Diagrammatic Monte Carlo study of the Holstein polaron

Ragni, Stefano (2020) Diagrammatic Monte Carlo study of the Holstein polaron. [Laurea magistrale], Università di Bologna, Corso di Studio in Physics [LM-DM270]
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The aim of the thesis is to apply the Diagrammatic Monte Carlo numerical method [N. V. Prokof’ev and B. V. Svistunov, Phys. Rev. Lett. 81, 2514, 1998] to the Holstein model of the lattice polaron. As part of this work, the method was implemented in a computer program, and its results were collected and analyzed. The study focuses on ground state properties of the Holstein polaron, such as energy, effective mass and average number of phonons. Observables are computed via an improved approach using estimators developed by Mishchenko [A. Mishchenko et al., Phys. Rev. B, vol. 62, 09, 2009]. The dependency of polaron properties on coupling and momentum is investigated for different dimensionalities (1D, 2D and 3D). Results are compared to analytical expressions obtained in the weak-coupling and strong-coupling limits and to other approaches found in literature.

Tipologia del documento
Tesi di laurea (Laurea magistrale)
Autore della tesi
Ragni, Stefano
Relatore della tesi
Correlatore della tesi
Corso di studio
Ordinamento Cds
Parole chiave
dmc,dqmc,diagrammatic monte carlo,holstein,polaron,quantum monte carlo,markov chain,monte carlo,lattice polaron,small polaron
Data di discussione della Tesi
11 Dicembre 2020

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