4,889 research outputs found
Confinement- Deconfinement Phase Transition and Fractional Instanton Quarks in Dense Matter
We present arguments suggesting that large size overlapping instantons are
the driving mechanism of the confinement-deconfinement phase transition at
nonzero chemical potential mu. The arguments are based on the picture that
instantons at very large chemical potential in the weak coupling regime are
localized configurations with finite size \rho\sim\mu^{-1}. At the same time,
the same instantons at smaller chemical potential in the strong coupling regime
are well represented by the so-called instanton-quarks with fractional
topological charge 1/N_c. We estimate the critical chemical potential mu_c(T)
where transition between these two regimes takes place. We identify this
transition with confinement- deconfinement phase transition.
We also argue that the instanton quarks carry magnetic charges. As a
consequence of it, there is a relation between our picture and the standard
t'Hooft and Mandelstam picture of the confinement. We also comment on possible
relations of instanton-quarks with "periodic instantons", " center vortices",
and "fractional instantons" in the brane construction. We also argue that the
variation of the external parameter mu, which plays the role of the vacuum
expectation value of a "Higgs" field at mu >> \Lambda_{QCD}, allows to study
the transition from a "Higgs -like" gauge theory (weak coupling regime, mu>>
\Lambda_{QCD}) to ordinary QCD (strong coupling regime, mu<< \Lambda_{QCD}). We
also comment on some recent lattice results on topological charge density
distribution which support our picture.Comment: Invited talk delivered at the Light Cone Workshop, July 7-15, 2005,
Cairns, Australi
Topological Defects in QCD at large Baryon Density and/or large
The main leitmotiv of the present talk is analysis of different topological
objects such as strings and domain walls in QCD. As it is well known, the
standard model in general (and QCD in particular) does not support any kind of
such objects due to some simple topological arguments. However, the situation
cardinally changes when one considers QCD in large limit or in the limit
of large baryon density when the unique light field emerges. I discuss
- domain walls and global strings which occur in both systems:
in high density QCD and in QCD at large .
I also discuss the effects of quantum anomalies in the presence of
topological objects in high-density QCD. The anomaly induced interactions lead
to a number of interesting phenomena (such as the induced currents along the
strings) which may have phenomenological consequences observable in neutron
stars.Comment: Invited talk at the workshop "large N_c QCD", July, 5-9, 2004,
Trento, to be published in the Proceeding
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