Optimal Policy Intervention and the Social Value of Public Information

Svensson (2006) argues that Morris and Shin (2002) is, contrary to what is claimed, pro-transparency. This paper reexamines the issue but with an important modification to the original Morris and Shin framework. Recognizing that central banks impact the economy not only indirectly via public announcements, but also directly through policy actions, we consider the social value of public information in the presence of active policy intervention. Our results strengthen Morris and Shin's conclusions considerably: in particular, we find that public disclosure of the central bank's information is unambiguously, i.e., regardless of parameter values, undesirable. (JEL D82, D83, E52, E58)

Higher derivative corrections to R-charged AdS_5 black holes and field redefinitions

We consider four-derivative corrections to the bosonic sector of five-dimensional N=2 gauged supergravity. Since this theory includes the N=2 graviphoton, we consider both curvature and graviphoton field-strength terms that show up at the four-derivative level. We construct, to linear order, the higher-derivative corrections to the non-rotating R-charged AdS_5 black hole and demonstrate how this solution transforms under field redefinitions.Comment: 20 pages, references adde

Variations of Hodge Structure Considered as an Exterior Differential System: Old and New Results

This paper is a survey of the subject of variations of Hodge structure (VHS) considered as exterior differential systems (EDS). We review developments over the last twenty-six years, with an emphasis on some key examples. In the penultimate section we present some new results on the characteristic cohomology of a homogeneous Pfaffian system. In the last section we discuss how the integrability conditions of an EDS affect the expected dimension of an integral submanifold. The paper ends with some speculation on EDS and Hodge conjecture for Calabi-Yau manifolds

Supersymmetric massive truncations of IIb supergravity on Sasaki-Einstein manifolds

Motivated by recent interest in applications of the AdS/CFT correspondence to condensed matter applications involving fermions, we present the supersymmetric completion of the recent massive truncations of IIB supergravity on Sasaki-Einstein manifolds. In particular, we reduce the fermionic sector of IIB supergravity to obtain five dimensional N=2 supergravity coupled to one hypermultiplet and one massive vector multiplet. The supersymmetry transformations and equations of motion are presented and analyzed. Finally, a particularly interesting truncation to N=2 supergravity coupled to a single hypermultiplet is presented which is the supersymmetric completion of the recently constructed bosonic theory dual to a 3+1 dimensional system exhibiting a superconducting phase transition.Comment: v2:reference added, equations simplified, minor typos fixed; v3:matches content with prd version, minor typos correcte

1/N^2 corrections to the holographic Weyl anomaly

We compute the O(1) contribution to holographic c-a for IIB supergravity on AdS_5 x S^5/Z_n and on AdS_5 x T^{1,1}/Z_n. In both cases, we find agreement with the dual field theory results, thus providing 1/N^2 checks of AdS/CFT with reduced supersymmetry. Since the holographic computation involves a sum over shortened multiplets in the KK tower, we provide some details on the S^5 and T^{1,1} spectra in a form that is convenient when considering their Z_n orbifolds. The computation for the even Z_n orbifolds of S^5 includes a sum over the multiplets in the twisted sector that is essential for obtaining agreement with the dual field theory.Comment: 23 pages, 2 figures. v2: minor corrections and references adde

Development and applications of optical interferometric micrometrology in the angstrom and subangstrom range

The recent development of the scanning electron tunneling microscope and the atomic force microscope requires absolute standards for measurements in the angstrom and subangstrom range. Optical interferometry with lasers and multiple mode laser resonances can provide absolute measurements as the laser wavelengths are very accurately known. A key feature of such measurements is the use of piezoelectric crystals as translators of the highest accuracy for very small disturbances. However, the dimensional changes of these crystals resulting from electrical potential changes depend on many variables, among them the method of mounting, so that accurate calibrations are necessary. Starting from advances in optical metrology made by physicists trying to find gravity waves, advances which led to measurements down to 10 to the -5 A, the author designed and built a much simpler system for the angstrom range. The major limiting factors were mechanical vibrations, air currents, thermal changes and laser instabilities

Central charges from the N=1\mathcal{N} = 1 superconformal index

We present prescriptions for obtaining the central charges, $a$ and $c$, of a four dimensional superconformal quantum field theory from the superconformal index. At infinite $N$, for holographic theories dual to Sasaki-Einstein 5-manifolds the prescriptions give the $\mathcal{O}(1)$ parts of the central charges. This allows us, among other things, to show the exact AdS/CFT matching of $a$ and $c$ for arbitrary toric quiver CFTs without adjoint matter that are dual to smooth Sasaki-Einstein 5-manifolds. In addition, we include evidence from non-holographic theories for the applicability of these results outside of a holographic setting and away from the large-$N$ limit.Comment: 4+1 pages. v2: minor revisions and added acknowledgements. v3: improved presentatio

c−ac-a from the N=1N=1 superconformal index

We present a prescription for obtaining the difference of the central charges, c-a, of a four dimensional superconformal quantum field theory from its single-trace index. The formula is derived from a one-loop holographic computation, but is expected to be valid independent of holography. We demonstrate the prescription with several holographic and non-holographic examples. As an application of our formula, we show the AdS/CFT matching of c-a for arbitrary toric quiver CFTs without adjoint matter that are dual to smooth Sasaki-Einstein 5-manifolds.Comment: 19 pages. v2: minor changes, reference added. v3: minor clarifications, published version. v4: a typo in Table 2 fixe