34 research outputs found
Gauge fixing, zero--momentum modes and the calculation of masses on a lattice
It is shown that the zero--momentum modes can strongly affect the values of
the masses, for example the magnetic screening mass , calculated from
gauge--dependent correlators with zero momentum.Comment: 8 pages, uuencoded Latex file and one figure (eps-file
The photon propagator in compact QED_{2+1}: the effect of wrapping Dirac strings
We discuss the influence of closed Dirac strings on the photon propagator in
the Landau gauge emerging from a study of the compact U(1) gauge model in 2+1
dimensions. This gauge also minimizes the total length of the Dirac strings.
Closed Dirac strings are stable against local gauge-fixing algorithms only due
to the torus boundary conditions of the lattice. We demonstrate that these
left-over Dirac strings are responsible for the previously observed unphysical
behavior of the propagator of space-like photons (D_T) in the deconfinement
(high temperature) phase. We show how one can monitor the number N_3 of thermal
Dirac strings which allows to separate the propagator measurements into N_3
sectors. The propagator in N_3 \neq 0 sectors is characterized by a non--zero
mass and an anomalous dimension similarly to the confinement phase. Both mass
squared and anomalous dimension are found to be proportional to N_3.
Consequently, in the N_3=0 sector the unphysical behavior of the D_T photon
propagator is cured and the deviation from the free massless propagator
disappears.Comment: 13 pages, 13 figures, 1 tabl
Intertwining Operator Realization of the AdS/CFT Correspondence
We give a group-theoretic interpretation of the AdS/CFT correspondence as
relation of representation equivalence between representations of the conformal
group describing the bulk AdS fields and the coupled boundary fields
and . We use two kinds of equivalences. The first kind is
equivalence between bulk fields and boundary fields and is established here.
The second kind is the equivalence between coupled boundary fields. Operators
realizing the first kind of equivalence for special cases were given by Witten
and others - here they are constructed in a more general setting from the
requirement that they are intertwining operators. The intertwining operators
realizing the second kind of equivalence are provided by the standard conformal
two-point functions. Using both equivalences we find that the bulk field has in
fact two boundary fields, namely, the coupled boundary fields. Thus, from the
viewpoint of the bulk-boundary correspondence the coupled fields are on an
equal footing. Our setting is more general since our bulk fields are described
by representations of the Euclidean conformal group , induced from
representations of the maximal compact subgroup of . From
these large reducible representations we can single out representations which
are equivalent to conformal boundary representations labelled by the conformal
weight and by arbitrary representations of the Euclidean Lorentz group
, such that is contained in the restriction of to .
Thus, our boundary-to-bulk operators can be compared with those in the
literature only when for a fixed we consider a 'minimal' representation
containing .Comment: 25 pages, TEX file using harvmac.tex; v2: misprints corrected; to
appear in Nuclear Physics
Generalized Gravi-Electromagnetism
A self consistant and manifestly covariant theory for the dynamics of four
charges (masses) (namely electric, magnetic, gravitational, Heavisidian) has
been developed in simple, compact and consistent manner. Starting with an
invariant Lagrangian density and its quaternionic representation, we have
obtained the consistent field equation for the dynamics of four charges. It has
been shown that the present reformulation reproduces the dynamics of individual
charges (masses) in the absence of other charge (masses) as well as the
generalized theory of dyons (gravito - dyons) in the absence gravito - dyons
(dyons). key words: dyons, gravito - dyons, quaternion PACS NO: 14.80H
Mass gap and finite-size effects in finite temperature SU (2) lattice gauge theory
Engels J, Mitrjushkin VK. Mass gap and finite-size effects in finite temperature SU (2) lattice gauge theory. Physics Letters, B. 1992;282(3-4):415-422.This letter is devoted to the investigation of the point-point Polyakov loop correlators in SU (2) lattice gauge theory on 4Ns3 lattices with Ns=8, 12, 18 and 26. We use an analytic expression for point-point correlators provided by the transfer matrix formalism to study the temperature dependence of the mass gap [mu]m.g. and the corresponding matrix element [nu] near the critical point in a finite volume. The finite-size scaling analysis of the values [mu]m.g.([beta];Ns) obtained gives the possibility to extract the critical value [beta]c, the critical exponent [nu] and the surface tension [alpha]s.t