QCD at finite density with Dyson-Schwinger equations
In this work we investigate QCD at finite density with Dyson-Schwinger equations. In the first part we consider color-superconducting phases, which occur at high densities through the formation of quark-quark pairs. We describe 2SC and CFL phases with massive strange quarks. We calculate the phase d...
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| Format: | Others |
| Language: | German en |
| Published: |
2013
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| Online Access: | http://tuprints.ulb.tu-darmstadt.de/3483/1/main.pdf Müller, Daniel <http://tuprints.ulb.tu-darmstadt.de/view/person/M=FCller=3ADaniel=3A=3A.html> : QCD at finite density with Dyson-Schwinger equations. Technische Universität, Darmstadt [Ph.D. Thesis], (2013) |
| Summary: | In this work we investigate QCD at finite density with Dyson-Schwinger equations. In the first part we consider color-superconducting phases, which occur at high densities through the formation of quark-quark pairs. We describe 2SC and CFL phases with massive strange quarks. We calculate the phase diagram in a hard-thermal-loop / hard-dense-loop approximation which describes the back-coupling of massless quarks to the gluons. We fixed the vertex parameters to a chiral critical temperature of Tc=150 MeV. This approximation results in low critical temperatures for the color-superconducting phases around 20-30 MeV and a too large pion decay constant. To improve the truncation we couple the full color-superconducting quark propagator back to the gluons. In addition to more realistic vacuum observables also the critical temperatures increase to 40-60 MeV. We find a dominant CFL phase at high densities, while at intermediate chemical potential, the ground state is a 2SC phase which also extents to a small band between CFL and normal conducting phase. We also calculate Debye and Meissner masses of the gluons, which can reproduce the results of weak-coupling calculations.
In the second part of this work we consider chiral condensates with the possibility of spatial modulations. We investigate 1-dimensional modulations with plane-wave shape, which oscillate between a scalar and a pseudoscalar condensate, in the Dyson-Schwinger formalism. We find an inhomogeneous phase that covers the original first-order chiral phase transition, which is in agreement with similar model calculations. |
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