Electromagnetic string fluid in rolling tachyon

Abstract

We study Born-Infeld type effective action for unstable D3-brane system including a tachyon and an Abelian gauge field, and find the rolling tachyon with constant electric and magnetic fields as the most general homogeneous solution. Tachyonic vacua are characterized by magnitudes of the electric and magnetic fields and the angle between them. Analysis of small fluctuations in this background shows that the obtained configuration may be interpreted as a fluid consisting of string-like objects carrying electric and magnetic fields. They are stretched along one direction and the rolling tachyon move in a perpendicular direction to the strings. Direction of the propagating waves coincides with that of strings with velocity equal to electric field.

Homogeneous rolling tachyons in boundary string field theory

“…To be specific, they are hyperbolic cosine type rolling tachyon solution for √ β H/α < T p , exponential type rolling tachyon solution for √ β H/α = T p , and hyperbolic sine type rolling tachyon solution for √ β H/α > T p . The obtained spectrum of rolling tachyons in BSFT action coincides with that in BCFT [20], DBI type EFT [20,21,8], and NCFT [20,9]. Even functional form of the tachyon field for the homogeneous rolling tachyons is the same up to the rescaling of the time variable so that we omit detailed analysis of their physical properties.…”

Tachyon kinks

“…Here we use a runaway tachyon potential 2) which is derived from open string theory [24] and was originally introduced in Ref. [9,35,33,34]. In the context of string field theory, form of the action and the potential is different from our choice [23], which is also allowed due to scheme dependence.…”

“…It means that the solutions are classified by two independent parameters, (Π, E) or equivalently (−T 11 , E). In the context of string theory, the existence of the constant background electric field E and its conjugate momentum density Π is interpreted as that of a string fluid consisting of straight F1's along x-axis [7,8,9]. Here we assume positive E, Π, and −T 11 for convenience without loss of generality.…”

Rolling of a modulated tachyon with gauge flux and an emergent fundamental string

“…This is to be contrasted with the situation of homogeneous tachyon rolling, where turning on electric field e induces a fundamental string fluid on the decaying D-brane world-volume, but the fluid is at rest. As shown in [15,16], turning on magnetic field b perpendicular to the electric field lets the fluid to flow rigidly. We now find that modulated tachyon field can also trigger the fundamental string gas to flow.…”