Inhomogeneous tachyon condensation

Hindmarsh, Mark and Li, Huiquan (2009) Inhomogeneous tachyon condensation. Journal of High Energy Physics (6). ISSN 1029-8479

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We investigate the spacetime-dependent condensation of the tachyon in effective field theories. Previous work identified singularities in the field which appear in finite time: infinite gradients at the kinks, and (in the eikonal approximation) caustics near local minima. By performing a perturbation analysis, and with numerical simulations, we demonstrate and explain key features of the condensation process: perturbations generically freeze, and minima develop singular second derivatives in finite time (caustics). This last feature has previously been understood in terms of the eikonal approximation to the dynamics. We show explicitly from the field equations how this approximation emerges, and how the caustics develop, both in the DBI and BSFT effective actions. We also investigate the equation of state parameter of tachyon matter showing that it is small, but generically non-zero. The energy density tends to infinity near field minima with a charateristic profile. A proposal to regulate infinities by modifying the effective action is also studied. We find that although the infinities at the kinks are successfully regularised in the time-dependent case, caustics still present.

Item Type: Article
Additional Information: Article Number: 050
Schools and Departments: School of Mathematical and Physical Sciences > Physics and Astronomy
Depositing User: Mark Hindmarsh
Date Deposited: 06 Feb 2012 18:39
Last Modified: 07 Mar 2017 09:26

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