A novel unitary quantum lattice algorithm is developed to explore quantum turbulence. Because of its low memory requirements and its near perfect parallelization to the full 12,288 cores on the Cray XT5, simulations w...
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A novel unitary quantum lattice algorithm is developed to explore quantum turbulence. Because of its low memory requirements and its near perfect parallelization to the full 12,288 cores on the Cray XT5, simulations were run up to spatial grids of 5,7603. The Gross-Pitaevskii equation, which describes the ground state of a Bose Einstein condensate (BEC), is solved and it is found that the incompressible kinetic energy spectrum exhibits 3 distinct power laws: classical Kolmogorov k -5/3 spectrum at scales much larger than the individual quantum vortex cores, and a quantum Kelvin wave cascade spectrum of k -3 at scales of the order of the quantum cores. In the adjoining semiclassical regime, there is a steeper spectral decay transitioning between the classical and quantum regimes. However, its spectral exponent does not seem to be universal. This is the first, first-principle simulation yielding the universal quantum Kelvin cascade exponent.
In FY2008, the U.S. Department of Defense (DoD) initiated the Computational Research and Engineering Acquisition Tools and Environments (CREATE) program, a $360M program with a two-year planning phase and a ten-year e...
Lattice Boltzmann algorihms are a mesoscopic representation of nonlinear continuum physics (like Navier-Stokes, magnetohydrodynamics (MHD), Gross-Pitaevskii equations) which are ideal for parallel supercomputers becau...
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Lattice Boltzmann algorihms are a mesoscopic representation of nonlinear continuum physics (like Navier-Stokes, magnetohydro dynamics (MHD), Gross- Pitaevskii equations) which are ideal for parallel supercomputers bec...
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Lattice Boltzmann algorihms are a mesoscopic representation of nonlinear continuum physics (like Navier-Stokes, magnetohydro dynamics (MHD), Gross- Pitaevskii equations) which are ideal for parallel supercomputers because they transform the difficult nonlinear convective macroscopic derivatives into purely local moments of distribution functions. The macroscopic nonlinearities are recovered by relaxation distribution functions in the collision operator whose dependence on the macroscopic velocity is algebraically nonlinear and thus purely local. Unlike standard computational fluid dynamics codes, there is no loss in parallelization in handling arbitrary geometric boundaries, e.g., using bounce-back rules from kinetic theory. By encoding detailed balance into the collision operator through the introduction of discrete H-function, the lattice Boltzmann algorithm can be made unconditionally stable for arbitrary high Reynolds numbers. It is shown that this approach is a special case of a quantum lattice Boltzmann algorithm that entangles local qubits through unitary collision operators and which is ideally parallelized on quantum computer architectures. Here we consider turbulence simulations using 2,048 PEs on a 1,6003-spatial grid. A connection is found between the rate of change of enstrophy and the onset of laminar-to- turbulent flows.
In this paper, a systematic study of the effects of complexity of prediction methodology on its accuracy for a set of real applications on a variety of HPC systems is performed. Results indicate that the use of any si...
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Seven application programs were used in the Technology Insertion for 2003 benchmark testing process to determine what new high-performancecomputing capability should be procured. One of the most intensive parts of en...
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Seven application programs were used in the Technology Insertion for 2003 benchmark testing process to determine what new high-performancecomputing capability should be procured. One of the most intensive parts of engineering and scientific computations is the solution of a simultaneous, linear system of equations. We survey the seven benchmark application programs for what linear solvers are used and where they originated.
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