Scior, Philipp (2016)
Lattice Simulations of QCD-like Theories at Finite Baryon Density.
Technische Universität Darmstadt
Dissertation, Erstveröffentlichung
Kurzbeschreibung (Abstract)
The exploration of the phase diagram of quantum chromodynamics (QCD) is of great importance to describe e.g. the properties of neutron stars or heavy-ion collisions. Due to the sign problem of lattice QCD at finite chemical potential we need effective theories to study QCD at finite density. Here, we will use a three-dimensional Polyakov-loop theory to study the phase diagrams of QCD-like theories. In particular, we investigate the heavy quark limit of the QCD-like theories where the effective theory can be derived from the full theory by a combined strong coupling and hopping expansion. This expansion can be systematically improved order by order. Since there is no sign problem for the QCD-like theories we consider, we can compare our results to data from lattice calculations of the full theories to make qualitative and quantitative statements of the effective theory’s validity. We start by deriving the effective theory up to next-to-next-to leading-oder, in particular for two-color and G2-QCD where replace the three colors in QCD with only two colors or respectively replace the gauge group SU(3) of QCD with G2. We will then apply the effective theory at finite temperature mainly to test the theory and the implementation but also to make some predictions for the deconfinement phase transition in G2 Yang-Mills theory. Finally, we will turn our attention to the cold and dense regime of the phase diagram where we observe a sharp increase of the baryon density with the quark chemical potential μ, when μ reaches half the diquark mass. At vanishing temperature this is expected to happen in a quantum phase transition with Bose-Einstein-condensation of diquarks. In contrast to the liquid-gas transition in QCD, the phase transition to the Bose-Einstein condensate is continuous. We find evidence that the effective theories for heavy quarks are able to describe the qualitative difference between first and second order phase transitions. For even higher μ we find the rise of the Polyakov loop as well as the quark number density up to the characteristic saturation of the respective theory on a finite lattice.
| Typ des Eintrags: | Dissertation | ||||
|---|---|---|---|---|---|
| Erschienen: | 2016 | ||||
| Autor(en): | Scior, Philipp | ||||
| Art des Eintrags: | Erstveröffentlichung | ||||
| Titel: | Lattice Simulations of QCD-like Theories at Finite Baryon Density | ||||
| Sprache: | Englisch | ||||
| Referenten: | von Smekal, Prof. Dr. Lorenz ; Wambach, Prof. Dr. Jochen | ||||
| Publikationsjahr: | 2016 | ||||
| Ort: | Darmstadt | ||||
| Datum der mündlichen Prüfung: | 13 Juli 2016 | ||||
| URL / URN: | http://tuprints.ulb.tu-darmstadt.de/5625 | ||||
| Kurzbeschreibung (Abstract): | The exploration of the phase diagram of quantum chromodynamics (QCD) is of great importance to describe e.g. the properties of neutron stars or heavy-ion collisions. Due to the sign problem of lattice QCD at finite chemical potential we need effective theories to study QCD at finite density. Here, we will use a three-dimensional Polyakov-loop theory to study the phase diagrams of QCD-like theories. In particular, we investigate the heavy quark limit of the QCD-like theories where the effective theory can be derived from the full theory by a combined strong coupling and hopping expansion. This expansion can be systematically improved order by order. Since there is no sign problem for the QCD-like theories we consider, we can compare our results to data from lattice calculations of the full theories to make qualitative and quantitative statements of the effective theory’s validity. We start by deriving the effective theory up to next-to-next-to leading-oder, in particular for two-color and G2-QCD where replace the three colors in QCD with only two colors or respectively replace the gauge group SU(3) of QCD with G2. We will then apply the effective theory at finite temperature mainly to test the theory and the implementation but also to make some predictions for the deconfinement phase transition in G2 Yang-Mills theory. Finally, we will turn our attention to the cold and dense regime of the phase diagram where we observe a sharp increase of the baryon density with the quark chemical potential μ, when μ reaches half the diquark mass. At vanishing temperature this is expected to happen in a quantum phase transition with Bose-Einstein-condensation of diquarks. In contrast to the liquid-gas transition in QCD, the phase transition to the Bose-Einstein condensate is continuous. We find evidence that the effective theories for heavy quarks are able to describe the qualitative difference between first and second order phase transitions. For even higher μ we find the rise of the Polyakov loop as well as the quark number density up to the characteristic saturation of the respective theory on a finite lattice. |
||||
| Alternatives oder übersetztes Abstract: |
|
||||
| URN: | urn:nbn:de:tuda-tuprints-56253 | ||||
| Sachgruppe der Dewey Dezimalklassifikatin (DDC): | 500 Naturwissenschaften und Mathematik > 530 Physik | ||||
| Fachbereich(e)/-gebiet(e): | 05 Fachbereich Physik > Institut für Kernphysik > Theoretische Kernphysik > Quanten-Chromo-Dynamic 05 Fachbereich Physik > Institut für Kernphysik > Theoretische Kernphysik 05 Fachbereich Physik > Institut für Kernphysik 05 Fachbereich Physik |
||||
| Hinterlegungsdatum: | 14 Aug 2016 19:55 | ||||
| Letzte Änderung: | 14 Aug 2016 19:55 | ||||
| PPN: | |||||
| Referenten: | von Smekal, Prof. Dr. Lorenz ; Wambach, Prof. Dr. Jochen | ||||
| Datum der mündlichen Prüfung / Verteidigung / mdl. Prüfung: | 13 Juli 2016 | ||||
| Export: | |||||
| Suche nach Titel in: | TUfind oder in Google | ||||
 |
Frage zum Eintrag |
Optionen (nur für Redakteure)
 |
Redaktionelle Details anzeigen |
Drucken
Impressum