186 research outputs found
Extensions and further applications of the nonlocal Polyakov--Nambu--Jona-Lasinio model
The nonlocal Polyakov-loop-extended Nambu--Jona-Lasinio (PNJL) model is
further improved by including momentum-dependent wave-function renormalization
in the quark quasiparticle propagator. Both two- and three-flavor versions of
this improved PNJL model are discussed, the latter with inclusion of the
(nonlocal) 't Hooft-Kobayashi-Maskawa determinant interaction in order to
account for the axial U(1) anomaly. Thermodynamics and phases are investigated
and compared with recent lattice-QCD results.Comment: 28 pages, 11 figures, 4 tables; minor changes compared to v1;
extended conclusion
Critical endpoint for deconfinement in matrix and other effective models
We consider the position of the deconfining critical endpoint, where the
first order transition for deconfinement is washed out by the presence of
massive, dynamical quarks. We use an effective matrix model, employed
previously to analyze the transition in the pure glue theory. If the param-
eters of the pure glue theory are unaffected by the presence of dynamical
quarks, and if the quarks only contribute perturbatively, then for three colors
and three degenerate quark flavors this quark mass is very heavy, m_de \sim 2.5
GeV, while the critical temperature, T_de, barely changes, \sim 1% below that
in the pure glue theory. The location of the deconfining critical endpoint is a
sensitive test to differentiate between effective models. For example, models
with a logarithmic potential for the Polyakov loop give much smaller values of
the quark mass, m_de \sim 1 GeV, and a large shift in T_de \sim 10% lower than
that in the pure glue theory.Comment: 16 pages; 3 figure
ODTN: Open Disaggregated Transport Network. Discovery and Control of a Disaggregated Optical Network through Open Source Software and Open APIs
ONOS discovers and manages a topology made of Transponders and a dedicated OLS, using standard protocols (NETCONF/RESTCONF) and models (OpenConfig/TAPI). The demo is a joint collaboration, towards production deployment, between 3 operators and 2 equipment vendors
Chiral Bosons Through Linear Constraints
We study in detail the quantization of a model which apparently describes
chiral bosons. The model is based on the idea that the chiral condition could
be implemented through a linear constraint. We show that the space of states is
of indefinite metric. We cure this disease by introducing ghost fields in such
a way that a BRST symmetry is generated. A quartet algebra is seen to emerge.
The quartet mechanism, then, forces all physical states, but the vacuum, to
have zero norm.Comment: 9 page
Equation of state in the PNJL model with the entanglement interaction
The equation of state and the phase diagram in two-flavor QCD are
investigated by the Polyakov-loop extended Nambu--Jona-Lasinio (PNJL) model
with an entanglement vertex between the chiral condensate and the
Polyakov-loop. The entanglement-PNJL (EPNJL) model reproduces LQCD data at zero
and finite chemical potential better than the PNJL model. Hadronic degrees of
freedom are taken into account by the free-hadron-gas (FHG) model with the
volume-exclusion effect due to the hadron generation. The EPNJL+FHG model
improves agreement of the EPNJL model with LQCD data particularly at small
temperature. The quarkyonic phase survives, even if the correlation between the
chiral condensate and the Polyakov loop is strong and hadron degrees of freedom
are taken into account. However, the location of the quarkyonic phase is
sensitive to the strength of the volume exclusion.Comment: 9 pages, 7 figure
Charges in Gauge Theories
In this article we investigate charged particles in gauge theories. After
reviewing the physical and theoretical problems, a method to construct charged
particles is presented. Explicit solutions are found in the Abelian theory and
a physical interpretation is given. These solutions and our interpretation of
these variables as the true degrees of freedom for charged particles, are then
tested in the perturbative domain and are demonstrated to yield infra-red
finite, on-shell Green's functions at all orders of perturbation theory. The
extension to collinear divergences is studied and it is shown that this method
applies to the case of massless charged particles. The application of these
constructions to the charged sectors of the standard model is reviewed and we
conclude with a discussion of the successes achieved so far in this programme
and a list of open questions.Comment: 47 pages, LaTeX, 14 figures, uses feynmp, necessary Metapost files
included. Review to appear in Pramana, Journal of Physics. Minor LaTeX change
to make page numbers visible on "Letter" paper forma
Holographic Roberge-Weiss Transitions
We investigate N=4 SYM coupled to fundamental flavours at nonzero imaginary
quark chemical potential in the strong coupling and large N limit, using
gauge/gravity duality applied to the D3-D7 system, treating flavours in the
probe approximation. The interplay between Z(N) symmetry and the imaginary
chemical potential yields a series of first-order Roberge-Weiss transitions. An
additional thermal transition separates phases where quarks are bound/unbound
into mesons. This results in a set of Roberge-Weiss endpoints: we establish
that these are triple points, determine the Roberge-Weiss temperature, give the
curvature of the phase boundaries and confirm that the theory is analytic in
mu^2 when mu^2~0.Comment: 37 pages, 13 figures; minor comments added, to appear in JHE
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