501 research outputs found
On the relation between Phi(1,2) and Phi(1,5) perturbed minimal models
We consider the RSOS S-matrices of the Phi(1,5) perturbed minimal models
which have recently been found in the companion paper [hep-th/9604098]. These
S-matrices have some interesting properties, in particular, unitarity may be
broken in a stronger sense than seen before, while one of the three classes of
Phi(1,5) perturbations (to be described) shares the same Thermodynamic Bethe
Ansatz as a related Phi(1,2) perturbation. We test these new S-matrices by the
standard Truncated Conformal Space method, and further observe that in some
cases the BA equations for two particle energy levels may be continued to
complex rapidity to describe (a) single particle excitations and (b) complex
eigenvalues of the Hamiltonian corresponding to non-unitary S-matrix elements.
We make some comments on identities between characters in the two related
models following from the fact that the two perturbed theories share the same
breather sector.Comment: LaTeX, 23 pages, 12 figures. Substantial revision of introductory
section, new discussion of complex eigenvalues and non-unitary S-matrice
A Rational Logarithmic Conformal Field Theory
We analyse the fusion of representations of the triplet algebra, the
maximally extended symmetry algebra of the Virasoro algebra at c=-2. It is
shown that there exists a finite number of representations which are closed
under fusion. These include all irreducible representations, but also some
reducible representations which appear as indecomposable components in fusion
products.Comment: 10 pages, LaTe
Correlation functions of disorder operators in massive ghost theories
The two-dimensional ghost systems with negative integral central charge
received much attention in the last years for their role in a number of
applications and in connection with logarithmic conformal field theory. We
consider the free massive bosonic and fermionic ghost systems and concentrate
on the non-trivial sectors containing the disorder operators. A unified
analysis of the correlation functions of such operators can be performed for
ghosts and ordinary complex bosons and fermions. It turns out that these
correlators depend only on the statistics although the scaling dimensions of
the disorder operators change when going from the ordinary to the ghost case.
As known from the study of the ordinary case, the bosonic and fermionic
correlation functions are the inverse of each other and are exactly expressible
through the solution of a non-linear differential equation.Comment: 8 pages, late
A Local Logarithmic Conformal Field Theory
The local logarithmic conformal field theory corresponding to the triplet
algebra at c=-2 is constructed. The constraints of locality and crossing
symmetry are explored in detail, and a consistent set of amplitudes is found.
The spectrum of the corresponding theory is determined, and it is found to be
modular invariant. This provides the first construction of a non-chiral
rational logarithmic conformal field theory, establishing that such models can
indeed define bona fide conformal field theories.Comment: 29 pages, LaTeX, minor changes, reference adde
Optical Spectroscopy of IRAS 02091+6333
We present a detailed spectroscopic investigation, spanning four winters, of
the asymptotic giant branch (AGB) star IRAS 02091+6333. Zijlstra & Weinberger
(2002) found a giant wall of dust around this star and modelled this unique
phenomenon. However their work suffered from the quality of the optical
investigations of the central object. Our spectroscopic investigation allowed
us to define the spectral type and the interstellar foreground extinction more
precisely. Accurate multi band photometry was carried out. This provides us
with the possibility to derive the physical parameters of the system. The
measurements presented here suggest a weak irregular photometric variability of
the target, while there is no evidence of a spectroscopic variability over the
last four years.Comment: 5 pages, Latex, 3 tables, 4 figures, Astron. & Astrophys. - in pres
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