Berndt Müller

The Casimir Effect

Abstract This report gives an introduction to the Casimir effect in quantum field theory and its applications. The interaction between the vacuum of a quantized field and an external boundary or a classical external field is investigated laying particular emphasis on Casimirs concept of measurable change in the vacuum energy. The various methods for evaluation and regularization of the Casimir energy are discussed in detail for specific field configurations. Recent applications of the Casimir effect in supercritical fields, QCD bag models and electromagnetic media are reviewed.

Hadronization in heavy ion collisions: Recombination and fragmentation of partons

We argue that the emission of hadrons with transverse momentum up to about 5 GeV/c in central relativistic heavy ion collisions is dominated by recombination, rather than fragmentation of partons. This mechanism provides a natural explanation for the observed constant baryon-to-meson ratio of about one and the apparent lack of a nuclear suppression of the baryon yield in this momentum range. Fragmentation becomes dominant at higher transverse momentum, but the transition point is delayed by the energy loss of fast partons in dense matter.

Thermalization of Strongly Coupled Field Theories

Using the holographic mapping to a gravity dual, we calculate 2-point functions, Wilson loops, and entanglement entropy in strongly coupled field theories in d=2, 3, and 4 to probe the scale dependence of thermalization following a sudden injection of energy. For homogeneous initial conditions, the entanglement entropy thermalizes slowest and sets a time scale for equilibration that saturates a causality bound. The growth rate of entanglement entropy density is nearly volume-independent for small volumes but slows for larger volumes. In this setting, the UV thermalizes first.

Hadron production in heavy ion collisions: Fragmentation and recombination from a dense parton phase

We discuss hadron production in heavy ion collisions at the Relativistic Heavy Ion Collider (RHIC). We argue that hadrons at transverse momenta

First Results from Pb+Pb collisions at the LHC

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Dynamics of parton cascades in highly relativistic nuclear collisions

are formed by recombination of partons from the dense parton phase created in central collisions at RHIC. We provide a theoretical description of the recombination process for

THE SEARCH FOR THE QUARK-GLUON PLASMA

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Extracting the jet transport coefficient from jet quenching in high-energy heavy-ion collisions

. Below

Results from the Relativistic Heavy Ion Collider

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High-energy photons from passage of jets through Quark-Gluon plasma.

our results smoothly match a purely statistical description. At high transverse momentum hadron production is well described in the language of perturbative QCD by the fragmentation of partons. We give numerical results for a variety of hadron spectra, ratios, and nuclear suppression factors. We also discuss the anisotropic flow