Study of linear response in Hubbard chains using Many-body Perturbation Theory

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Show simple item record Bostan, Irina 2011-02-25T06:43:13Z 2011-02-25T06:43:13Z 2010
dc.identifier.uri en
dc.description.abstract In this work the basic formalism of non-equilibrium Green’s functions is presented and then applied to study a Ward identity in linear response theory, namely the frequency sum-rule. It can be proven that the frequency sum-rule is satisfied when the quantities involved are calculated using perturbation theory within a conserving approximation for the self-energy. To illustrate this equality along with other properties of the response function, a numerical application that solves the Kadanoff-Baym equations for systems of Hubbard chains was used. The results showed that the frequency sum-rule was satisfied to the same extent by all the conserving approximations used as by the exact diagonalization numerical results. The density response function was analyzed diagrammatically for a series of conserving approximations for the self-energy and this demonstrated that even for a first order in perturbation theory approximation for the self-energy, the response function has a corresponding complex, third order in the perturbation diagrammatic structure.
dc.format.extent 46 sivua
dc.language.iso eng
dc.rights This publication is copyrighted. You may download, display and print it for Your own personal use. Commercial use is prohibited. en
dc.rights Julkaisu on tekijänoikeussäännösten alainen. Teosta voi lukea ja tulostaa henkilökohtaista käyttöä varten. Käyttö kaupallisiin tarkoituksiin on kielletty. fi
dc.rights openAccess fi
dc.subject.other condensed matter
dc.subject.other many-body theory
dc.title Study of linear response in Hubbard chains using Many-body Perturbation Theory
dc.identifier.urn URN:NBN:fi:jyu-201102251820
dc.type.dcmitype Text en
dc.type.ontasot Pro gradu fi
dc.type.ontasot Master’s thesis en
dc.contributor.tiedekunta matemaattis-luonnontieteellinen tiedekunta fi
dc.contributor.tiedekunta Faculty of Sciences en
dc.contributor.laitos fysiikan laitos fi
dc.contributor.laitos Department of Physics en
dc.contributor.yliopisto University of Jyväskylä en
dc.contributor.yliopisto Jyväskylän yliopisto fi
dc.contributor.oppiaine fysiikka fi
dc.contributor.oppiaine Physics en

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