Covariant Calculus for Effective String Theories

Understand

A covariant calculus for the construction of effective string theories is developed.

• Effective string theory, describing quantum string-like excitations in arbitrary dimension, has in the past been constructed using the principles of conformal field theory, but not in a systematic way.
• Using the freedom of choice of field definition, a particular field definition is made in a systematic way to allow an explicit construction of effective string theories with manifest exact conformal symmetry.
• The impossibility of a manifestly invariant description of the Polchinski-Strominger Lagrangian is demonstrated and its meaning is explained.