Search for dissertations about: "χEFT"

Showing result 1 - 5 of 6 swedish dissertations containing the word χEFT.

  2. 1. Making predictions using χEFT

    Author : Boris Karlsson; Chalmers tekniska högskola; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NN scattering; few-nucleon physics; nuclear physics; χEFT; uncertainty quantification;

    Abstract : In this thesis we explore the merits of chiral effective field theory (χEFT) as a model for low-energy nuclear physics. χEFT is an effective field theory based on quantum chromo dynamics (QCD) describing low-energy interactions of nucleons and pions. READ MORE

  4. 2. Efficient sampling of Bayesian posteriors and predictive distributions in χEFT

    Author : Isak Svensson; Chalmers tekniska högskola; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; chiral effective field theory; Bayesian parameter estimation; nuclear physics; Markov chain Monte Carlo; two-nucleon scattering;

    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

  5. 3. Extending the reach of uncertainty quantification in nuclear theory

    Author : Isak Svensson; Chalmers tekniska högskola; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES;

    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

  6. 4. Renormalization-Group Invariant Formulation of Chiral Effective Field Theory Applied to the Nucleon-Nucleon System

    Author : Oliver Thim; Chalmers tekniska högskola; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES;

    Abstract : Chiral effective field theory (χEFT) promises a systematically improvable description of the strong interaction between nucleons consistent with the symmetries of quantum chromodynamics (QCD). A sound power counting (PC) scheme is vital to organize the order-by-order contributions of interaction diagrams to nuclear observables in compliance with renormalization-group (RG) invariance. READ MORE

  7. 5. Approximating the Three-Nucleon Continuum

    Author : Sean Miller; Chalmers tekniska högskola; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES;

    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