148 research outputs found
On the possibility of exotic supersymmetry in two dimensional Conformal Field Theory
We investigate the possibility to construct extended parafermionic conformal
algebras whose generating current has spin , generalizing the
superconformal (spin 3/2) and the Fateev Zamolodchikov (spin 4/3) algebras.
Models invariant under such algebras would possess exotic supersymmetries
satisfying (supercharge) = (momentum). However, we show that for this
new algebra allows only for models at , for it is a trivial
rephrasing of the ordinary parafermionic model, for (and,
requiring unitarity, for all larger ) such algebras do not exist.
Implications of this result for existence of exotic supersymmetry in two
dimensional field theory are discussed.Comment: 21p
Dynkin TBA's
We prove a useful identity valid for all minimal S-matrices, that
clarifies the transformation of the relative thermodynamic Bethe Ansatz (TBA)
from its standard form into the universal one proposed by Al.B.Zamolodchikov.
By considering the graph encoding of the system of functional equations for the
exponentials of the pseudoenergies, we show that any such system having the
same form as those for the TBA's, can be encoded on only.
This includes, besides the known diagonal scattering, the set of all
related {\em magnonic} TBA's. We explore this class sistematically and
find some interesting new massive and massless RG flows. The generalization to
classes related to higher rank algebras is briefly presented and an intriguing
relation with level-rank duality is signalled.Comment: 29 pages, Latex (no macros) DFUB-92-11, DFTT-31/9
A New Family of Diagonal Ade-Related Scattering Theories
We propose the factorizable S-matrices of the massive excitations of the
non-unitary minimal model perturbed by the operator .
The massive excitations and the whole set of two particle S-matrices of the
theory is simply related to the unitary minimal scattering theory. The
counting argument and the Thermodynamic Bethe Ansatz (TBA) are applied to this
scattering theory in order to support this interpretation. Generalizing this
result, we describe a new family of NON UNITARY and DIAGONAL -related
scattering theories. A further generalization suggests the magnonic TBA for a
large class of non-unitary \G\otimes\G/\G coset models
(\G=A_{odd},D_n,E_{6,7,8}) perturbed by , described by
non-diagonal S-matrices.Comment: 13 pages, Latex (no macros), DFUB-92-12, DFTT/30-9
ADE functional dilogarithm identities and integrable models
We describe a new infinite family of multi-parameter functional equations for
the Rogers dilogarithm, generalizing Abel's and Euler's formulas. They are
suggested by the Thermodynamic Bethe Ansatz approach to the Renormalization
Group flow of 2D integrable, ADE-related quantum field theories. The known sum
rules for the central charge of critical fixed points can be obtained as
special cases of these. We conjecture that similar functional identities can be
constructed for any rational integrable quantum field theory with factorized
S-matrix and support it with extensive numerical checks.Comment: LaTeX, 9 pages, no figure
Generalized KdV and Quantum Inverse Scattering Description of Conformal Minimal Models
We propose an alternative description of 2 dimensional Conformal Field Theory
in terms of Quantum Inverse Scattering. It is based on the generalized KdV
systems attached to , yielding the classical limit of Virasoro as
Poisson bracket structure. The corresponding T-system is shown to coincide with
the one recently proposed by Kuniba and Suzuki. We classify the primary
operators of the minimal models that commute with all the Integrals of Motion,
and that are therefore candidates to perturb the model by keeping the
conservation laws. For our structure these happen to be
, in contrast to the case,
studied by Bazhanov, Lukyanov and Zamolodchikov~\cite{BLZ}, related to
.Comment: 12 pages, latex. 1 reference adde
Scaling Functions in the Odd Charge Sector of Sine-Gordon/Massive Thirring Theory
A non-linear integral equation (NLIE) governing the finite size effects of
excited states of even topological charge in the sine-Gordon (sG) / massive
Thirring (mTh) field theory, deducible from a light-cone lattice formulation of
the model, has been known for some time. In this letter we conjecture an
extension of this NLIE to states with odd topological charge, thus completing
the spectrum of the theory. The scaling functions obtained as solutions to our
conjectured NLIE are compared successfully with Truncated Conformal Space data
and the construction is shown to be compatible with all other facts known about
the local Hilbert spaces of sG and mTh models. With the present results we have
achieved a full control over the finite size behaviour of energy levels of
sG/mTh theory.Comment: LaTeX2e, 12 pp., 3 eps figs. Remarks on locality adde
On the hydrodynamics of unstable excitations
The generalized hydrodynamic (GHD) approach has been extremely successful in describing the out-of-equilibrium properties of a great variety of integrable many-body quantum systems. It naturally extracts the large-scale dynamical degrees of freedom of the system, and is thus a particularly good probe for emergent phenomena. One such phenomenon is the presence of unstable particles, traditionally seen via special analytic structures of the scattering matrix. Because of their finite lifetime and energy threshold, these are especially hard to study. In this paper we apply the GHD approach to a model possessing both unstable excitations and quantum integrability. The largest family of relativistic integrable quantum field theories known to have these features are the homogeneous sine-Gordon models. We consider the simplest non-trivial example of such theories and investigate the effect of an unstable excitation on various physical quantities, both at equilibrium and in the non-equilibrium state arising from the partitioning protocol. The hydrodynamic approach sheds new light onto the physics of the unstable particle, going much beyond its definition via the analytic structure of the scattering matrix, and clarifies its effects both on the equilibrium and out-of-equilibrium properties of the theory. Crucially, within this dynamical perspective, we identify unstable particles as finitely-lived bound states of co-propagating stable particles of different types, and observe how stable populations of unstable particles emerge in large-temperature thermal baths
On the Thermodynamic Bethe Ansatz Equation in Sinh-Gordon Model
Two implicit periodic structures in the solution of sinh-Gordon thermodynamic
Bethe ansatz equation are considered. The analytic structure of the solution as
a function of complex is studied to some extent both analytically and
numerically. The results make a hint how the CFT integrable structures can be
relevant in the sinh-Gordon and staircase models. More motivations are figured
out for subsequent studies of the massless sinh-Gordon (i.e. Liouville) TBA
equation.Comment: 32 pages, 18 figures, myart.st
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