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arXiv · hep-th/0305159

D-brane Decay in Two-Dimensional String Theory

Igor R. Klebanov·Juan Maldacena·Nathan Seiberg
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Abstract

We consider unstable D0-branes of two dimensional string theory, described by the boundary state of Zamolodchikov and Zamolodchikov [hep-th/0101152] multiplied by the Neumann boundary state for the time coordinate $t$. In the dual description in terms of the $c=1$ matrix model, this D0-brane is described by a matrix eigenvalue on top of the upside down harmonic oscillator potential. As suggested by McGreevy and Verlinde [hep-th/0304224], an eigenvalue rolling down the potential describes D-brane decay. As the eigenvalue moves down the potential to the asymptotic region it can be described as a free relativistic fermion. Bosonizing this fermion we get a description of the state in terms of a coherent state of the tachyon field in the asymptotic region, up to a non-local linear field redefinition by an energy-dependent phase. This coherent state agrees with the exponential of the closed string one-point function on a disk with Sen's marginal boundary interaction for $t$ which describes D0-brane decay.

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Igor R. Klebanov, Juan Maldacena, Nathan Seiberg. 2003-06-10. D-brane Decay in Two-Dimensional String Theory. https://doi.org/10.1088/1126-6708%2F2003%2F07%2F045

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