String Tension and the Generation of the Conformal Anomaly

Abstract

The origin of the string conformal anomaly is studied in detail. We use a reformulated string Lagrangian which allows to consider the string tension $T_0$ as a small perturbation. The expansion parameter is the worldsheet speed of light c, which is proportional to $T_0$ . We examine carefully the interplay between a null (tensionless) string and a tensionful string which includes orders $c^2$ and higher. The conformal algebra generated by the constraints is considered. At the quantum level the normal ordering provides a central charge proportional to $c^2$. Thus it is clear that quantum null strings respect conformal invariance and it is the string tension which generates the conformal anomaly.

More references are included. Final version, to appear in Phys.Rev.D. 6 pages, LaTex, no figures

References in corpus (4)

• Classical and Quantized Tensionless Strings
• Hamiltonian BRST Quantization of the Conformal String
• String Quantization in Curved Spacetimes: Null String Approach
• The Zero Tension Limit of The Virasoro Algebra and the Central Extension

Cited by in corpus (2)

• M Theory Model of a Big Crunch/Big Bang Transition
• Worldsheet Instantons and a Null String Limit of Born-Infeld Theory