245 research outputs found

### Correlation Functions Along a Massless Flow

A non-perturbative method based on the Form Factor bootstrap approach is
proposed for the analysis of correlation functions of 2-D massless integrable
theories and applied to the massless flow between the Tricritical and the
Critical Ising Models.Comment: 11 pages (two figures not included in the text), Latex file,
ISAS/EP/94/15

### On Perturbations of Unitary Minimal Models by Boundary Condition Changing Operators

In this note we consider boundary perturbations in the A-Series unitary
minimal models by phi_{r,r+2} fields on superpositions of boundaries. In
particular, we consider perturbations by boundary condition changing operators.
Within conformal perturbation theory we explicitly map out the space of
perturbative renormalisation group flows for the example phi_{1,3} and find
that this sheds light on more general phi_{r,r+2} perturbations. Finally, we
find a simple diagrammatic representation for the space of flows from a single
Cardy boundary condition.Comment: 27 pages, 10 figure

### Conformal Field Theory and Hyperbolic Geometry

We examine the correspondence between the conformal field theory of boundary
operators and two-dimensional hyperbolic geometry. By consideration of domain
boundaries in two-dimensional critical systems, and the invariance of the
hyperbolic length, we motivate a reformulation of the basic equation of
conformal covariance. The scale factors gain a new, physical interpretation. We
exhibit a fully factored form for the three-point function. A doubly-infinite
discrete series of central charges with limit c=-2 is discovered. A
correspondence between the anomalous dimension and the angle of certain
hyperbolic figures emerges. Note: email after 12/19: [email protected]: 7 pages (PlainTeX

### Comment on "Phase Diagram of an Asymmetric Spin Ladder."

A comment to the paper by S. Chen, H. B\"uttner, and J. Voit, [Phys. Rev.
Lett. {\bf 87}, 087205 (2001)].Comment: 1 page, 1 figure, to appear in Physical Review Letter

### Asymptotic factorisation of form factors in two-dimensional quantum field theory

It is shown that the scaling operators in the conformal limit of a
two-dimensional field theory have massive form factors which obey a simple
factorisation property in rapidity space. This has been used to identify such
operators within the form factor bootstrap approach. A sum rule which yields
the scaling dimension of such operators is also derived.Comment: 11 pages, late

### Strong Conformal Dynamics at the LHC and on the Lattice

Conformal technicolor is a paradigm for new physics at LHC that may solve the
problems of strong electroweak symmetry breaking for quark masses and precision
electroweak data. We give explicit examples of conformal technicolor theories
based on a QCD-like sector. We suggest a practical method to test the conformal
dynamics of these theories on the lattice.Comment: v2: Generalized discussion of lattice measurement of hadron masses,
references added, minor clarifications v3: references added, minor change

### Free boson formulation of boundary states in W_3 minimal models and the critical Potts model

We develop a Coulomb gas formalism for boundary conformal field theory having
a $W$ symmetry and illustrate its operation using the three state Potts model.
We find that there are free-field representations for six $W$ conserving
boundary states, which yield the fixed and mixed physical boundary conditions,
and two $W$ violating boundary states which yield the free and new boundary
conditions. Other $W$ violating boundary states can be constructed but they
decouple from the rest of the theory. Thus we have a complete free-field
realization of the known boundary states of the three state Potts model. We
then use the formalism to calculate boundary correlation functions in various
cases. We find that the conformal blocks arising when the two point function of
$\phi_{2,3}$ is calculated in the presence of free and new boundary conditions
are indeed the last two solutions of the sixth order differential equation
generated by the singular vector.Comment: 25 page

### Open-closed field algebras

We introduce the notions of open-closed field algebra and open-closed field
algebra over a vertex operator algebra V. In the case that V satisfies certain
finiteness and reductivity conditions, we show that an open-closed field
algebra over V canonically gives an algebra over a \C-extension of the
Swiss-cheese partial operad. We also give a tensor categorical formulation and
categorical constructions of open-closed field algebras over V.Comment: 55 pages, largely revised, an old subsection is deleted, a few
references are adde

### The triangular Ising model with nearest- and next-nearest-neighbor couplings in a field

We study the Ising model on the triangular lattice with nearest-neighbor
couplings $K_{\rm nn}$, next-nearest-neighbor couplings $K_{\rm nnn}>0$, and a
magnetic field $H$. This work is done by means of finite-size scaling of
numerical results of transfer matrix calculations, and Monte Carlo simulations.
We determine the phase diagram and confirm the character of the critical
manifolds. The emphasis of this work is on the antiferromagnetic case $K_{\rm
nn}<0$, but we also explore the ferromagnetic regime $K_{\rm nn}\ge 0$ for H=0.
For $K_{\rm nn}<0$ and H=0 we locate a critical phase presumably covering the
whole range $-\infty < K_{\rm nn}<0$. For $K_{\rm nn}<0$, $H\neq 0$ we locate a
plane of phase transitions containing a line of tricritical three-state Potts
transitions. In the limit $H \to \infty$ this line leads to a tricritical model
of hard hexagons with an attractive next-nearest-neighbor potential

### Reaction-controlled diffusion: Monte Carlo simulations

We study the coupled two-species non-equilibrium reaction-controlled
diffusion model introduced by Trimper et al. [Phys. Rev. E 62, 6071 (2000)] by
means of detailed Monte Carlo simulations in one and two dimensions. Particles
of type A may independently hop to an adjacent lattice site provided it is
occupied by at least one B particle. The B particle species undergoes
diffusion-limited reactions. In an active state with nonzero, essentially
homogeneous B particle saturation density, the A species displays normal
diffusion. In an inactive, absorbing phase with exponentially decaying B
density, the A particles become localized. In situations with algebraic decay
rho_B(t) ~ t^{-alpha_B}, as occuring either at a non-equilibrium continuous
phase transition separating active and absorbing states, or in a power-law
inactive phase, the A particles propagate subdiffusively with mean-square
displacement ~ t^{1-alpha_A}. We find that within the accuracy of
our simulation data, \alpha_A = \alpha_B as predicted by a simple mean-field
approach. This remains true even in the presence of strong spatio-temporal
fluctuations of the B density. However, in contrast with the mean-field
results, our data yield a distinctly non-Gaussian A particle displacement
distribution n_A(x,t) that obeys dynamic scaling and looks remarkably similar
for the different processes investigated here. Fluctuations of effective
diffusion rates cause a marked enhancement of n_A(x,t) at low displacements
|x|, indicating a considerable fraction of practically localized A particles,
as well as at large traversed distances.Comment: Revtex, 19 pages, 27 eps figures include

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