Strings from Tachyons

TL;DR

This paper reinterprets the c=1 matrix model as the world-line theory of unstable D-particles with a non-abelian open string tachyon, establishing a quantitative match with closed string emission and exploring dualities in string theory.

Contribution

It introduces a new interpretation of the c=1 matrix model as D-particle world-line theory and connects it to string theory dualities and decoupling limits.

Findings

Quantitative match between closed string emission and rolling eigenvalues.

Explanation of the double-scaling limit as an equivalence class.

Definition of a decoupling limit linking to the c=1 matrix model.

Abstract

We propose a new interpretation of the c=1 matrix model as the world-line theory of N unstable D-particles, in which the hermitian matrix is provided by the non- abelian open string tachyon. For D-particles in 1+1-d string theory, we find a direct quantitative match between the closed string emission due to a rolling tachyon and that due to a rolling eigenvalue in the matrix model. We explain the origin of the double-scaling limit, and interpret it as an extreme representative of a large equivalence class of dual theories. Finally, we define a concrete decoupling limit of unstable D-particles in IIB string theory that reduces to the c=1 matrix model, suggesting that 1+1-d string theory represents the near-horizon limit of an ultra-dense gas of IIB D-particles.