arXiv subjects
Publications and source records attributed to Korkut Bardakci.
In this paper, a new approach to string dynamics is proposed. String coordinates are identified with a non-commuting set of operators familiar from free string quantization, and the dynamics follows from the Virasoro algebra. There is a very large gauge group operating on the non-commuting coordinates. The gauge has to be fixed suitably to make contact with the standard string picture.
We improve and extend a method introduced in an earlier paper for deriving string field equations. The idea is to impose conformal invariance on a generalized sigma model, using a background field method that ensures covariance under very general non-local coordinate transformations. The method is used to derive the free string equations, as well as the interacting equations for the graviton-dilaton system. The full interacting string equations derived by this method should be manifestly background independent.
In the large N limit, conditions for the conformal invariance of the generalized Thirring model are derived, using two different approaches: the background field method and the Hamiltonian method based on an operator algebra, and the agreement between them is established. A free field representation of the relevant algebra is presented, and the structure of the stress tensor in terms of free fields (and free currents) is studied in detail.
The conformal fixed points of the generalized Thirring model are investigated with the help of bosonization, the large N limit and the operator product expansion. Necessary conditions on the coupling constants for conformal invariance are derived.
A new string theory is proposed as a candidate for the large N limit of QCD. In this theory, strings are constrained to be non-backtracking; a condition that is essential for the gauge invariance of the underlying field theory.This condition is implemented by first placing the theory on a lattice and then introducing fermionic variables on the world sheet. The naive continuum limit leads to a generalized Thirring model on the world sheet,and it is suggested that the application of the renormalization group should drive the coupling constants to a conformally invariant fixed point.