Question on D=26 --- String Theory versus Quantum Gravity ---

TL;DR

This paper critically reviews derivations of the critical dimension D=26 in bosonic string theory within two-dimensional quantum gravity, clarifying their relations and proposing a unified anomaly explanation.

Contribution

It demonstrates that string theory is a specific aspect of two-dimensional quantum gravity and introduces a new unified approach to understanding anomalies.

Findings

Critical dimension D=26 derived through multiple methods

String theory is a particular case within 2D quantum gravity

Unified explanation for various anomalies in the framework

Abstract

In the covariant-gauge two-dimensional quantum gravity, various derivations of the critical dimension D=26 of the bosonic string are critically reviewed, and their interrelations are clarified. It is shown that the string theory is not identical with the proper framework of the two-dimensional quantum gravity, but the former should be regarded as a particular aspect of the latter. The appearance of various anomalies is shown to be explainable in terms of a new type of anomaly in a unified way.