scholarly journals Fixed points and D-branes

2013 ◽  
Vol 94 (108) ◽  
pp. 169-180
Author(s):  
Elaine Beltaos
Keyword(s):  
Fixed Point ◽  
Field Theories ◽  
Conformal Field Theories ◽  
Point Property ◽  
Integer Matrix ◽  
Matrix Representations ◽  
Fusion Ring ◽  
Conformal Field ◽  
S Matrix ◽  
Structure Constants

The affine Kac-Moody algebras give rise to rational conformal field theories (RCFTs) called the Wess-Zumino-Witten (WZW) models. An important component of an RCFT is its fusion ring, whose structure constants are given by the associated S-matrix. We apply a fixed point property possessed by the WZW models ("fixed point factorization") to calculate nonnegative integer matrix representations of the fusion ring, allowing for the calculation of D-brane charges in string theory.

scholarly journals On 2d CFTs that interpolate between minimal models

2019 ◽  
Vol 6 (6) ◽  
Author(s):  
Sylvain Ribault
Keyword(s):  
Correlation Functions ◽  
Central Charge ◽  
Field Theories ◽  
Two Dimensional ◽  
Conformal Field Theories ◽  
Minimal Models ◽  
Conformal Blocks ◽  
Conformal Field ◽  
Exactly Solvable ◽  
Structure Constants

We investigate exactly solvable two-dimensional conformal field theories that exist at generic values of the central charge, and that interpolate between A-series or D-series minimal models. When the central charge becomes rational, correlation functions of these CFTs may tend to correlation functions of minimal models, or diverge, or have finite limits which can be logarithmic. These results are based on analytic relations between four-point structure constants and residues of conformal blocks.

SOME LANDAU-GINZBURG MODELS FROM CONFORMAL FIELD THEORY

1990 ◽  
Vol 05 (12) ◽  
pp. 2343-2358 ◽  
Author(s):  
KEKE LI
Keyword(s):  
Field Theory ◽  
Fixed Point ◽  
Conformal Field Theory ◽  
Current Algebra ◽  
Operator Algebra ◽  
Field Theories ◽  
Conformal Field Theories ◽  
Conformal Field ◽  
Coset Models ◽  
Marginal Deformation

A method of constructing critical (fixed point) Landau-Ginzburg action from operator algebra is applied to several classes of conformal field theories, including lines of c = 1 models and the coset models based on SU(2) current algebra. For the c = 1 models, the Landau-Ginzberg potential is argued to be physically consistent, and it resembles a modality-one singularity with modal deformation representing exactly the marginal deformation. The potentials for the coset models manifestly possess correct discrete symmetries.

scholarly journals SINE-GORDON VS. MASSIVE THIRRING

1993 ◽  
Vol 08 (23) ◽  
pp. 4131-4174 ◽  
Author(s):  
TIMOTHY R. KLASSEN ◽  
EZER MELZER
Keyword(s):  
Energy Levels ◽  
Gaussian Model ◽  
Field Theories ◽  
Partition Functions ◽  
Quantum Field Theories ◽  
Conformal Field Theories ◽  
Minimal Models ◽  
Conformal Field ◽  
Fermion Fields ◽  
S Matrix

By viewing the sine-Gordon and massive Thirring models as perturbed conformal field theories, one sees that they are different (the difference being observable, for instance, in finite-volume energy levels). The UV limit of the former (SGM) is a Gaussian model, that of the latter (MTM) a so-called fermionic Gaussian model, the compactification radius of the boson underlying both theories depending on the SG/MT coupling. (These two families of conformal field theories are related by a “twist”.) Corresponding SG and MT models contain a subset of fields with identical correlation functions, but each model also has fields the other one does not have; for example, the fermion fields of MTM are not contained in SGM, and the bosonic soliton fields of SGM are not in MTM. Our results imply, in particular, that the SGM at the so-called “free-Dirac point” β2=4π is actually a theory of two interacting bosons with diagonal S-matrix S=−1, and that for arbitrary couplings the overall sign of the accepted SG S-matrix in the soliton sector should be reversed. More generally, we draw attention to the existence of new classes of quantum field theories, analogs of the (perturbed) fermionic Gaussians models, whose partition functions are invariant only under a subgroup of the modular group. One such class comprises “fermionic versions” of the Virasoro minimal models.

scholarly journals SIMPLE CURRENTS, MODULAR INVARIANTS AND FIXED POINTS

1990 ◽  
Vol 05 (15) ◽  
pp. 2903-2952 ◽  
Author(s):  
A.N. SCHELLEKENS ◽  
S. YANKIELOWICZ
Keyword(s):  
Field Theory ◽  
Fixed Point ◽  
Fixed Points ◽  
Field Theories ◽  
Partition Functions ◽  
Conformal Field Theories ◽  
Modular Invariant ◽  
Conformal Field ◽  
Modular Invariants ◽  
Simple Currents

We review the use of simple currents in constructing modular invariant partition functions and the problem of resolving their fixed points. We present some new results, in particular regarding fixed point resolution. Additional empirical evidence is provided in support of our conjecture that fixed points are always related to some conformal field theory. We complete the identification of the fixed point conformal field theories for all simply laced and most non-simply laced Kac-Moody algebras, for which the fixed point CFT’s turn out to be Kac-Moody algebras themselves. For the remaining non-simply laced ones we obtain spectra that appear to correspond to new non-unitary conformal field theories. The fusion rules of the simplest unidentified example are computed.

scholarly journals Holographic entanglement entropy in cutoff AdS

2018 ◽  
Vol 33 (36) ◽  
pp. 1850226 ◽  
Author(s):  
Chanyong Park
Keyword(s):  
Fixed Point ◽  
Entanglement Entropy ◽  
Three Dimensional ◽  
Energy Scale ◽  
Field Theories ◽  
Dimensional Sphere ◽  
Conformal Field Theories ◽  
Conformal Field ◽  
Holographic Entanglement Entropy ◽  
Length Contraction

We investigate the holographic entanglement entropy of deformed conformal field theories which are dual to a cutoff AdS space. The holographic entanglement entropy evaluated on a three-dimensional Poincaré AdS space with a finite cutoff can be reinterpreted as that of the dual field theory deformed by either a boost or [Formula: see text] deformation. For the boost case, we show that, although it trivially acts on the underlying theory, it nontrivially affects the entanglement entropy due to the length contraction. For a three-dimensional AdS, we show that the effect of the boost transformation can be reinterpreted as the rescaling of the energy scale, similar to the [Formula: see text] deformation. Under the boost and [Formula: see text] deformation, the [Formula: see text]-function of the entanglement entropy exactly shows the features expected by the Zamolodchikov’s [Formula: see text]-theorem. The deformed theory is always stationary at a UV fixed point and monotonically flows to another CFT in the IR fixed point. We also show that the holographic entanglement entropy in a Poincaré cutoff AdS space can reproduce the exact same result of the [Formula: see text] deformed theory on a two-dimensional sphere.

scholarly journals DILOGARITHM IDENTITIES, FUSION RULES AND STRUCTURE CONSTANTS OF CFTs

1994 ◽  
Vol 09 (02) ◽  
pp. 133-141 ◽  
Author(s):  
MICHAEL TERHOEVEN
Keyword(s):  
Central Charge ◽  
Field Theories ◽  
Conformal Field Theories ◽  
Fusion Rules ◽  
Conformal Field ◽  
Physics Literature ◽  
Structure Constants ◽  
Quantum Dimensions ◽  
Infinite Set ◽  
Modular Covariance

Recently dilogarithm identities have made their appearance in the physics literature. These identities seem to allow to calculate structure constants like, in particular, the effective central charge of certain conformal field theories from their fusion rules. In Ref. 12 a proof of identities of this type was given by considering the asymptotics of character functions in the so-called Rogers-Ramanujan sum form and comparing with the asymptotics predicted by modular covariance. Refining the argument, we obtain the general connection of quantum dimensions of certain conformal field theories to the arguments of the dilogarithm function in the identities in question and an infinite set of consistency conditions on the parameters of Rogers-Ramanujan type partitions for them to be modular covariant.

THREE-POINT CORRELATION FUNCTIONS OF THE MINIMAL CONFORMAL THEORIES COUPLED TO 2D GRAVITY

1991 ◽  
Vol 06 (39) ◽  
pp. 3601-3612 ◽  
Author(s):  
Vl. S. DOTSENKO
Keyword(s):  
Operator Algebra ◽  
Correlation Functions ◽  
2D Gravity ◽  
Coulomb Gas ◽  
Field Theories ◽  
Algebra Structure ◽  
Conformal Field Theories ◽  
Conformal Field ◽  
Point Correlation ◽  
Structure Constants

The general three-point correlation functions of the minimal conformal field theories coupled to gravity are calculated using the specific Coulomb gas type quantization technique. The gravity interaction modifies in an essential way the operator algebra of the corresponding minimal model, in particular in canceling the decoupling of a finite number of primary fields, in case of rational theories. This is suggested to be related to the appearance of new physical states, under the BRST analysis of Lian and Zuckerman. Within the analytic technique, this effect is due to the corresponding singularities of the gravity sector operator algebra structure constants.

scholarly journals Defects and perturbation

2021 ◽  
Vol 2021 (4) ◽  
Author(s):  
Enrico M. Brehm
Keyword(s):  
Entanglement Entropy ◽  
Topological Defects ◽  
Field Theories ◽  
Two Dimensional ◽  
Conformal Field Theories ◽  
Minimal Models ◽  
Conformal Field

Abstract We investigate perturbatively tractable deformations of topological defects in two-dimensional conformal field theories. We perturbatively compute the change in the g-factor, the reflectivity, and the entanglement entropy of the conformal defect at the end of these short RG flows. We also give instances of such flows in the diagonal Virasoro and Super-Virasoro Minimal Models.

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