Blar i NTNU Open på forfatter "Andersen, Jens Oluf"
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Quark and Hybrid Stars with the Quark-Meson Model — Including Preliminaries to Compact Stars
Sletmoen, Herman (Master thesis, 2022)Ifølge kvantekromodynamikk bryter innesperrede kvarker fri fra hadroner til en tilstand av uavgrenset kvarkmaterie ved høy tetthet. Nylige observasjoner av de massive 2 M_☉-pulsarene PSR J1614-2230, PSR J0348+0432 og PSR ... -
Quark and pion condensates at finite isospin density in chiral perturbation theory
Adhikari, Prabal; Andersen, Jens Oluf (Peer reviewed; Journal article, 2020)I denne artikkelen vurderer vi to-smak QCD ved null temperatur og endelig isospin kjemisk potensiale μJegμI ved hjelp av en modelluavhengig analyse innen chiral forstyrrelsesteori i neste ledende rekkefølge. Vi beregner ... -
Quark, Hybrid, and Unified Hybrid Stars with the Quark-Meson Model
Andresen, Carl Fredrik (Master thesis, 2023)Vi beskriver kalde, sfærisk-symmetriske, kompakte stjerner med kvark-meson-modellen med to kvarker. Til å begynne med utleder vi relevante termodynamiske størrelser fra kvantefeltteori ved endelig kjemisk potensial. Vi ... -
The Quark-meson model in a magnetic field
Grøver, Sigurd Loe (Master thesis, 2017)In this thesis we study the chiral phase transition of two-flavor QCD, through the use of the quark-meson model. The effect of a magnetic field on the transition is studied, at finite temperature and baryon chemical ... -
Stochastic inflation from quantum field theory and the parametric dependence of the effective noise amplitude
Andersen, Jens Oluf; Tranberg, Anders; Eriksson, Magdalena Britt (Journal article; Peer reviewed, 2022) -
Svakt vekselvirkende Bosegasser ved lave temperaturer: Et studium av Bose-Einstein kondensasjon ved bruk av effektiv feltteori.
Ingvaldsen, Morten (Master thesis, 2009)I denne masteroppgaven tar vi for oss svakt vekselvirkende Bosegasser, og vi skal se at et slik system har en annen oppførsel enn en ideell gass selv ved temperatur T=0. I tillegg skal vi finne en effektiv feltteori for ... -
The Chiral Phase Transition in QCD: Mean-Field Versus the Functional Renormalisation Group
Glesaaen, Jonas Rylund (Master thesis, 2013)In this thesis we map out the phase diagram of the chiral phase transition of quantum chromodynamics (QCD) in the plane of temperature and quark chemical potential. We use the linear sigma model with quarks (LSMq) as a low ... -
The chiral transition in a magnetic background: Finite density effects and the functional renormalization group
Andersen, Jens Oluf; Tranberg, Anders (Journal article; Peer reviewed, 2012)We compute the phase diagram of the quark-meson model at finite temperature, finite baryon chemical potential μ B = 3 μ and constant external magnetic field B, using the functional renormalization group. Our results show ... -
The Structure of Quark Stars
Berge, Eirik Samuel (Master thesis, 2013)In this thesis we will study the structure of quark stars using different models to mimic the interactions of quantum chromodynamics (QCD).The models we encounter is the MIT bag model and the two-and three-flavour linear ... -
The Vacuum Polarisation Contribution to the Lamb Shift Using Non-Relativistic Quantum Electrodynamics
Frafjord, Jonas (Master thesis, 2016)In this thesis we calculate the vacuum polarisation contribution to the well-known Lamb shift. The Lamb shift is a correction of order $\alpha^5$ to the non-relativistic energy spectrum of the hydrogen atom. We discuss the ... -
Thermodynamics and phase diagrams of Polyakov-loop extended chiral models
Folkestad, Åsmund; Andersen, Jens Oluf (Journal article; Peer reviewed, 2019)We study the thermodynamics and phase diagrams of two-flavor quantum chromodynamics using the Polyakov-loop extended quark-meson (PQM) model and the Pisarski-Skokov chiral matrix (χM) model [1]. At temperatures up to T≈2Tc ... -
Thermodynamics of the nonlinear sigma model
Livermore, Erik (Master thesis, 2020)I denne oppgava studerer vi termodynamikken til den ikke-lineære sigmamodellen i to dimensjoner, en leketøysmodell for den sterke vekselvirkningen. Vi presenterer grunnleggende termisk kvantefeltteori og utleder modellen ... -
Three-loop HTL QCD thermodynamics
Andersen, Jens Oluf; Leganger, Lars Erlend; Strickland, Michael; Su, Nan (Journal article; Peer reviewed, 2011)The hard-thermal-loop perturbation theory (HTLpt) framework is used to calculate the thermodynamic functions of a quark-gluon plasma to three-loop order. This is the highest order accessible by finite temperature perturbation ... -
Three-loop HTLpt thermodynamics at finite temperature and chemical potential
Haque, Najmul; Bandyopadhyay, Aritra; Andersen, Jens Oluf; Mustafa, Munshi; Strickland, Michael; Su, Nan (Journal article; Peer reviewed, 2014)We calculate the three-loop thermodynamic potential of QCD at finite temperature and chemical potential(s) using the hard-thermal-loop perturbation theory (HTLpt) reorganization of finite temperature and density QCD. The ... -
Two-flavor chiral perturbation theory at finite isospin density beyond leading order
Mojahed, Martin Aria (Master thesis, 2020)I denne avhandlinga studerer me two-flavor QCD ved endeleg isospin kjemisk potensial ved å bruke kiral perturbasjonsteori forbi leiande orden i lågenergi ekspansjonen. Me reknar ut pionkondensatet og det kirale kondensatet ... -
Two-flavor chiral perturbation theory at nonzero isospin: Pion condensation at zero temperature
Adhikari, Prabal; Andersen, Jens Oluf; Kneschke, Patrick (Journal article; Peer reviewed, 2019)In this paper, we calculate the equation of state of two-flavor finite isospin chiral perturbation theory at next-to-leading order in the pion-condensed phase at zero temperature. We show that the transition from the vacuum ...