Search for dissertations about: "Truncation"
Showing result 16 - 20 of 135 swedish dissertations containing the word Truncation.
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16. Extending the reach of uncertainty quantification in nuclear theory
Abstract : The theory of the strong interaction—quantum chromodynamics (QCD)—is unsuited to practical calculations of nuclear observables and approximate models for nuclear interaction potentials are required. In contrast to phenomenological models, chiral effective field theories (χEFTs) of QCD grant a handle on the theoretical uncertainty arising from the truncation of the chiral expansion. READ MORE
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17. On the efficiency of the Bayesian bootstrap
Abstract : The efficiency of the Bayesian bootstrap is treated for large and small samples from infinite and finite populations. The Bayesian bootstrap is compared with nonparametric and parametric Bayesian methods in the infinite case, for large samples and considering the mean and truncation functionals. READ MORE
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18. Efficient sampling of Bayesian posteriors and predictive distributions in χEFT
Abstract : In this thesis I employ Bayesian statistics to quantify parametric and epistemic uncertainties in chiral effective field theories (χEFT) and propagate these forward to predictions of observables in low-energy nuclear physics. Two primary sources of uncertainty---experimental errors and the theoretical error induced by the truncation of the EFT at up to next-to-next-to-leading-order---are modelled and accounted for in the posterior distributions of the unknown low-energy constants (LECs) that govern interaction strengths in χEFT. READ MORE
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19. A graded subring of an inverse limit of polynomial rings
Abstract : We study the power series ring R= K[[x1,x2,x3,...]]on countably infinitely many variables, over a field K, and two particular K-subalgebras of it: the ring S, which is isomorphic to an inverse limit of the polynomial rings in finitely many variables over K, and the ring R', which is the largest graded subalgebra of R. READ MORE
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20. Approximating the Three-Nucleon Continuum
Abstract : Three-nucleon forces (3NFs) are necessary to accurately describe the properties of atomic nuclei. These forces arise naturally together with two-nucleon forces (2NFs) when constructing nuclear interactions using chiral effective field theories (χEFTs) of quantum chromodynamics. READ MORE
