We present a worldvolume effective action suitable for the study of the confined phase of a Dp-anti-Dp system at weak coupling. We identify the mechanism by which the fundamental string arises from this action as a confined electric flux string when the Dp and the anti-Dp annihilate. We construct an explicit dual action, more suitable for the study of the strong coupling regime, and show that it realizes a generalized Higgs-Stueckelberg phase for the (relative) (p-2)-form field dual to the (overall) BI vector. This is the mechanism put forward by Yi and collaborators based on duality arguments in order to explain the breaking of the overall U(1) gauge group at strong coupling. Indeed, in our dual description the Goldstone boson is a (p-3)-form magnetically charged with respect to the overall BI vector field. This indicates that the condensing tachyonic objects originate from open D(p-2)-branes stretched between the brane and the anti-brane. Our results provide an explicit realization of the breaking of the overall U(1) gauge group perturbatively, in a way consistent with the duality symmetries of String Theory.
We consider tachyon condensation between a D-brane and an anti-D-brane in superstring theory, when they are separated in their common transverse directions. A simple rolling tachyon solution, that describes the time evolution of the process, is studied from the point of view of boundary conformal field theory. By computing the boundary beta-functions of the system, one finds that this theory is conformal, hence corresponds to an exact solution of the string theory equations of motion. By contrast, the time-reversal-symmetric rolling tachyon is not conformal. These results put constraints on th…
In superstring theory of type II, the separated brane-antibrane pair admits a bi-fundamental tachyon in its open string spectrum, for any separation less than the critical distance. The dynamics of this system would be described by the Garousi's effective action for any non-zero separation. Our study shows however that the domain of validity of this action only includes space-like tachyon condensation. Previous studies led by Bagchi and Sen showed that, in a partial sub-critical domain, exists a conformal field theory (CFT), which describes a dynamical condensation at static distance, called r…
Antibranes provide some of the most generic ways to uplift Anti-de Sitter flux compactifications to de Sitter, and there is a growing body of evidence that antibranes placed in long warped throats such as the Klebanov-Strassler warped deformed conifold solution have a brane-brane-repelling tachyon. This tachyon was first found in the regime of parameters in which the backreaction of the antibranes is large, and its existence was inferred from a highly nontrivial cancellation of certain terms in the inter-brane potential. We use a brane effective action approach, similar to that proposed by Mic…
Perturbations and moduli space dynamics of tachyon kinks
不稳定D膜衰减为低一维稳定D膜的动力学过程可以用具有Dirac Born Infeld有效作用量的快子场来描述。在本文中，我们研究了快子场的波动模式周围的两个参数的家庭的静态解决方案表示一个数组的膜-反膜对。除了一对零模式与参数的解决方案，和不稳定性与湮灭的膜-反膜对，我们发现相应的状态的激发快子场周围的膜和散装。在膜厚度趋于零的极限下，本征模的支持仅限于膜，这与当快子场接近其基态时传播的快子模从谱中消失的想法一致。在此极限下，包括零模在内的低位激发态表现出4倍简并。最后，我们还讨论了对应于模空间中衰变过程的解的慢运动，找到了一条在不稳定D-膜和低一维的膜-反膜对之间周期振荡的轨迹.
We develop the point of view that brane actions should be understood in the context of effective field theory, and that this is the correct way to treat classical as well as loop divergences. We illustrate this idea in a simple model. We then consider the implications for the dynamics of antibranes in flux backgrounds, focusing on the simplest case of a single antibrane. We argue that there is no tachyonic instability at zero temperature, but there is a nonperturbative process in which an antibrane annihilates with its screening cloud. This is distinct from the NS5-brane instanton decay. Const…
Boundary State Description of Tachyon Condensation
我们构造了膜-反膜系统中涡旋型（余维2）快子凝聚的显式边界态描述，推广了已知的扭结型结果（Frau et al. hep-th/9903123）.在这个描述中，我们展示了低维D-膜的RR-荷是如何出现的。我们还研究了T^4/Z_2轨道中的快子凝聚，发现从边界态的观点来看，扭曲区几乎可以用与非扭曲区相同的方法来处理。进一步讨论了高余维情形。
We study the dynamics of parallel brane-brane and brane-antibrane scattering in string theory in flat spacetime, focusing on the pair production of open strings that stretch between the branes. We are particularly interested in the case of scattering at small impact parameter $b < l_s$, where there is a tachyon in the spectrum when a brane and an antibrane approach within a string length. Our conclusion is that despite the tachyon, branes and antibranes can pass through each other with only a very small probability of annihilating, so long as $g_s$ is small and the relative velocity $v$ is nei…
We construct a new, simple phenomenological model along the lines of AdS/QCD. The essential new ingredient is the brane-antibrane effective action including the open string tachyon proposed by Sen. Chiral symmetry breaking happens because of tachyon dynamics. We fit a large number of low-spin meson masses at the 10%-15% level. The only free parameters involved in the fits correspond to the overall QCD-scale and the quark masses. Several aspects of previous models are qualitatively improved.
