Stability of D1-Strings Inside a D3-Brane

Abstract

Within the tachyon condensation approach, we find that a D(p-2)-brane is stable inside Dp-branes when the bulk is compactified. It is a codimension-2 soliton of the Dp-brane action with coupling to the bulk (p-1)-form RR field. We discuss the properties of such solitons. They may appear as detectable cosmic strings in our universe.

Figures (4)

• Figure 1: $A_{\theta}$ (solid line), $d\phi$ (dashed line) and $\star dC_2$ (dot-dashed line), where we have set $a=\xi=n=1$. $d\phi$ is canceled by $A_1$ to screen the RR charge, so $\star dC_2$ drops exponentially for large $r$.
• Figure 2: The total energy density $\mathcal{E}$ (dashed line) and the energy density in the B field (solid line). Here, $a=n=\xi=1$.
• Figure 3: A D1-string intersecting a D3-brane and forming a D1-vortex inside the D3-brane. The picture also shows a D1-vortex loop existing on its own.
• Figure 4: The D3-D3-anti-D3 system. The $\text{D} \overline{\text{D}}$-branes on which $T_2$ ends are always on top of each other. Creation of a vortex by first forming the D1-string (from the annihilation of the D3-anti-D3 pair) outside the other D3-brane and then bringing it back. Alternatively, one can form the vortex directly on the D3-brane. Arrows up represent D3-branes and the arrow down represents the anti-D3-brane.