4,546 research outputs found
Field Strength Formulation of SU(2) Yang-Mills Theory in the Maximal Abelian Gauge: Perturbation Theory
We present a reformulation of SU(2) Yang-Mills theory in the maximal Abelian
gauge, where the non-Abelian gauge field components are exactly integrated out
at the expense of a new Abelian tensor field. The latter can be treated in a
semiclassical approximation and the corresponding saddle point equation is
derived. Besides the non-trivial solutions, which are presumably related to
non-perturbative interactions for the Abelian gauge field, the equation of
motion for the tensor fields allows for a trivial solution as well. We show
that the semiclassical expansion around this trivial solution is equivalent to
the standard perturbation theory. In particular, we calculate the one-loop
-function for the running coupling constant in this approach and
reproduce the standard result.Comment: 29 pages LaTeX, 6 postscript figures. Version to be published in Int.
J. Mod. Phys.
Systematic approach to cyclic orbifolds
We introduce an orbifold induction procedure which provides a systematic
construction of cyclic orbifolds, including their twisted sectors. The
procedure gives counterparts in the orbifold theory of all the
current-algebraic constructions of conformal field theory and enables us to
find the orbifold characters and their modular transformation properties.Comment: 39 pages, LaTeX. v2,3: references added. v4: typos correcte
The Orbifolds of Permutation-Type as Physical String Systems at Multiples of c=26 IV. Orientation Orbifolds Include Orientifolds
In this fourth paper of the series, I clarify the somewhat mysterious
relation between the large class of {\it orientation orbifolds} (with twisted
open-string CFT's at ) and {\it orientifolds} (with untwisted open
strings at ), both of which have been associated to division by
world-sheet orientation-reversing automorphisms. In particular -- following a
spectral clue in the previous paper -- I show that, even as an {\it interacting
string system}, a certain half-integer-moded orientation orbifold-string system
is in fact equivalent to the archetypal orientifold. The subtitle of this
paper, that orientation orbifolds include and generalize standard orientifolds,
then follows because there are many other orientation orbifold-string systems
-- with higher fractional modeing -- which are not equivalent to untwisted
string systems.Comment: 22 pages, typos correcte
Cyclic Coset Orbifolds
We apply the new orbifold duality transformations to discuss the special case
of cyclic coset orbifolds in further detail. We focus in particular on the case
of the interacting cyclic coset orbifolds, whose untwisted sectors are
Z_\lambda(permutation)-invariant g/h coset constructions which are not \lambda
copies of coset constructions. Because \lambda copies are not involved, the
action of Z_\lambda(permutation) in the interacting cyclic coset orbifolds can
be quite intricate. The stress tensors and ground state conformal weights of
all the sectors of a large class of these orbifolds are given explicitly and
special emphasis is placed on the twisted h subalgebras which are generated by
the twisted (0,0) operators of these orbifolds. We also discuss the systematics
of twisted (0,0) operators in general coset orbifolds.Comment: 30 page
Vertex Operators in 2K Dimensions
A formula is proposed which expresses free fermion fields in 2K dimensions in
terms of the Cartan currents of the free fermion current algebra. This leads,
in an obvious manner, to a vertex operator construction of nonabelian free
fermion current algebras in arbitrary even dimension. It is conjectured that
these ideas may generalize to a wide class of conformal field theories.Comment: Minor change in notation. Change in references
Exact renormalization group equations and the field theoretical approach to critical phenomena
After a brief presentation of the exact renormalization group equation, we
illustrate how the field theoretical (perturbative) approach to critical
phenomena takes place in the more general Wilson (nonperturbative) approach.
Notions such as the continuum limit and the renormalizability and the presence
of singularities in the perturbative series are discussed.Comment: 15 pages, 7 figures, to appear in the Proceedings of the 2nd
Conference on the Exact Renormalization Group, Rome 200
PSR J2229+6114: Discovery of an Energetic Young Pulsar in the Error Box of the EGRET Source 3EG J2227+6122
We report the detection of radio and X-ray pulsations at a period of 51.6 ms
from the X-ray source RX/AX J2229.0+6114 in the error box of the EGRET source
3EG J2227+6122. An ephemeris derived from a single ASCA observation and
multiple epochs at 1412 MHz from Jodrell Bank indicates steady spin-down with
P-dot = 7.83 x 10^(-14) s/s. From the measured P and P-dot we derive spin-down
power E-dot = 2.2 x 10^(37) erg/s, magnetic field B = 2.0 x 10^(12) G, and
characteristic age P/2P-dot = 10,460 yr. An image from the Chandra X-ray
Observatory reveals a point source surrounded by centrally peaked diffuse
emission that is contained within an incomplete radio shell. We assign the name
G106.6+2.9 to this new supernova remnant, which is evidently a pulsar wind
nebula. For a distance of 3 kpc estimated from X-ray absorption, the ratio of
X-ray luminosity to spin-down power is ~8 x 10^(-5), smaller than that of most
pulsars, but similar to the Vela pulsar. If PSR J2229+6114 is the counterpart
of 3EG J2227+6122 then its efficiency of gamma-ray production, if isotropic, is
0.016 (d/3 kpc)^2. It obeys an established trend of gamma-ray efficiency among
known gamma-ray pulsars which, in combination with the demonstrated absence of
any other plausible counterpart for 3EG J2227+6122, makes the identification
compelling. If confirmed, this identification bolsters the pulsar model for
unidentified Galactic EGRET sources.Comment: 5 pages, 4 figures, accepted by The Astrophysical Journal Letter
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