Abstract

Motivated by the search for rational points in moduli spaces of two-dimensional conformal field theories, we investigate how points with enhanced symmetry algebras are distributed there. We first study the bosonic sigma-model with S1 target space in detail and uncover hitherto unknown features. We find for instance that the vanishing of the twist gap, though true for the S1 example, does not automatically follow from enhanced symmetry points being dense in the moduli space. We then explore the supersymmetric sigma-model on K3 by perturbing away from the torus orbifold locus. Though we do not reach a definite conclusion on the distribution of enhanced symmetry points in the K3 moduli space, we make several observations on how chiral currents can emerge and disappear under conformal perturbation theory.

Highlights

  • Two classes of 2d CFTs with moduli spaces are known in the literature: 1. CFTs with a u(1) global symmetry, where the exactly marginal operator is the JJoperator

  • Motivated by the search for rational points in moduli spaces of two-dimensional conformal field theories, we investigate how points with enhanced symmetry algebras are distributed there

  • We find for instance that the vanishing of the twist gap, though true for the S1 example, does not automatically follow from enhanced symmetry points being dense in the moduli space

Read more

Summary

Warm-up

We will use a convention where R = 1 corresponds to the self-dual point (the SU(2) WZW model), d2z is normalized so that the integral over the worldsheet torus gives τ2, and the free boson φ is periodic as φ ≡ φ + 2π. With these conventions, the action is given by. Let us consider how the twist changes when perturbing by the exactly marginal operator ∂φ∂ ̄φ, S(λ) = S + λ d2z∂φ∂ ̄φ. For the free boson on S1, we have a closed form expression for the perturbation series, which we can use as a toy model for questions about the density of rational points

Density of rational points
Twist gap
Twist gap from perturbation theory
Basics of perturbation theory
Conformal perturbation theory: shift of conformal dimension
Perturbation theory up to second order
Weight shift near resonances
Four-point function
Weight shift of scalar fields
Weight shift of spin 1 fields
Lifting chiral fields
General resonances
Full Text
Published version (Free)

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call