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Application of the maximum entropy method to dynamical fermion simulations. / Jonathan Clowser

Swansea University Author: Jonathan Clowser

Abstract

This thesis presents results for spectral functions extracted from imaginary-time correlation functions obtained from Monte Carlo simulations using the Maximum Entropy Method (MEM). The advantages this method are (i) no a priori assumptions or parametrisations of the spectral function are needed, (i...

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Published: 2002
Institution: Swansea University
Degree level: Doctoral
Degree name: Ph.D
URI: https://cronfa.swan.ac.uk/Record/cronfa42282
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last_indexed 2018-08-03T10:09:44Z
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spelling 2018-08-02T16:24:28.6825969 v2 42282 2018-08-02 Application of the maximum entropy method to dynamical fermion simulations. 6445d9f4696a978703f3e90f6df29437 NULL Jonathan Clowser Jonathan Clowser true true 2018-08-02 This thesis presents results for spectral functions extracted from imaginary-time correlation functions obtained from Monte Carlo simulations using the Maximum Entropy Method (MEM). The advantages this method are (i) no a priori assumptions or parametrisations of the spectral function are needed, (ii) a unique solution exists and (iii) the statistical significance of the resulting image can be quantitatively analysed. The Gross Neveu model in d = 3 spacetime dimensions (GNM3) is a particularly interesting model to study with the MEM because at T = 0 it has a broken phase with a rich spectrum of mesonic bound states and a symmetric phase where there are resonances. Results for the elementary fermion, the Goldstone boson (pion), the sigma, the massive pseudoscalar meson and the symmetric phase resonances are presented. UKQCD Nf = 2 dynamical QCD data is also studied with MEM. Results are compared to those found from the quenched approximation, where the effects of quark loops in the QCD vacuum are neglected, to search for sea-quark effects in the extracted spectral functions. Information has been extract from the difficult axial spatial and scalar as well as the pseudoscalar, vector and axial temporal channels. An estimate for the non-singlet scalar mass in the chiral limit is given which is in agreement with the experimental value of Mao = 985 MeV. E-Thesis Theoretical physics. 31 12 2002 2002-12-31 COLLEGE NANME Physics COLLEGE CODE Swansea University Doctoral Ph.D 2018-08-02T16:24:28.6825969 2018-08-02T16:24:28.6825969 Faculty of Science and Engineering School of Biosciences, Geography and Physics - Physics Jonathan Clowser NULL 1 0042282-02082018162442.pdf 10797990.pdf 2018-08-02T16:24:42.1930000 Output 9641968 application/pdf E-Thesis true 2018-08-02T16:24:42.1930000 false
title Application of the maximum entropy method to dynamical fermion simulations.
spellingShingle Application of the maximum entropy method to dynamical fermion simulations.
Jonathan Clowser
title_short Application of the maximum entropy method to dynamical fermion simulations.
title_full Application of the maximum entropy method to dynamical fermion simulations.
title_fullStr Application of the maximum entropy method to dynamical fermion simulations.
title_full_unstemmed Application of the maximum entropy method to dynamical fermion simulations.
title_sort Application of the maximum entropy method to dynamical fermion simulations.
author_id_str_mv 6445d9f4696a978703f3e90f6df29437
author_id_fullname_str_mv 6445d9f4696a978703f3e90f6df29437_***_Jonathan Clowser
author Jonathan Clowser
author2 Jonathan Clowser
format E-Thesis
publishDate 2002
institution Swansea University
college_str Faculty of Science and Engineering
hierarchytype
hierarchy_top_id facultyofscienceandengineering
hierarchy_top_title Faculty of Science and Engineering
hierarchy_parent_id facultyofscienceandengineering
hierarchy_parent_title Faculty of Science and Engineering
department_str School of Biosciences, Geography and Physics - Physics{{{_:::_}}}Faculty of Science and Engineering{{{_:::_}}}School of Biosciences, Geography and Physics - Physics
document_store_str 1
active_str 0
description This thesis presents results for spectral functions extracted from imaginary-time correlation functions obtained from Monte Carlo simulations using the Maximum Entropy Method (MEM). The advantages this method are (i) no a priori assumptions or parametrisations of the spectral function are needed, (ii) a unique solution exists and (iii) the statistical significance of the resulting image can be quantitatively analysed. The Gross Neveu model in d = 3 spacetime dimensions (GNM3) is a particularly interesting model to study with the MEM because at T = 0 it has a broken phase with a rich spectrum of mesonic bound states and a symmetric phase where there are resonances. Results for the elementary fermion, the Goldstone boson (pion), the sigma, the massive pseudoscalar meson and the symmetric phase resonances are presented. UKQCD Nf = 2 dynamical QCD data is also studied with MEM. Results are compared to those found from the quenched approximation, where the effects of quark loops in the QCD vacuum are neglected, to search for sea-quark effects in the extracted spectral functions. Information has been extract from the difficult axial spatial and scalar as well as the pseudoscalar, vector and axial temporal channels. An estimate for the non-singlet scalar mass in the chiral limit is given which is in agreement with the experimental value of Mao = 985 MeV.
published_date 2002-12-31T03:52:39Z
_version_ 1763752605103685632
score 11.013799

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