52 research outputs found
Exact Symmetries realized on the Renormalized Group Flow
We show that symmetries are preserved exactly along the (Wilsonian)
renormalization group flow, though the IR cutoff deforms concrete forms of the
transformations. For a gauge theory the cutoff dependent Ward-Takahashi
identity is written as the master equation in the antifield formalism: one may
read off the renormalized BRS transformation from the master equation. The
Maxwell theory is studied explicitly to see how it works. The renormalized BRS
transformation becomes non-local but keeps off-shell nilpotency. Our formalism
is applicable for a generic global symmetry. The master equation considered for
the chiral symmetry provides us with the continuum analog of the
Ginsparg-Wilson relation and the L{\" u}scher's symmetry.Comment: Latex, 10 page
Gauge-Invariant Renormalization Group at Finite Temperature
We propose a gauge-invariant version of Wilson Renormalization Group for
thermal field theories in real time. The application to the computation of the
thermal masses of the gauge bosons in an SU(N) Yang-Mills theory is discussed.Comment: 23 pages, latex2e, 1 EPS figure. The discussions of BRS identities
and of the RG kernel have been modified. Final version, to appear on Nucl.
Phys.
Exact Renormalization Group in Algebraic Noncovariant Gauges
I study a class of Wilsonian formulations of non-Abelian gauge theories in
algebraic noncovariant gauges where the Wilsonian infrared cutoff is
inserted as a mass term for the propagating fields. In this way the
Ward-Takahashi identities are preserved to all scales. Nevertheless the
BRS-invariance in broken and the theory is gauge-dependent and unphysical at
. Then I discuss the infrared limit . I show that
the singularities of the axial gauge choice are avoided in planar gauge and in
light-cone gauge. Finally the rectangular Wilson loop of size is
evaluated at lowest order in perturbation theory and a noncommutativity between
the limits and is pointed out.Comment: 6 pages, latex2e, Proceeding of the Second Conference on the Exact R
Background field method in the Wilson formulation
A cutoff regularization for a pure Yang-Mills theory is implemented within
the background field method keeping explicit the gauge invariance of the
effective action. The method has been applied to compute the beta function at
one loop order.Comment: LaTex 13 pages, 1 figure; to appear in Nucl.Phys.
Critical Behavior of phi^4-Theory from the Thermal Renormalization Group
We discuss the universal critical behavior of a selfinteracting scalar field
theory at finite temperature as obtained from approximate solutions to
nonperturbative renormalization group (RG) equations. We employ a formulation
of the RG-equations in real-time formalism which is particularly well suited
for a discussion of the thermal behavior of theories which are weakly coupled
at T=0. We obtain the equation of state and critical exponents of the theory
with a few percent accuracy even for a relatively simple approximation to the
exact renormalization group equations.Comment: Revised version, to appear in Phys. Lett. B; References and
discussion adde
Axial anomalies in gauge theory by exact renormalization group method
The global chiral symmetry of a gauge theory is studied in the
framework of renormalization group (RG). The theory is defined by the RG flow
equations in the infrared cutoff \L and the boundary conditions for the
relevant couplings. The physical theory is obtained at \L=0. In our approach
the symmetry is implemented by choosing the boundary conditions for the
relevant couplings not at the ultraviolet point \L=\L_0\to\infty but at the
physical value \L=0. As an illustration, we compute the triangle axial
anomalies.Comment: 11 pages + 1 appended EPS figure, LaTeX, UPRF 94-39
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