Mass Spectrum of the 3d SU(2) Higgs Model and the Symmetric Electroweak Phase

We present results for the masses of the low-lying states with quantum numbers $0^{++}$, $2^{++}$ and $1^{--}$ as well as Polyakov line correlations in the Higgs and confinement regions of the 3d SU(2) Higgs model. In the confinement phase we find a dense spectrum of bound states approximately split into two disjoint sectors. One consists of W-balls nearly identical to the glueball spectrum of the pure gauge theory, the other of bound states of scalars.Comment: Talk presented at LATTICE96(electroweak), 3 pages, 3 figures using epsf.st

On the neutrality issue in the Polyakov-loop NJL model

We elucidate how the color neutrality is harmed in the Polyakov Nambu-Jona Lasinio (PNJL) model at finite density within the adopted mean field approximation. Also we point out how usual assumption about the diagonal form of the Wilson loop may fail in the presence of the diquark condensate on several grounds.Comment: 8 pages, 1 figure. Introduction enlarged, several comments about the adopted mean field approximation and the relation with Elitzur's theorem added. Version to appear on Phys. Rev.

Chiral crossover, deconfinement and quarkyonic matter within a Nambu-Jona Lasinio model with the Polyakov loop

We study the interplay between the chiral and the deconfinement transitions, both at high temperature and high quark chemical potential, by a non local Nambu-Jona Lasinio model with the Polyakov loop in the mean field approximation and requiring neutrality of the ground state. We consider three forms of the effective potential of the Polyakov loop: two of them with a fixed deconfinement scale, cases I and II, and the third one with a $\mu$ dependent scale, case III. In the cases I and II, at high chemical potential $\mu$ and low temperature $T$ the main contribution to the free energy is due to the Z(3)-neutral three-quark states, mimicking the quarkyonic phase of the large $N_c$ phase diagram. On the other hand in the case III the quarkyonic window is shrunk to a small region. Finally we comment on the relations of these results to lattice studies and on possible common prospects. We also briefly comment on the coexistence of quarkyonic and color superconductive phases.Comment: 16 pages, 7 figures, RevTeX4. Some typos corrected, references adde

Scalar-gauge dynamics in (2+1) dimensions at small and large scalar couplings

We present the results of a detailed calculation of the excitation spectrum of states with quantum numbers J^{PC}=0++, 1-- and 2++ in the three-dimensional SU(2) Higgs model at two values of the scalar self-coupling and for fixed gauge coupling. In the context of studies of the electroweak phase transition at finite temperature these couplings correpond to tree-level, zero temperature Higgs masses of 35 GeV and 120 GeV, respectively. We also study the properties of Polyakov loop operators, which serve to test the confining properties of the model in the symmetric phase. At both values of the scalar coupling we obtain masses of bound states consisting entirely of gauge degrees of freedom ("W-balls"), which are very close to those obtained in the pure gauge theory. We conclude that the previously observed, approximate decoupling of the scalar and gauge sectors of the theory persists at large scalar couplings. We study the crossover region at large scalar coupling and present a scenario how the confining properties of the model in the symmetric phase are lost inside the crossover by means of flux tube decay. We conclude that the underlying dynamics responsible for the observed dense spectrum of states in the Higgs region at large couplings must be different from that in the symmetric phase.Comment: 36 pages, LaTeX, 13 postscript files, to be included with epsf; improved presentation, updated references, conclusions unchanged; version to appear in Nucl. Phys.

A Method Off the Beaten Track: Refining Creative Writing Process through Practice-led Research

How can you improve your writing processes and your creative projects by examining your own working conditions? In this article, we address this question and the possibilities and challenges of the method called ‘practice-led research’, which is a method off the beaten track in media production studies. We examine assignments by students from the educational program of ‘Screenplay Development’ at the University of Southern Den-mark. Our purpose is to clarify how the students have used practice-led research to enhance their screenwriting, and whether this method has contributed to their talent development. The theoretical framework in the article is constituted by Donald Schön’s (2013) practice epistemology. As our analytical lens we use Robin Nelson’s (2013) modes of thinking, as well as talent development theories by Anders Ericsson (Ericsson & Pool, 2016) and Mihalyi Csikszentmihalyi (1996). Based on our findings, we suggest how to get started you’re your creative writing and improve your writing processes

String breaking with dynamical Wilson fermions

We present results of our ongoing determination of string breaking in full QCD with N_f=2 Wilson fermions. Our investigation of the fission of the static quark-antiquark string into a static-light meson-antimeson system is based on dynamical configurations of size 24^3 x 40 produced by the TxL collaboration. Combining various optimization methods we determine the matrix elements of the two-by-two system with so far unprecedented accuracy. The all-to-all light quark propagators occurring in the transition element are computed from eigenmodes of the Hermitian Wilson-Dirac matrix complemented by stochastic estimates in the orthogonal subspace. We observe a clear signature for level-splitting between ground state and excited potential. Thus, for the first time, string breaking induced by sea quarks is observed in a simulation of 4-dimensional lattice-QCD.Comment: 3 pages, 3 figures, contribution to Lattice 200

Heavy Quark Interactions and Quarkonium Binding

We consider heavy quark interactions in quenched and unquenched lattice QCD. In a region just above the deconfinement point, non-Abelian gluon polarization leads to a strong increase in the binding. Comparing quark-antiquark and quark-quark interaction, the dependence of the binding on the separation distance $r$ is found to be the same for the colorless singlet $Q\bar Q$ and the colored anti-triplet $QQ$ state. In a potential model description of in-medium $J/\Psi$ behavior, this enhancement of the binding leads to a survival up to temperatures of 1.5 $T_c$ or higher; it could also result in $J/\Psi$ flow.Comment: 8 pages, 8 Figures; invited talk at "Strangeness in Quark Matter 2008", Beijing/China, to appear in the Proceeding

String Breaking and Quarkonium Dissociation at Finite Temperatures

Recent lattice studies of string breaking in QCD with dynamical quarks determine the in-medium temperature dependence of the heavy quark potential. Comparing this to the binding energies of different quarkonium states, we check if these can decay into open charm/beauty in a confined hadronic medium. Our studies indicate in particular that the chi_c and the psi dissociate into open charm below the deconfinement point.Comment: 8 pages LaTeX, 4 figure

Reaction behavior of iron and copper complexes towards dioxygen

To provide a better understanding of the reactions of iron and copper proteins with dioxygen, the corresponding reactions of small molecule model complexes with dioxygen were analysed using spectroscopic and kinetic methods. Special attention focused upon the binding and activation of dioxygen by iron proteins such as hemerythrin (Hr) and protocatechuat-3,4-dioxygenase (3,4-PCD) and by copper proteins like hemocyanin (Hc) and tyrosinase. Iron complexes of the ligand tmpa (tmpa = tris[(2-pyridyl)methyl]amine, also known as tpa in literature) were synthesised and modifications of the tmpa ligand were made. Increasing as well as decreasing chelate ring sizes in the highly active complex [Fe(tmpa)(dbc)]B(C6H5)4 (dbc = 3,5-di-tert-butylcatecholate dianion), only resulted in decreased reactivity of the investigated compounds. A detailed low-temperature stopped-flow investigation of the reaction of dioxygen with [Fe(tmpa)(dbc)]B(C6H5)4 was performed and activation parameters of Delta H# = 23 +- 1 kJ mol-1 and Delta S# = -199 +- 4 J mol-1 K-1 were obtained. Crystal structures of bromo-(tetrachlorocatecholato-O,O\u27)(bis((2-pyridyl)methyl)-2-pyridylamine-N,N\u27,N\u27\u27)-iron(III) (2), (mu-oxo)-bis(bromo)(bis((2-pyridyl)methyl)-2-pyridylamine-N,N\u27,N\u27\u27,N\u27\u27\u27)-diiron(III) (3), dichloro-((2-(2-pyridyl)ethyl)bis((2-pyridyl)methyl)amine-N,N\u27,N\u27\u27,N\u27\u27\u27)-iron(III) (4) and (tetrabromocatecholato-O,O\u27)((2-(2-pyridyl)ethyl)bis((2-pyridyl)methyl)amine-N,N\u27,N\u27\u27,N\u27\u27\u27)-iron(III) (5) are reported (Chapter 2). Besides altering the chelate ring size the influence of the donor atoms of the ligand on catechol dioxygenase reactivity was investigated. Two derivatives of the tmpa ligand (uns-penp and acetyl-uns-penp) were synthesised, where one aromatic nitrogen donor was replaced by an aliphatic nitrogen donor. The iron(III) complexes of the tripodal ligands N\u27,N\u27-bis[(2-pyridyl)methyl]ethylenediamine (uns-penp), [Fe(uns-penp)Cl2]ClO4 x CH3CN, [{Fe(uns-penp)Cl}2O](ClO4)2 x 2CH3CN and the amide derivative N-Acetyl-N\u27,N\u27-bis[(2-pyridyl)methyl]ethylenediamine (acetyl-uns-penp), [Fe2(acetyl-uns-penp)2O](ClO4)2 x H2O, [Fe(acetyl-uns-penp)(tcc)Br] x (C2H5)2O and [{Fe(acetyl-uns-penp)(tcc)}2O] x (C2H5)2O x CH3OH were synthesised and characterised. Catechol dioxygenase reactivity of in situ prepared complex solutions only showed slower reactions in comparison with the iron tmpa system (Chapter 3). Corresponding ligand system variations in the small molecule model complexes of copper proteins were made and analysed with respect to dioxygen reactivity. Intramolecular ligand hydroxylation was observed during the reactions of dioxygen with the dicopper(I) complexes of the ligands L3 (L3 = alpha,alpha\u27-bis[(2-pyridylethyl)amino]-m-xylene) and L5 (L5 = alpha,alpha\u27-bis[N-(2-pyridylethyl)-N-(2-pyridylmethyl)-amino]-m-xylene). The dinuclear copper(I) complex [Cu2L5](ClO4)2 and the dicopper(II) complex [Cu2(L3-O)(OH)(ClO4)]ClO4 were characterised by single-crystal X-ray structure analysis. Furthermore, phenolate-bridged complexes were synthesised with the ligand L4-OH and Me-L5-OH (structurally characterised: [Cu2(L4-O)Cl3] with L4 = alpha,alpha\u27-bis[N-methyl-N-(2-pyridylethyl)amino]-m-xylene and [Cu2(Me-L5-O)(mu-X)](ClO4)2 x nH2O with Me-L5-OH = 2,6-bis[N-(2-pyridylethyl)-N-(2-pyridylmethyl)amino]-4-methylphenol and X = C3H3N2- (prz), MeCO2- and N3-). Temperature-dependent magnetic studies revealed the antiferromagnetic coupling of the copper ions of these complexes (Chapter 4). The reactions of dioxygen with copper(I) complexes of the tridentate ligands 1,1,4,7,7-pentamethyldiethylethylenetriamine (Me5dien), 1,1,4,7,7-pentaethyldiethylethylenetriamine (Et5dien), N-methyl-[bis(2-pyridyl)methyl]amine (Me-bpa) and N-methyl-[(2-pyridyl)ethyl(2-pyridyl)methyl]amine (MeL) have been investigated using low-temperature stopped-flow techniques. The formation of a bis(mu-oxo) copper complex as a reactive intermediate could only be detected spectroscopically at low temperatures for [Cu(Me5dien)(CH3CN)]ClO4 and allowed a quantitative kinetic analysis to be performed. Crystal structures of the copper(II) complexes [(Me-bpa)Cu(Cl)2], [{(Me-bpa)Cu(Cl)(ClO4)}2], [{(MeL)Cu(Cl)(ClO4)}2] and [(MeL)Cu(NCS)2] are reported. (Chapter 5)Zum besseren Verständnis der Reaktionen von Eisen- und Kupferproteinen mit elementarem Sauerstoff wurden im Rahmen dieser Arbeit für Eisen- und Kupferproteine Modellkomplexe mit geringer Molekularmasse mit spektroskopischen oder kinetischen Methoden untersucht. Besondere Aufmerksamkeit wurde hierbei der Bindung und der Aktivierung von elementarem Sauerstoff durch die Eisenproteine, wie z. B. Hämerythrin (Hr) und Protocatechuat-3,4-dioxygenase (3,4-PCD), und die Kupferproteine, wie z. B. Hämocyanin (Hc) und Tyrosinase, gewidmet. Bezüglich der Modelle für Eisenenzyme wurde der Ligand tmpa (tmpa = tris[(2-pyridyl)methyl]amin; in der Literatur auch mit tpa abgekürzt) untersucht und systematisch variiert. Die Vergrößerung und Verkleinerung der Chelatringgröße im hochreaktiven Komplex [Fe(tmpa)(dbc)]B(C6H5)4 (dbc = 3,5-Di-tert-butylcatecholat Dianion) führte nur zu einer verringerten Reaktivität der untersuchten Verbindungen. Die Reaktion von elementaren Sauerstoff mit [Fe(tmpa)(dbc)]B(C6H5)4 wurde mittels der Tieftemperatur-\u27stopped-flow\u27-Technik untersucht und ergab die Aktivierungsparameter Delta H# = 23 +- 1 kJ mol-1 und Delta S# = -199 +- 4 J mol-1 K-1. Weiterhin wurden die Kristallstrukturanalysen der Verbindungen bromo-(tetra-chlorocatecholato-O,O\u27)(bis((2-pyridyl)methyl)-2-pyridylamine-N,N\u27,N\u27\u27)-eisen(III) (2), (mü-oxo)-bis(bromo)(bis((2-pyridyl)methyl)-2-pyridylamine-N,N\u27,N\u27\u27,N\u27\u27\u27)-dieisen (III) (3), dichloro-((2-(2-pyridyl)ethyl)bis((2-pyridyl)methyl)amine-N,N\u27,N\u27\u27,N\u27\u27\u27)-eisen (III) (4) und (tetrabromocatecholato-O,O\u27)((2-(2-pyridyl)ethyl)bis((2-pyridyl)methyl) amine-N,N\u27,N\u27\u27,N\u27\u27\u27)-eisen (III) (5) beschrieben (Kapitel 2). Neben der Änderung der Chelatringgröße wurde auch der Einfluss der Donoratome des Liganden untersucht. Dazu wurden abgeleitet vom tmpa zwei Liganden (uns-penp und acteyl-uns-penp) synthetisiert, bei denen ein aromatischer Stickstoff durch einen aliphatischen Stickstoff ersetzt wurde. Die Eisen(III)-Komplexe mit den tripodalen Liganden N\u27,N\u27-bis[(2-pyridyl)methyl]ethylenediamin (uns-penp), [Fe(uns-penp)Cl2]ClO4 x CH3CN, [{Fe(uns-penp)Cl}2O](ClO4)2 x 2CH3CN und dem Amidderivat N-Acetyl-N\u27,N\u27-bis[(2-pyridyl)methyl]ethylenediamin (acetyl-uns-penp), [Fe2(acetyl-uns-penp)2O](ClO4)2 x H2O, [Fe(acetyl-uns-penp)(tcc)Br] x (C2H5)2O und [{Fe(acetyl-uns-penp)(tcc)}2O] x (C2H5)2O x CH3OH wurden synthetisiert und charakterisiert. Untersuchungen zur Catecholdioxygenasereaktivität der in situ dargestellten Komplexlösungen zeigten nur langsamere Reaktionen im Vergleich zu dem Eisen-tmpa-System (Kapitel 3) Die Ligandensysteme für Modelle von Kupferproteinen wurden nach denselben Gesichtspunkten verändert wie bei den Modellen für die Eisenproteine. Intramolekulare Hydroxylierung des Liganden war bei der Reaktion von elementaren Sauerstoff mit Dikupfer(I)-Komplexen der Liganden L3 (L3 = alpha,alpha\u27-bis[(2-pyridylethyl)amino]-m-xylol) und L5 (L5 = alpha,alpha\u27-bis[N-(2-pyridylethyl)-N-(2-pyridylmethyl)-amino]-m-xylol) zu beobachten. Der dinukleare Kupfer(I)-Komplex [Cu2L5](ClO4)2 und der Dikupfer(II)-Komplex [Cu2(L3-O)(OH)(ClO4)]ClO4 konnten durch Einkristallröntgenstrukturanalyse charakterisiert werden. Zusätzlich wurden Phenolatverbrückte Komplexe mit den Liganden L4-OH und Me-L5-OH synthetisiert (Strukturlösungen für [Cu2(L4-O)Cl3] mit L4 = alpha,alpha\u27-bis[N-methyl-N-(2-pyridylethyl)amino]-m-xylol und [Cu2(Me-L5-O)(mü-X)](ClO4)2 x nH2O (Me-L5-OH = 2,6-bis[N-(2-pyridylethyl)-N-(2-pyridylmethyl)amino]-4-methylphenol und X = C3H3N2- (prz), MeCO2- und N3-). Temperaturabhängige magnetische Untersuchungen zeigten antiferromagnetische Kopplung der Kupferionen in diesen Komplexen (Kapitel 4). Die Reaktionen von elementaren Sauerstoff mit Kupfer(I)-Komplexen der dreizähnigen Liganden 1,1,4,7,7-pentamethyldiethylethylenetriamin (Me5dien), 1,1,4,7,7-pentaethyldiethylethylenetriamin (Et5dien), N-methyl-[bis(2-pyridyl) methyl]amin (Me-bpa) und N-methyl-[(2-pyridyl)ethyl(2-pyridyl)methyl]amin (MeL) mit Hilfe der Tieftemperatur-\u27stopped-flow\u27-Technik untersucht. Die Bildung eines bis(mü-oxo)-Kupferkomplexes konnte dabei bei tiefen Temperaturen nur für den Komplex [Cu(Me5dien)(CH3CN)]ClO4 spektroskopisch beobachtet und quantitativ kinetisch analysiert werden. Die Komplexe [(Me-bpa)Cu(Cl)2], [{(Me-bpa)Cu(Cl)(ClO4)}2], [{(MeL)Cu(Cl)(ClO4)}2] und [(MeL)Cu(NCS)2] konnten kristallographisch charakterisiert werden. (Kapitel 5