AdS Bubbles, Entropy and Closed String Tachyons

TL;DR

This paper explores the relationship between AdS bubbles and closed string tachyon condensation, demonstrating entropy decrease, matching gauge/gravity results, and analyzing time-dependent backgrounds with null boundaries.

Contribution

It provides new insights into the connection between AdS bubbles and tachyon condensation, including entropy behavior and explicit calculations in gauge/gravity duality.

Findings

Entanglement entropy decreases under tachyon condensation.

Gauge and gravity entropies agree remarkably.

Null boundary spacetimes with tachyon walls are constructed.

Abstract

We study the conjectured connection between AdS bubbles (AdS solitons) and closed string tachyon condensations. We confirm that the entanglement entropy, which measures the degree of freedom, decreases under the tachyon condensation. The entropies in supergravity and free Yang-Mills agree with each other remarkably. Next we consider the tachyon condensation on the AdS twisted circle and argue that its endpoint is given by the twisted AdS bubble, defined by the double Wick rotation of rotating black 3-brane solutions. We calculated the Casimir energy and entropy and checked the agreements between the gauge and gravity results. Finally we show an infinite boost of a null linear dilaton theory with a tachyon wall (or bubble), leads to a solvable time-dependent background with a bulk tachyon condensation. This is the simplest example of spacetimes with null boundaries in string theory.