Strings with Negative Stiffness and Hyperfine Structure

TL;DR

This paper introduces a modified string model with higher-order terms allowing for negative stiffness while maintaining stability, revealing new phases and fixed points with implications for string world-sheet geometry.

Contribution

It presents a novel string model incorporating higher-order gradient terms, enabling negative stiffness and discovering new phases and fixed points in the large-D limit.

Findings

Identification of three phases in the model

Discovery of a fixed point with vanishing tension

Suppression of crumpling due to the new term

Abstract

We propose a new string model by adding a higher-order gradient term to the rigid string, so that the stiffness can be positive or negative without loosing stability. In the large-D approximation, the model has three phases, one of which with a new type of generalized "antiferromagnetic" orientational correlations. We find an infrared-stable fixed point describing world-sheets with vanishing tension and Hausdorff dimension D_H=2. Crumpling is prevented by the new term which suppresses configurations with rapidly changing extrinsic curvature.