Giant Gravitons - with Strings Attached (III)

We develop techniques to compute the one-loop anomalous dimensions of operators in the ${\cal N}=4$ super Yang-Mills theory that are dual to open strings ending on boundstates of sphere giant gravitons. Our results, which are applicable to excitations involving an arbitrary number of open strings, generalize the single string results of hep-th/0701067. The open strings we consider carry angular momentum on an S$^3$ embedded in the S$^5$ of the AdS$_5\times$S$^5$ background. The problem of computing the one loop anomalous dimensions is replaced with the problem of diagonalizing an interacting Cuntz oscillator Hamiltonian. Our Cuntz oscillator dynamics illustrates how the Chan-Paton factors for open strings propagating on multiple branes can arise dynamically.Comment: 66 pages; v2: improved presentatio

Complex Matrix Model and Fermion Phase Space for Bubbling AdS Geometries

We study a relation between droplet configurations in the bubbling AdS geometries and a complex matrix model that describes the dynamics of a class of chiral primary operators in dual N=4 super Yang Mills (SYM). We show rigorously that a singlet holomorphic sector of the complex matrix model is equivalent to a holomorphic part of two-dimensional free fermions, and establish an exact correspondence between the singlet holomorphic sector of the complex matrix model and one-dimensional free fermions. Based on this correspondence, we find a relation of the singlet holomorphic operators of the complex matrix model to the Wigner phase space distribution. By using this relation and the AdS/CFT duality, we give a further evidence that the droplets in the bubbling AdS geometries are identified with those in the phase space of the one-dimensional fermions. We also show that the above correspondence actually maps the operators of N=4 SYM corresponding to the (dual) giant gravitons to the droplet configurations proposed in the literature.Comment: 27 pages, 6 figures, some clarification, typos corrected, published versio

Degradação de compostos fenólicos por estirpes de Lactobacillus isoladas de águas russas

Comunicação apresentada no III Simpósio Nacional de Olvicultura que decorreu em Castelo Branco, na Escola Superior Agrária do Instituto Politécnico de Castelo Branco, de 289 a 31 de Outubro de 2003.As águas russas, principal resíduo da indústria de extracção do azeite, são caracterizadas por uma elevada carga orgânica poluente constituindo, por esta razão, um dos mais graves problemas ambientais dos países da bacia mediterrânea. São particularmente ricas em compostos fenólicos, lípidos e açúcares e apresentam teores mínimos de compostos azotados. O seu potencial biológico e energético é importante, pelo que se estudou a possibilidade de serem usadas como meio de cultura para produção de inóculos lácticos para a indústria de preparação de azeitona de mesa. Foram estudadas várias fontes de compensação de azoto, bem como vários tipos de meio, líquido ou sistema bifásico, com vista à maximização da capacidade de degradação de compostos fenólicos por bactérias lácticas (BL). Foram também estudados alguns dos factores de adaptação das BL às condições de stress fenólico. Concluiu-se que a degradação dos compostos fenólicos e a produção de ácido láctico depende do tipo e da concentração de azoto. Verificou-se que as BL possuem um mecanismo de adaptação ao stress fenólico, baseado em alterações dos seus componentes celulares

Electrified BPS Giants: BPS configurations on Giant Gravitons with Static Electric Field

We consider D3-brane action in the maximally supersymmetric type IIB plane-wave background. Upon fixing the light-cone gauge, we obtain the light-cone Hamiltonian which is manifestly supersymmetric. The 1/2 BPS solutions of this theory (solutions which preserve 16 supercharges) are either of the form of spherical three branes, the giant gravitons, or zero size point like branes. We then construct specific classes of 1/4 BPS solutions of this theory in which static electric field on the brane is turned on. These solutions are deformations about either of the two 1/2 BPS solutions. In particular, we study in some detail 1/4 BPS configurations with electric dipole on the three sphere giant, i.e. BIons on the giant gravitons, which we hence call BIGGons. We also study BPS configurations corresponding to turning on a background uniform constant electric field. As a result of this background electric field the three sphere giant is deformed to squashed sphere, while the zero size point like branes turn into circular or straight fundamental strings in the plane-wave background, with their tension equal to the background electric field.Comment: 32 pages, 1 eps figure; v2: Presentation of derivation of light-cone Hamiltonian improved, Refs adde

Fermions from Half-BPS Supergravity

We discuss collective coordinate quantization of the half-BPS geometries of Lin, Lunin and Maldacena (hep-th/0409174). The LLM geometries are parameterized by a single function $u$ on a plane. We treat this function as a collective coordinate. We arrive at the collective coordinate action as well as path integral measure by considering D3 branes in an arbitrary LLM geometry. The resulting functional integral is shown, using known methods (hep-th/9309028), to be the classical limit of a functional integral for free fermions in a harmonic oscillator. The function $u$ gets identified with the classical limit of the Wigner phase space distribution of the fermion theory which satisfies u * u = u. The calculation shows how configuration space of supergravity becomes a phase space (hence noncommutative) in the half-BPS sector. Our method sheds new light on counting supersymmetric configurations in supergravity.Comment: 28 pages, 2 figures, epsf;(v3) eq. (3.3) clarified and notationally simplified; version to appear in JHE

Проблематика переходу до інформаційного суспільства

Аналізуються фундаментальні передумови, що є первинними в процесі творення інформаційного суспільства. Обґрунтовується теза, що електронна готовність та електронне залучення є основоположними факторами переходу суспільства від індустріального до інформаційного устрою. Подано основні характеристики цих понять та наголошено на їх значенні

Half-BPS Giants, Free Fermions and Microstates of Superstars

We consider 1/2-BPS states in AdS/CFT. Using the matrix model description of chiral primaries explicit mappings among configurations of fermions, giant gravitons and the dual-giant gravitons are obtained. These maps lead to a `duality' between the giant and the dual-giant configurations which is the reflection of particle-hole duality of the fermion picture. These dualities give rise to some interesting consequences which we study. We then calculate the degeneracy of 1/2-BPS states both from the CFT and string theory and show that they match. The asymptotic degeneracy grows exponentially with the comformal dimension. We propose that the five-dimensional single charge `superstar' geometry should carry this density of states. An appropriate stretched horizon can be placed in this geometry and the entropy predicted by the CFT and the string theory microstate counting can be reproduced by the Bekenstein-Hawking formula up to a numerical coefficient. Similar M-theory examples are also considered.Comment: 21 pages, v2:typos corrected and references adde

Giants On Deformed Backgrounds

We study giant graviton probes in the framework of the three--parameter deformation of the AdS_5 x S^5 background. We examine both the case when the brane expands in the deformed part of the geometry and the case when it blows up into AdS. Performing a detailed analysis of small fluctuations around the giants, the configurations turn out to be stable. Our results hold even for the supersymmetric Lunin-Maldacena deformation.Comment: LaTex, 28 pages, uses JHEP3; v2: minor corrections, references added; v3: final version accepted for publication in JHE