TY - JOUR

T1 - Open string radiation from decaying FZZT branes

AU - Konechny, Anatoly

PY - 2008/8/1

Y1 - 2008/8/1

N2 - In this paper we continue studying the decay of unstable FZZT branes initiated in [1], [2]. The mass of tachyonic mode in this model can be chosen arbitrarily small and we use it as a perturbative parameter. In [2] a time-dependent boundary conformal field theory (BCFT) describing the decay process was studied and it was shown that in a certain sense this BCFT interpolates between two stationary BCFT's corresponding to the UV and IR fixed points of the associated RG flow. In the present work we find in the leading order vertex operators of the time-dependent BCFT. We identify the ''in'' and ''out'' vertex operators assigned to the UV and IR fixed points and compute the related Bogolyubov coefficients. We show that there is a codimension one subspace of the out-going states for which pair creation amplitudes are independent of the initial wave function of the tachyonic mode. We demonstrate that such amplitudes can be computed within the framework of first quantized open string theory via suitably defined string two-point functions. We also evaluate a three point function which we interpret as an amplitude for string triplet creation due to interaction. Some peculiarities of scattering amplitudes in the presence of tachyonic modes in the far past are discussed.

AB - In this paper we continue studying the decay of unstable FZZT branes initiated in [1], [2]. The mass of tachyonic mode in this model can be chosen arbitrarily small and we use it as a perturbative parameter. In [2] a time-dependent boundary conformal field theory (BCFT) describing the decay process was studied and it was shown that in a certain sense this BCFT interpolates between two stationary BCFT's corresponding to the UV and IR fixed points of the associated RG flow. In the present work we find in the leading order vertex operators of the time-dependent BCFT. We identify the ''in'' and ''out'' vertex operators assigned to the UV and IR fixed points and compute the related Bogolyubov coefficients. We show that there is a codimension one subspace of the out-going states for which pair creation amplitudes are independent of the initial wave function of the tachyonic mode. We demonstrate that such amplitudes can be computed within the framework of first quantized open string theory via suitably defined string two-point functions. We also evaluate a three point function which we interpret as an amplitude for string triplet creation due to interaction. Some peculiarities of scattering amplitudes in the presence of tachyonic modes in the far past are discussed.

KW - Conformal field models in string theory

KW - D-branes

KW - Tachyon condensation

UR - http://www.scopus.com/inward/record.url?scp=54749140394&partnerID=8YFLogxK

U2 - 10.1088/1126-6708/2008/08/011

DO - 10.1088/1126-6708/2008/08/011

M3 - Article

SN - 1126-6708

VL - 2008

JO - Journal of High Energy Physics

JF - Journal of High Energy Physics

IS - 8

ER -