Supergravity Approach to Tachyon Potential in Brane-Antibrane Systems

Abstract

Using an exact supergravity solution representing the D p −D p system, it is demonstrated that one can construct a supergravity analogue of the tachyon potential. Remarkably, the (regularized) minimum value of the potential turns out to be V (T 0 ) = −2m with m denoting the ADM mass of a single D p -brane. This result, in a sense, appears to confirm that Sen's conjecture for the tachyon condensation on unstable Dbranes is indeed correct although the analysis used here is semi-classical in nature and hence should be taken with some care. Also shown is the fact that the tachyon mass squared m 2 T (which has started out as being negative) can actually become positive definite and large as the tachyon rolls down toward the minimum of its potential. It indeed signals the possibility of successful condensation of the tachyon since it shows that near the minimum of its potential, tachyon can become heavy enough to disappear from the massless spectrum. Some cosmological implications of this tachyon potential in the context of "rolling tachyons" is also discussed.

Inflation from a tachyon fluid?

“…This is phenomenologically the simplest solution, but is at odds with expectations from string theory. (See however [12]. )…”

Hamilton-Jacobi formalism for tachyon inflation

“…The tachyon field associated with unstable D-branes might be responsible for cosmological inflation at early epochs due to tachyon condensation near the top of the effective potential [14,15] and could contribute to some new form of cosmological dark matter at late times [13]. The cosmological aspect of tachyons has been studied by several authors [14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32]. Besides the string theory aspect of this model, tachyon inflation has been considered by utilizing potentials which are related to the k -inflation model [33][34][35].…”

Fubini instantons in curved space

“…If the curvature radius of the potential in the vicinity of the maximum is greater than that used in the above theory, then that will be all together different story. The supergravity analogue of the tachyonic potential could be constructed also by using an exact supergravity solution representing the D p -D p system [16].…”