D-brane decay in two-dimensional string theory

Abstract

We consider unstable D0-branes of two dimensional string theory, described by the boundary state of Zamolodchikov and Zamolodchikov [36] 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 [25], 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.

Two-dimensional superstrings and the supersymmetric matrix model

“…This proposal reinterprets the matrix-model/string-theory correspondence as a holographic open-string/closed-string duality, and suggests a search algorithm for more examples. It has been clarified [3,4,5,6] and very recently extended to type 0 strings [7,8]. In this note, we apply this perspective to shed some new light on the physical identification of the supersymmetric matrix model of Marinari and Parisi [9].…”

“…Following the logic of [1,3] we start by examining the open string spectrum of the unstable D-particles.…”

“…It should be possible to generalize the analysis of [1,3,4] to study the decay of a single unstable D-brane. This will presumably involve a superfield version of the fermion operator that creates and destroys the super-eigenvalues, and a superfield bosonization formula along the lines of [48].…”

Collective Field Description of Matrix Cosmologies

“…Note that the coordinates are smooth across the steep/shallow divide. 1 As an aside, consider a modification to the droplet discussed above. At time t = 0, replace the regions π/4 < θ < 3π/4 and 5π/4 < θ < 7π/4 by straight lines so that the droplet takes the form of a rectangle with semi-circular ends.…”

Time-dependent backgrounds of 2D string theory: Non-perturbative effects

“…Recent works [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21] suggested to think of the matrix models as dual open string theories in presence of D-branes and led to an interpretation of the non-perturbative phenomena in terms of open string world sheets with appropriate boundary conditions. This interpretation was prepared, from the string theory side, by the remarkable works on Liouville CFT with boundary, which has been solved using conformal bootstrap methods [22][23][24][25][26].…”