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It is a well-studied phenomenon in AdS$_3$/CFT$_2$ that pure states often appear 'too thermal' in the classical gravity limit, leading to a version of the information puzzle. One example is the case of a heavy scalar primary state, whose associated classical geometry is the BTZ black hole. Another example is provided by a heavy left-moving primary, which displays late time decay in chiral correlators. In this paper we study a special class of pure state geometries which do not display such information loss. They describe heavy CFT states created by a collection of chiral operators at various positions on the complex plane. In the bulk, these take the form of multi-centered solutions from the backreaction of a collection of spinning particles, which we construct for circular distributions of particles. We compute the two-point function of probe operators in these backgrounds and show that information is retrieved. We observe that the states for which our geometric picture is reliable are highly extended star-like objects in the bulk description. This may point to limitations of the semiclassical fuzzball picture of black hole microstates., Comment: 48 pages, 12 figures, published version

We propose a non-unitary example of holography for the family of two-dimensional logarithmic conformal field theories with negative central charge $c= c_{p,1} = - 6p +13 - 6 p^{-1}$. We argue that at large $p$, these models have a semiclassical gravity-like description which contains, besides the global AdS$_3$ spacetime, a tower of solitonic solutions describing conical excess angles. Evidence comes from the fact that the central charge and the natural modular invariant partition function of such a theory coincide with those of the $c_{p,1}$ model. These theories have an extended chiral W-algebra whose currents have large spin of order $|c|$, and which in the bulk are realized as spinning conical solutions. As a by-product we also find a direct link between geometric actions for exceptional Virasoro coadjoint orbits, which describe fluctuations around the conical spaces, and Felder's free field construction of degenerate representations., 33 pages, 1 figure. V2: references added

Motivated by the question of bulk localization in holography, we study the problem of constructing multi-centered solutions in higher spin gravity which describe point particles in the interior of AdS3. In the Chern-Simons formulation these take into account the backreaction after adding Wilson line sources. We focus on chiral solutions where only the left-moving sector is excited. In that case it is possible to choose a gauge where the dynamical variables are a set of Toda fields living in the bulk. The problem then reduces to solving the $$ {{\mathcal{A}}_N}_{-1} $$ A N − 1 Toda equations with delta function sources, which in turn requires solving an associated monodromy problem. We show that this monodromy problem is equivalent to the monodromy problem for a particular $$ {\mathcal{W}}_N $$ W N vacuum conformal block at large central charge. Therefore, knowledge of the $$ {\mathcal{W}}_N $$ W N vacuum block determines the multi-centered solution. Our calculations go beyond the heavy-light approximation by including the backreaction of all higher spin particles.

Gaberdiel and Gopakumar recently proposed that the tensionless limit of string theory on $AdS_3 \times S^3 \times T^4$ takes the form of a higher spin theory with a gauge algebra that is referred to as the higher spin square. In this note, we formulate the linearized Vasiliev-type equations which describe a matter field coupled to the higher spin square. We study the particle spectrum of this field and show that it accounts for the entire untwisted sector of the dual symmetric orbifold CFT, thereby confirming a conjecture by Gaberdiel and Gopakumar. In doing so, we pinpoint the group-theoretic data which determine the spectrum of a matter field coupled to a general higher spin algebra, which we illustrate by revisiting the theory based on the $hs[1/2]$ algebra., 18 pages. V2: minor changes, reference added

We construct simple solutions of three-dimensional higher spin gravity interacting with matter in which only the scalar and spin-two fields are excited. They preserve Lorentz symmetry and are similar to the four-dimensional solutions constructed by Sezgin and Sundell, with the difference that the additional twisted sectors of the three-dimensional theory are excited. Furthermore, the three-dimensional system contains an extra parameter $\lambda$ which allows us to vary the mass of the scalar. Among other reasons, the resulting solutions are interesting for the holographic study of cosmological singularities: they describe the growth of a Coleman-De Luccia bubble in anti-de Sitter space, ending in a big crunch singularity. We initiate the holographic study of these solutions, finding evidence for their interpretation within a multi-trace deformation which renders the dual field theory unstable. The limit $\lambda \to 0$ is particularly interesting as it captures effects of a running coupling in a large-$N$ interacting fermion model. We also propose a generalization of our solutions, consisting of a dressing with Lorentz-invariant projectors. This additional sector remains non-trivial when the scalar field is turned off., Comment: Truncation to the 3D minimal bosonic model, clarifications and one reference added. Typos corrected. Version accepted for publication in JHEP

We revisit supersymmetric solutions to five dimensional ungauged N=1 supergravity with dynamic hypermultiplets. In particular we focus on a truncation to the axion-dilaton contained in the universal hypermultiplet. The relevant solutions are fibrations over a four-dimensional Kahler base with a holomorphic axion-dilaton. We focus on solutions with additional symmetries and classify Killing vectors which preserve the additional structure imposed by supersymmetry; in particular we extend the existing classification of solutions with a space-like U(1) isometry to the case where the Killing vector is rotational. We elaborate on general geometrical aspects which we illustrate in some simple examples. We especially discuss solutions describing the backreaction of M2-branes, which for example play a role in the black hole deconstruction proposal for microstate geometries., Comment: 48 pages + appendices, 5 figures

We construct a class of smooth solutions in three-dimensional Vasiliev higher spin theories based on the gauge algebra hs[λ]. These solutions naturally generalize the previously constructed conical defect solutions in higher spin theories with sl(N) gauge algebra, to which they reduce when λ is taken to be equal to N. We provide evidence for their identification with specific primary states of the W∞[λ] algebra in a particular classical limit. In terms of the Gaberdiel-Gopakumar-'t Hooft limit of the WN minimal models, this limit corresponds to a regime where the't Hooft coupling becomes large. © 2013 SISSA, Trieste, Italy., SCOPUS: ar.j, info:eu-repo/semantics/published

We construct a family of supersymmetric solutions to AdS supergravity in three dimensions, that correspond to type IIB seven branes wrapped on an internal S3xT4. These solutions are generalizations of the three dimensional Goedel universe and have closed timelike curves. We propose an enhancon-like mechanism for excising the closed timelike curve region by including the effects of additional light degrees of freedom. These take the form of tensionless 7-brane probes, effectively described through the backreaction of a smeared domain wall. The absence of closed timelike curves in the asymptotic AdS3 geometries obtained in this way is shown to be equivalent to a unitarity bound in the dual CFT, known as the stringy exclusion principle., Comment: 42 pages, 4 figures

We show that M-theory admits a supersymmetric compactification to the Godel universe of the form Godel3 x S2 x CY3. We interpret this geometry as coming from the backreaction of M2-branes wrapping the S2 in an AdS3 x S2 x CY3 flux compactification. In the black hole deconstruction proposal similar states give rise to the entropy of a D4-D0 black hole. The system is effectively described by a three-dimensional theory consisting of an axion-dilaton coupled to gravity with a negative cosmological constant. Other embeddings of the three-dimensional theory imply similar supersymmetric Godel compactifications of type IIA/IIB string theory and F-theory., 21 pages+appendices, 3 figures

We present a simple example of a supersymmetric attractor mechanism in the purely open string context of D-branes embedded in curved space-time. Our example involves a class of D3-branes embedded in the 2-charge D1-D5 background of type IIB whose worldvolume contains a 2-sphere. Turning on worldvolume fluxes, these branes carry induced (p,q) string charges. Supersymmetric configurations display a flow of the open string moduli towards an attractor solution independent of their asymptotics. The equations governing this mechanism closely resemble the attractor flow equations for supersymmetric black holes in closed string theory. The BPS equations take the form of a gradient flow and describe worldvolume solitons interpolating between an AdS_2 geometry where the two-sphere has collapsed, and an attractor solution with AdS_2 x S^2 geometry. In these limiting solutions, the preserved supersymmetry is enhanced from 4 to 8 supercharges. We also discuss the interpretation of our solutions as intersecting brane configurations placed in the D1-D5 background, as well as the S-duality transformation to the F1-NS5 background., 37 pages, 6 figures. v2: small corrections, figure and references added

In hep-th/0412322, Gaiotto, Strominger and Yin proposed a novel way of counting black hole microstates by counting the quantum mechanical ground states of probe branes placed in the near-horizon black hole background. We discuss the generalization of this proposal to the case of two-charge D0-D4 `small' black holes in type IIA. We also describe the construction of BPS D-brane probes in the near-horizon region of the 2-charge D1-D5 system in type IIB. Based on hep-th/0505176, hep-th/0607150., 5 pages, contribution to the proceedings of the RTN project `Constituents, Fundamental Forces and Symmetries of the Universe' conference in Napoli, October 9 - 13, 2006

We construct supersymmetric D-brane probe solutions in the background of the 2-charge D1-D5 system on M, where M is either K3 or T^4. We focus on `near-horizon bound states' that preserve supersymmetries of the near-horizon AdS_3 x S^3 x M geometry and are static with respect to the global time coordinate. We find a variety of half-BPS solutions that span an AdS_2 subspace in AdS_3, carry worldvolume flux and can wrap an S^2 within S^3 and/or supersymmetric cycles in M., Latex, 24 pages. v2: references added, modified Discussion, published version

Recently, Gaiotto, Strominger and Yin have proposed a holographic representation of the microstates of certain N=2 black holes as chiral primaries of a superconformal quantum mechanics living on D0-branes in the attractor geometry. We show that their proposal can be succesfully applied to `small' black holes which are dual to Dabholkar-Harvey states and have vanishing horizon area in the leading supergravity approximation. This note is a summary of hep-th/0505176 with S. Kim., 4 pages, to appear in the proceeding of PASCOS 2005, Gyeongju, Korea, May 30-June 4, 2005

We calculate the interaction potential between widely separated D-branes in PP-wave backgrounds in string theory as well as in low-energy supergravity. Timelike and spacelike orientations are qualitatively different but in both cases the effective brane tensions and RR charges take the same values as in Minkowski space in accordance with the expectations from the sigma model perturbation theory., Latex, 22 pages. Typos corrected and a reference added, final version

We study the ghost sector of vacuum string field theory where the BRST operator Q is given by the midpoint insertion proposed by Gaiotto, Rastelli, Sen and Zwiebach. We introduce a convenient basis of half-string modes in terms of which Q takes a particularly simple form. We show that there exists a field redefinition which reduces the ghost sector field equation to a pure projection equation for string fields satisfying the constraint that the ghost number is equally divided over the left- and right halves of the string. When this constraint is imposed, vacuum string field theory can be reformulated as a $U(\infty)$ cubic matrix model. Ghost sector solutions can be constructed from projection operators on half-string Hilbert space just as in the matter sector. We construct the ghost sector equivalent of various well-known matter sector projectors such as the sliver, butterfly and nothing states., 25 pages, no figures. Typos corrected, published version

We discuss the quantization and holographic aspects of a class of conical spaces in 2+1 dimensional pure AdS gravity. These appear as topological solitons in the Chern-Simons formulation of the theory and are closely related to the recently studied conical solutions in higher spin gravity. We discuss the classical fluctuations around these solutions, which form exceptional coadjoint orbits of the asymptotic Virasoro group. We argue that the quantization of these solutions leads to nonunitary representations of the Virasoro algebra, on account of their having boundary graviton fluctuations which lower the energy. We propose a framework to quantize them in a semiclassical expansion in the inverse central charge, which we use to compute their one-loop corrected energies. Interestingly, the resulting Virasoro representations contain a null vector, thus providing an appearance of Kac's degenerate representations, which are nonunitary at large central charge, in the context of gravity. We match the computed quantum corrections in the bulk with the properties of a class of primaries in Kac's classification., Comment: 26 pages. V2: minor changes; references and calculational details added