7,888 research outputs found
Two Large Examples in Orbifold Theory: Abelian Orbifolds and the Charge Conjugation Orbifold on su(n)
Recently the operator algebra and twisted vertex operator equations were
given for each sector of all WZW orbifolds, and a set of twisted KZ equations
for the WZW permutation orbifolds were worked out as a large example. In this
companion paper we report two further large examples of this development. In
the first example we solve the twisted vertex operator equations in an abelian
limit to obtain the twisted vertex operators and correlators of a large class
of abelian orbifolds. In the second example, the twisted vertex operator
equations are applied to obtain a set of twisted KZ equations for the
(outer-automorphic) charge conjugation orbifold on su(n \geq 3).Comment: 58 pages, v2: three minor typo
Computations in Large N Matrix Mechanics
The algebraic formulation of Large N matrix mechanics recently developed by
Halpern and Schwartz leads to a practical method of numerical computation for
both action and Hamiltonian problems. The new technique posits a boundary
condition on the planar connected parts X_w, namely that they should decrease
rapidly with increasing order. This leads to algebraic/variational schemes of
computation which show remarkably rapid convergence in numerical tests on some
many- matrix models. The method allows the calculation of all moments of the
ground state, in a sequence of approximations, and excited states can be
determined as well. There are two unexpected findings: a large d expansion and
a new selection rule for certain types of interaction.Comment: 27 page
Ward Identities for Affine-Virasoro Correlators
Generalizing the Knizhnik-Zamolodchikov equations, we derive a hierarchy of
non-linear Ward identities for affine-Virasoro correlators. The hierarchy
follows from null states of the Knizhnik-Zamolodchikov type and the assumption
of factorization, whose consistency we verify at an abstract level. Solution of
the equations requires concrete factorization ans\"atze, which may vary over
affine-Virasoro space. As a first example, we solve the non-linear equations
for the coset constructions, using a matrix factorization. The resulting coset
correlators satisfy first-order linear partial differential equations whose
solutions are the coset blocks defined by Douglas.Comment: 53 pages, Latex, LBL-32619, UCB-PTH-92/24, BONN-HE-92/2
Flat Connections and Non-Local Conserved Quantities in Irrational Conformal Field Theory
Irrational conformal field theory (ICFT) includes rational conformal field
theory as a small subspace, and the affine-Virasoro Ward identities describe
the biconformal correlators of ICFT. We reformulate the Ward identities as an
equivalent linear partial differential system with flat connections and new
non-local conserved quantities. As examples of the formulation, we solve the
system of flat connections for the coset correlators, the correlators of the
affine-Sugawara nests and the high-level -point correlators of ICFT.Comment: 40 pages, Latex, UCB-PTH-93/33, LBL-34901, CPTH-A277.129
Solving the Ward Identities of Irrational Conformal Field Theory
The affine-Virasoro Ward identities are a system of non-linear differential
equations which describe the correlators of all affine-Virasoro constructions,
including rational and irrational conformal field theory. We study the Ward
identities in some detail, with several central results. First, we solve for
the correlators of the affine-Sugawara nests, which are associated to the
nested subgroups . We also find an
equivalent algebraic formulation which allows us to find global solutions
across the set of all affine-Virasoro constructions. A particular global
solution is discussed which gives the correct nest correlators, exhibits
braiding for all affine-Virasoro correlators, and shows good physical behavior,
at least for four-point correlators at high level on simple . In rational
and irrational conformal field theory, the high-level fusion rules of the
broken affine modules follow the Clebsch-Gordan coefficients of the
representations.Comment: 45 pages, Latex, UCB-PTH-93/18, LBL-34111, BONN-HE-93/17. We
factorize the biconformal nest correlators of the first version, obtaining
the conformal correlators of the affine-Sugawara nests on g/h_1/.../h_
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
Semi-Classical Blocks and Correlators in Rational and Irrational Conformal Field Theory
The generalized Knizhnik-Zamolodchikov equations of irrational conformal
field theory provide a uniform description of rational and irrational conformal
field theory. Starting from the known high-level solution of these equations,
we first construct the high-level conformal blocks and correlators of all the
affine-Sugawara and coset constructions on simple g. Using intuition gained
from these cases, we then identify a simple class of irrational processes whose
high-level blocks and correlators we are also able to construct.Comment: 53 pages, Latex. Revised version with extended discussion of phases
and secondarie
The Lie h-Invariant Conformal Field Theories and the Lie h-Invariant Graphs
We use the Virasoro master equation to study the space of Lie h-invariant
conformal field theories, which includes the standard rational conformal field
theories as a small subspace. In a detailed example, we apply the general
theory to characterize and study the Lie h-invariant graphs, which classify the
Lie h-invariant conformal field theories of the diagonal ansatz on SO(n). The
Lie characterization of these graphs is another aspect of the recently observed
Lie group-theoretic structure of graph theory.Comment: 38p
X-ray Observations and Infrared Identification of the Transient 7.8 s X-ray Binary Pulsar XTE J1829-098
XMM-Newton and Chandra observations of the transient 7.8 s pulsar XTE
J1829-098 are used to characterize its pulse shape and spectrum, and to
facilitate a search for an optical or infrared counterpart. In outburst, the
absorbed, hard X-ray spectrum with Gamma = 0.76+/-0.13 and N_H = (6.0+/-0.6) x
10^{22} cm^{-2} is typical of X-ray binary pulsars. The precise Chandra
localization in a faint state leads to the identification of a probable
infrared counterpart at R.A. = 18h29m43.98s, decl. = -09o51'23.0" (J2000.0)
with magnitudes K=12.7, H=13.9, I>21.9, and R>23.2. If this is a highly
reddened O or B star, we estimate a distance of 10 kpc, at which the maximum
observed X-ray luminosity is 2x10^{36} ergs s^{-1}, typical of Be X-ray
transients or wind-fed systems. The minimum observed luminosity is
3x10^{32}(d/10 kpc)^2 ergs s^{-1}. We cannot rule out the possibility that the
companion is a red giant. The two known X-ray outbursts of XTE J1829-098 are
separated by ~1.3 yr, which may be the orbital period or a multiple of it, with
the neutron star in an eccentric orbit. We also studied a late M-giant
long-period variable that we found only 9" from the X-ray position. It has a
pulsation period of ~1.5 yr, but is not the companion of the X-ray source.Comment: 6 pages, 7 figures. To appear in The Astrophysical Journa
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