AdS bubbles, entropy and closed string tachyons

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.

Entanglement entropy, trace anomalies and holography

“…6) we conclude that the holographic type A Weyl anomaly in d = 2n dimensions is a n E 2n with a n as in (A.1).…”

“…There it was observed that while the type B Weyl anomalies have a trivial descent, the unique (in any even dimensions) type A anomaly has a non-trivial descent. 6 These features might, in fact, serve as the defining distinction between the two classes of anomalies, which can also be applied to the hypersurface anomalies discussed in Section 3.…”

“…Arguments for the validity of this assumption were presented in [4]. Using the aforementioned holographic representation for massive d = 4 theories in [5] information about the phase structure of these theories was obtained; see also [6] for an earlier discussion of this issue.…”

Non-equilibrium condensation process in holographic superconductor with nonlinear electrodynamics

“…The entanglement entropy is considered as an effective measure of how a given quantum system is strongly correlated. It has been proven as a powerful tool to describe different phases and the corresponding phase transitions in holographic superconductors [86]- [98]. In this section, we will calculate the holographic entangle entropy in the non-equilibrium process and further disclose that the entanglement entropy can be regarded as a useful tool in describing the holographic superconductor.…”

“…The entanglement entropy is directly related to the degrees of freedom of a system to keep track of them. From [86,99,100], we can see in a time-dependent background the entanglement entropy associated with a specified region on the boundary in the context of the AdS/CFT correspondence is given by the area of a co-dimension two bulk surface with vanishing expansions of null geodesics. We will follow this treatment to calculate the entanglement entropy in the time-dependent background.…”