714 research outputs found
Classical and Quantum Behavior in Mean-Field Glassy Systems
In this talk I review some recent developments which shed light on the main
connections between structural glasses and mean-field spin glass models with a
discontinuous transition. I also discuss the role of quantum fluctuations on
the dynamical instability found in mean-field spin glasses with a discontinuous
transition. In mean-field models with pairwise interactions in a transverse
field it is shown, in the framework of the static approximation, that such
instability is suppressed at zero temperature.Comment: 9 Pages (including 5 Figures), Revtex, Proceedings of the XIV Sitges
Conference, June 1996 (Barcelona) Spai
Solving a Coupled Set of Truncated QCD Dyson-Schwinger Equations
Truncated Dyson-Schwinger equations represent finite subsets of the equations
of motion for Green's functions. Solutions to these non-linear integral
equations can account for non-perturbative correlations. A closed set of
coupled Dyson-Schwinger equations for the propagators of gluons and ghosts in
Landau gauge QCD is obtained by neglecting all contributions from irreducible
4-point correlations and by implementing the Slavnov-Taylor identities for the
3-point vertex functions. We solve this coupled set in an one-dimensional
approximation which allows for an analytic infrared expansion necessary to
obtain numerically stable results. This technique, which was also used in our
previous solution of the gluon Dyson-Schwinger equation in the Mandelstam
approximation, is here extended to solve the coupled set of integral equations
for the propagators of gluons and ghosts simultaneously. In particular, the
gluon propagator is shown to vanish for small spacelike momenta whereas the
previoulsy neglected ghost propagator is found to be enhanced in the infrared.
The running coupling of the non-perturbative subtraction scheme approaches an
infrared stable fixed point at a critical value of the coupling, alpha_c
approximately 9.5.Comment: 23 pages, 6 figures, LaTeX2
The Case against Copyright: A Comparative Institutional Analysis of Intellectual Property Regimes
The President's Constitutional Authority to Conduct Military Operations Against Terrorist Organizations and the Nations that Harbor or Support Them
Relativistic Nucleus-Nucleus Collisions and the QCD Matter Phase Diagram
This review will be concerned with our knowledge of extended matter under the
governance of strong interaction, in short: QCD matter. Strictly speaking, the
hadrons are representing the first layer of extended QCD architecture. In fact
we encounter the characteristic phenomena of confinement as distances grow to
the scale of 1 fm (i.e. hadron size): loss of the chiral symmetry property of
the elementary QCD Lagrangian via non-perturbative generation of "massive"
quark and gluon condensates, that replace the bare QCD vacuum. However, given
such first experiences of transition from short range perturbative QCD
phenomena (jet physics etc.), toward extended, non perturbative QCD hadron
structure, we shall proceed here to systems with dimensions far exceeding the
force range: matter in the interior of heavy nuclei, or in neutron stars, and
primordial matter in the cosmological era from electro-weak decoupling (10^-12
s) to hadron formation (0.5 10^-5 s). This primordial matter, prior to
hadronization, should be deconfined in its QCD sector, forming a plasma (i.e.
color conducting) state of quarks and gluons: the Quark Gluon Plasma (QGP).Comment: 146 pages, 83 figure
- …