  We theoretically study the vortex formation from the collision of the domain
walls in phase-separated two-component Bose-Einstein condensates. The collision
process mimics the tachyon condensation for the annihilation of D-brane and
anti-D-brane in string theory. A pair annihilation leaves the quantized
vortices with superflow along their core, namely `superflowing cosmic strings'.
It is revealed that the line density and the core size of the vortices depend
on the initial distance between the walls.

Quantum Gases;High Energy Physics - Phenomenology;High Energy Physics - Theory