oblate
Jaffe model for an ellipsoidal galaxy and the observed quantities for NGC 2974,
and obtain the length and velocity scales for a relevant elliptical galaxy
model. We then derive the finite total mass of the model from these scales, and
finally find a good fit of an isotropic oblate Jaffe model by using the
Gauss-Hermite fit parameters and the observed ellipticity of the galaxy NGC
2974. The model is also used to predict the total luminous mass of NGC 2974,
assuming that the influence of dark matter in this galaxy on the image,
ellipticity and Gauss-Hermite fit parameters of this galaxy is negligible
within the central region, of radius Comment: 7 figure
Quantum walks: a comprehensive review
Quantum walks, the quantum mechanical counterpart of classical random walks,
is an advanced tool for building quantum algorithms that has been recently
shown to constitute a universal model of quantum computation. Quantum walks is
now a solid field of research of quantum computation full of exciting open
problems for physicists, computer scientists, mathematicians and engineers.
In this paper we review theoretical advances on the foundations of both
discrete- and continuous-time quantum walks, together with the role that
randomness plays in quantum walks, the connections between the mathematical
models of coined discrete quantum walks and continuous quantum walks, the
quantumness of quantum walks, a summary of papers published on discrete quantum
walks and entanglement as well as a succinct review of experimental proposals
and realizations of discrete-time quantum walks. Furthermore, we have reviewed
several algorithms based on both discrete- and continuous-time quantum walks as
well as a most important result: the computational universality of both
continuous- and discrete- time quantum walks.Comment: Paper accepted for publication in Quantum Information Processing
Journa