scholarly journals Effective interactions in the sd and ρ shells

2020 ◽  
Vol 1 ◽  
pp. 168
Author(s):  
J. C. Varvitsiotis ◽  
L. D. Skouras
Keyword(s):  
Matrix Inversion ◽  
Complete Space ◽  
Effective Interactions ◽  
Inversion Techniques

Using matrix-inversion techniques effective interactions for the sd and ρ shells are determined in the complete space 0hω + 2hω. The derived interactions are used to determine the spectra of A =18-20 and A=5-15 nuclei and compare them with experiment.

MAXIMUM LIKELIHOOD FILTERING OF REFLECTION SEISMOGRAPH DATA

Geophysics ◽  
1978 ◽  
Vol 43 (3) ◽  
pp. 497-513 ◽  
Author(s):  
Edward Mercado
Keyword(s):  
Maximum Likelihood ◽  
Time Window ◽  
Wiener Filter ◽  
Matrix Inversion ◽  
Vertical Array ◽  
Array Data ◽  
Common Depth Point ◽  
Inversion Techniques

Two types of adaptive multichannel filters applied to exploration reflection seismograph data are the maximum likelihood filter and the Wiener filter. Derived equations for the two types of filters demonstrate that the maximum likelihood filter equations are identical in form to the Wiener equations and are solved by the same matrix inversion techniques. Application of the maximum likelihood filter to common‐depth‐point (CDP) data demonstrates that the output reflection quality is sensitive to reflection alignment on input traces. Presently, sufficient coherency of reflections on input traces can be achieved only on CDP traces with a time window in which the reflection signal is dominant or on vertical array data for which reflection alignment is straight‐forward.

scholarly journals Unfolding quantum computer readout noise

2020 ◽  
Vol 6 (1) ◽  
Author(s):  
Benjamin Nachman ◽  
Miroslav Urbanek ◽  
Wibe A. de Jong ◽  
Christian W. Bauer
Keyword(s):  
Nuclear Physics ◽  
High Energy Physics ◽  
Quantum Computer ◽  
Quantum Algorithm ◽  
High Energy ◽  
Matrix Inversion ◽  
Quantum Computers ◽  
Statistical Fluctuations ◽  
Inversion Techniques ◽  
Energy Physics

Abstract In the current era of noisy intermediate-scale quantum computers, noisy qubits can result in biased results for early quantum algorithm applications. This is a significant challenge for interpreting results from quantum computer simulations for quantum chemistry, nuclear physics, high energy physics (HEP), and other emerging scientific applications. An important class of qubit errors are readout errors. The most basic method to correct readout errors is matrix inversion, using a response matrix built from simple operations to probe the rate of transitions from known initial quantum states to readout outcomes. One challenge with inverting matrices with large off-diagonal components is that the results are sensitive to statistical fluctuations. This challenge is familiar to HEP, where prior-independent regularized matrix inversion techniques (“unfolding”) have been developed for years to correct for acceptance and detector effects, when performing differential cross section measurements. We study one such method, known as iterative Bayesian unfolding, as a potential tool for correcting readout errors from universal gate-based quantum computers. This method is shown to avoid pathologies from commonly used matrix inversion and least squares methods.

scholarly journals The Lagrangian hydrodynamics code magma2

2020 ◽  
Vol 498 (3) ◽  
pp. 4230-4255
Author(s):  
S Rosswog
Keyword(s):  
Substantial Reduction ◽  
Matrix Inversion ◽  
Blast Waves ◽  
Finite Volume Schemes ◽  
Benchmark Tests ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
Lagrangian Hydrodynamics ◽  
And Performance ◽  
Inversion Techniques

ABSTRACT We present the methodology and performance of the new Lagrangian hydrodynamics code magma2, a smoothed particle hydrodynamics (SPH) code that benefits from a number of non-standard enhancements. By default it uses high-order smoothing kernels and wherever gradients are needed, they are calculated via accurate matrix inversion techniques, but a more conventional formulation with kernel gradients has also been implemented for comparison purposes. We also explore a matrix inversion formulation of SPH with a symmetrization in the particle indices that is not frequently used. We find interesting advantages of this formulation in some of the tests, for example, a substantial reduction of surface tension effects for non-ideal particle setups and more accurate peak densities in Sedov blast waves.  magma2 uses artificial viscosity, but enhanced by techniques that are commonly used in finite-volume schemes such as reconstruction and slope limiting. While simple to implement, this approach efficiently suppresses particle noise, but at the same time drastically reduces dissipation in locations where it is not needed and actually unwanted. We demonstrate the performance of the new code in a number of challenging benchmark tests including, for example, multidimensional vorticity creating Schulz–Rinne-type Riemann problems and more astrophysical tests such as a collision between two stars to demonstrate its robustness and excellent conservation properties.

EFFECTIVE INTERACTIONS AND THE EXCITATION OF GIANT RESONANCES

1984 ◽  
Vol 45 (C4) ◽  
pp. C4-231-C4-249
Author(s):  
W. G. Love ◽  
M. A. Franey
Keyword(s):  
Giant Resonances ◽  
Effective Interactions

Effective Interactions Approach to Phase Stability in Alloys Under Irradiation

1998 ◽  
Vol 538 ◽  
Author(s):  
Raúl A. Enrique ◽  
Pascal Bellon
Keyword(s):  
Phase Diagram ◽  
Phase Stability ◽  
Kinetic Monte Carlo ◽  
Theoretical Frameworks ◽  
Effective Interactions ◽  
Dynamical Phase ◽  
Thermodynamic Potentials ◽  
Simple Kinetic Model ◽  
Kinetic Monte Carlo Simulations ◽  
Competing Dynamics

AbstractPhase stability in alloys under irradiation is studied considering effective thermodynamic potentials. A simple kinetic model of a binary alloy with phase separation is investigated. Time evolution in the alloy results from two competing dynamics: thermal diffusion, and irradiation induced ballistic exchanges. The dynamical (steady state) phase diagram is evaluated exactly performing Kinetic Monte Carlo simulations. The solution is then compared to two theoretical frameworks: the effective quasi-interactions model as proposed by Vaks and Kamishenko, and the effective free energy model as proposed by Martin. New developments of these models are proposed to allow for quantitative comparisons. Both theoretical frameworks yield fairly good approximations to the dynamical phase diagram.

Inversion Techniques Applied in Stratigraphic Interpretation

1990 ◽  
Vol 45 (3) ◽  
pp. 345-355
Author(s):  
J. Helgesen ◽  
I. Brevik ◽  
E. Berg
Keyword(s):  
Inversion Techniques
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