1,910 research outputs found
Uniqueness of infrared asymptotics in Landau gauge Yang-Mills theory
We uniquely determine the infrared asymptotics of Green functions in Landau
gauge Yang-Mills theory. They have to satisfy both,
Dyson-Schwinger equations and functional renormalisation group equations.
Then, consistency fixes the relation between the infrared power laws of these
Green functions. We discuss consequences for the interpretation of recent
results from lattice QCD.Comment: 24 pages, 8 figure
Uniqueness of infrared asymptotics in Landau gauge Yang-Mills theory II
We present a shortened and simplified version of our proof
\cite{Fischer:2006vf} of the uniqueness of the scaling solution for the
infrared asymptotics of Green functions in Landau gauge Yang-Mills theory. The
simplification relates to a new RG-invariant arrangement of Green functions
applicable to general theories. As before the proof relies on the necessary
consistency between Dyson-Schwinger equations (DSEs) and functional
renormalisation group equations (FRGs). We also demonstrate the existence of a
specific scaling solution for both, DSEs and FRGs, that displays uniform and
soft kinematic singularities.Comment: 12 pages, 10 figure
Polyakov loop potential at finite density
The Polyakov loop potential serves to distinguish between the confined
hadronic and the deconfined quark-gluon plasma phases of QCD. For Nf=2+1 quark
flavors with physical masses we determine the Polyakov loop potential at finite
temperature and density and extract the location of the deconfinement
transition. We find a cross-over at small values of the chemical potential
running into a critical end-point at mu/T > 1.Comment: 5 pages, 9 figure
Critical Point and Deconfinement from Dyson-Schwinger Equations
We employ the Dyson-Schwinger equations for quark and gluon propagators in
order to study QCD with 2+1 flavours at finite temperature and density. In a
suitable truncation for these equations, we determine the position of the
critical end-point as well as the deconfinement temperature at all chemical
potentials. For the latter, the Polyakov-loop potential is obtained from the
QCD propagators. This is possible for the first time at finite chemical
potential, with implications for effective models.Comment: Proceedings for the 8th International Workshop on Critical Point and
Onset of Deconfinement (CPOD 2013). 5 pages, 5 figure
Signatures of confinement in Landau gauge QCD
We summarise an analysis of the infrared regime of Landau gauge QCD by means
of a flow equation approach. The infrared behaviour of gluon and ghost
propagators is evaluated. The results provide further evidence for the
Kugo-Ojima confinement scenario. We also discuss their relation to results
obtained with other functional methods as well as the lattice.Comment: 3 pages, talk given by JMP at 6th Conference on Quark Confinement and
the Hadron Spectrum, Villasimius, Sardinia, Italy, 21-25 Sep 200
QCD critical region and higher moments for three flavor models
One of the distinctive feature of the QCD phase diagram is the possible
emergence of a critical endpoint. The critical region around the critical point
and the path dependency of the critical exponents is investigated within
effective chiral (2+1)-flavor models with and without Polyakov-loops. Results
obtained in no-sea mean-field approximations where a divergent vacuum part in
the fermion-loop contribution is neglected, are confronted to the renormalized
ones. Furthermore, the modifications caused by the back-reaction of the matter
fluctuations on the pure Yang-Mills system are discussed. Higher order,
non-Gaussian moments of event-by-event distributions of various particle
multiplicities are enhanced near the critical point and could serve as a probe
to determine its location in the phase diagram. By means of a novel derivative
technique higher order generalized quark-number susceptibilities are calculated
and their sign structure in the phase diagram is analyzed.Comment: 12 pages, 11 figures. Final PRD version (references and one more
equation added
Extremal Isolated Horizons: A Local Uniqueness Theorem
We derive all the axi-symmetric, vacuum and electrovac extremal isolated
horizons. It turns out that for every horizon in this class, the induced metric
tensor, the rotation 1-form potential and the pullback of the electromagnetic
field necessarily coincide with those induced by the monopolar, extremal
Kerr-Newman solution on the event horizon. We also discuss the general case of
a symmetric, extremal isolated horizon. In particular, we analyze the case of a
two-dimensional symmetry group generated by two null vector fields. Its
relevance to the classification of all the symmetric isolated horizons,
including the non-extremal once, is explained.Comment: 22 pages, page size changed, typos and equations (142), (143a)
corrected, PACS number adde
Sensitivity analysis of the probabilistic damage stability regulations for RoPax vessels
In the light of the newly developed harmonised probabilistic damage stability regulations, set to come into force in 2009, this article presents a systematic and thorough analysis of the sensitivity of the Attained Subdivision Index with reference to a wide range of related design parameters. The sensitivity of the probabilistic regulations was investigated for a typical large RoPax vessel, with variation of parameters, such as the number, positioning and local optimisation of transverse bulkheads; the presence and position of longitudinal bulkheads below the main vehicle deck; the presence of side casings; and the height of the main deck and double bottom. The effects of water on deck and of operational parameters (draught, centre of gravity and trim) were also investigated. The results of the study, presented in graphical form, can provide valuable assistance to the designer when determining subdivision characteristics at the very early stage of the design process, resulting in optimal, efficient and safe ships
- …