D-branes in the Lorentzian Melvin Geometry

TL;DR

This paper investigates string theory in the Lorentzian Melvin background, analyzing D-brane spectra and string emission, revealing how certain D-branes emit winding strings due to the modified open string Hamiltonian.

Contribution

It provides a solvable conformal field theory model for time-dependent string dynamics and explores the emission of winding strings from D-branes in this background.

Findings

Wrapping D2-branes emit winding strings.

Codimension-one D-strings emit winding strings.

Modified open string Hamiltonian explains emission behavior.

Abstract

We consider string theory on the Lorentzian Melvin geometry, which is obtained by analytically continuing the two-parameter Euclidean Melvin background. Because this model provides a solvable conformal field theory that describes time-dependent twisted string dynamics, we study the string one-loop partition function and the D-brane spectrum. We found that both the wrapping D2-brane and the codimension-one D-string emit winding strings, and this behavior can be traced to the modified open string Hamiltonian on these probe D-branes.