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Ladder-QCD at finite isospin chemical potential
We use an effective QCD model (ladder-QCD) to explore the phase diagram for
chiral symmetry breaking and restoration at finite temperature with different
quark chemical potentials. In agreement with a recent investigation based
on the Nambu-Jona-Lasinio model, we find that a finite pion condensate shows up
for high enough isospin chemical potential . For
small the phase diagram in the plane shows two first
order transition lines and two critical ending points.Comment: Typed in RevTex4, pages 12, figures 2. Two references adde
Symmetries and Motions in Manifolds
In these lectures the relations between symmetries, Lie algebras, Killing
vectors and Noether's theorem are reviewed. A generalisation of the basic ideas
to include velocity-dependend co-ordinate transformations naturally leads to
the concept of Killing tensors. Via their Poisson brackets these tensors
generate an {\em a priori} infinite-dimensional Lie algebra. The nature of such
infinite algebras is clarified using the example of flat space-time. Next the
formalism is extended to spinning space, which in addition to the standard real
co-ordinates is parametrized also by Grassmann-valued vector variables. The
equations for extremal trajectories (`geodesics') of these spaces describe the
pseudo-classical mechanics of a Dirac fermion. We apply the formalism to solve
for the motion of a pseudo-classical electron in Schwarzschild space-time.Comment: 19 pages. Lectures at 28th Winter School of Theoretical Physics,
Karpacz (Poland, 1992) by J.W. van Holte
Particles with anomalous magnetic moment in external e.m. fields: the proper time formulation
In this paper we evaluate the expression for the Green function of a
pseudo-classical spinning particle interacting with constant electromagnetic
external fields by taking into account the anomalous magnetic and electric
moments of the particle. The spin degrees of freedom are described in terms of
Grassmann variables and the evolution operator is obtained through the
Fock-Schwinger proper time method.Comment: 10 page
Spinning particle in an external linearized gravitational wave field
We study the interaction of a scalar and a spinning particle with a coherent
linearized gravitational wave field treated as a classical spin two external
field. The spin degrees of freedom of the spinning particle are described by
skew-commuting variables. We derive the explicit expressions for the
eigenfunctions and the Green's functions of the theory. The discussion is exact
within the approximation of neglecting radiative corrections and we prove that
the result is completely determined by the semiclassical contribution.Comment: 11 page
A large Nc perspective on the QCD phase diagram
The transition between the hadronic phase and the quark gluon plasma phase at
nonzero temperature and quark chemical potentials is studied within the
large-Nc expansion of QCD.Comment: 5 page
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