Deformation of the Planetary Orbits Caused by the Time Dependent Gravitational Potential in the Universe

In the paper are studied the deformations of the planetary orbits caused by the time dependent gravitational potential in the universe. It is shown that the orbits are not axially symmetric and the time dependent potential does not cause perihelion precession. It is found a simple formula for the change of the orbit period caused by the time dependent gravitational potential and it is tested for two binary pulsars.Comment: 7 page

Cationic agent contrast-enhanced computed tomography imaging of cartilage correlates with the compressive modulus and coefficient of friction

SummaryObjectiveThe aim of this study is to evaluate whether contrast-enhanced computed tomography (CECT) attenuation, using a cationic contrast agent (CA4+), correlates with the equilibrium compressive modulus (E) and coefficient of friction (μ) of ex vivo bovine articular cartilage.MethodsCorrelations between CECT attenuation and E (Group 1, n = 12) and μ (Group 2, n = 10) were determined using 7 mm diameter bovine osteochondral plugs from the stifle joints of six freshly slaughtered, skeletally mature cows. The equilibrium compressive modulus was measured using a four-step, unconfined, compressive stress-relaxation test, and the coefficients of friction were determined from a torsional friction test. Following mechanical testing, samples were immersed in CA4+, imaged using μCT, rinsed, and analyzed for glycosaminoglycan (GAG) content using the 1,9-dimethylmethylene blue (DMMB) assay.ResultsThe CECT attenuation was positively correlated with the GAG content of bovine cartilage (R2 = 0.87, P < 0.0001 for Group 1 and R2 = 0.74, P = 0.001 for Group 2). Strong and significant positive correlations were observed between E and GAG content (R2 = 0.90, P < 0.0001) as well as CECT attenuation and E (R2 = 0.90, P < 0.0001). The CECT attenuation was negatively correlated with the three coefficients of friction: CECT vs μstatic (R2 = 0.71, P = 0.002), CECT vs μstatic_equilibrium (R2 = 0.79, P < 0.001), and CECT vs μkinetic (R2 = 0.69, P = 0.003).ConclusionsCECT with CA4+ is a useful tool for determining the mechanical properties of ex vivo cartilage tissue as the attenuation significantly correlates with the compressive modulus and coefficient of friction

Holographic Coulomb branch vevs

We compute holographically the vevs of all chiral primary operators for supergravity solutions corresponding to the Coulomb branch of N=4 SYM and find exact agreement with the corresponding field theory computation. Using the dictionary between 10d geometries and field theory developed to extract these vevs, we propose a gravity dual of a half supersymmetric deformation of N=4 SYM by certain irrelevant operators.Comment: 16 pages, v2 corrections in appendi

A Field-theoretical Interpretation of the Holographic Renormalization Group

A quantum-field theoretical interpretation is given to the holographic RG equation by relating it to a field-theoretical local RG equation which determines how Weyl invariance is broken in a quantized field theory. Using this approach we determine the relation between the holographic C theorem and the C theorem in two-dimensional quantum field theory which relies on the Zamolodchikov metric. Similarly we discuss how in four dimensions the holographic C function is related to a conjectured field-theoretical C function. The scheme dependence of the holographic RG due to the possible presence of finite local counterterms is discussed in detail, as well as its implications for the holographic C function. We also discuss issues special to the situation when mass deformations are present. Furthermore we suggest that the holographic RG equation may also be obtained from a bulk diffeomorphism which reduces to a Weyl transformation on the boundary.Comment: 24 pages, LaTeX, no figures; references added, typos corrected, paragraph added to section

Reissner-Nordstrom-de Sitter black hole, planar coordinates and dS/CFT

We discuss the Reissner-Nordstrom-de Sitter black holes in the context of dS/CFT correspondence by using static and planar coordinates. The boundary stress tensor and the mass of the solutions are computed. Also, we investigate how the RG flow is changed for different foliations. The Kastor-Traschen multi-black hole solution is considered as well as AdS counterparts of these configurations. In particular, we find that in planar coordinates the black holes appear like punctures in the dual boundary theory.Comment: 30 pages, 3 eps figures, JHEP style v2: new references added, misprints correcte

Holographic Correlators in a Flow to a Fixed Point

Using holographic renormalization, we study correlation functions throughout a renormalization group flow between two-dimensional superconformal field theories. The ultraviolet theory is an N=(4,4) CFT which can be thought of as a symmetric product of U(2) super WZW models. It is perturbed by a relevant operator which preserves one-quarter supersymmetry and drives the theory to an infrared fixed point. We compute correlators of the stress-energy tensor and of the relevant operators dual to supergravity scalars. Using the former, we put together Zamolodchikov's C function, and contrast it with proposals for a holographic C function. In passing, we address and resolve two puzzles also found in the case of five-dimensional bulk supergravity.Comment: LaTeX2e, 48 pages, 4 figure

Precision Measurement of PArity Violation in Polarized Cold Neutron Capture on the Proton: the NPDGamma Experiment

The NPDGamma experiment at the Los Alamos Neutron Science Center (LANSCE) is dedicated to measure with high precision the parity violating asymmetry in the $\gamma$ emission after capture of spin polarized cold neutrons in para-hydrogen. The measurement will determine unambiguously the weak pion-nucleon-nucleon ($\pi NN$) coupling constant {\it f$^1_{\pi}$}Comment: Proceedings of the PANIC'05 Conference, Santa Fe, NM, USA, October 24-28, 2005, 3 pages, 2 figure

Holographic Renormalization of Foliation Preserving Gravity and Trace Anomaly

From the holographic renormalizationg group viewpoint, while the scale transformation plays a primary role in the duality by providing the extra dimension, the special conformal transformation seems to only play a secondary role. We, however, claim that the space-time diffeomorphism is crucially related to the latter. For its demonstration, we study the holographic renormalization group flow of a foliation preserving diffeomophic theory of gravity (a.k.a. space-time flipped Horava gravity). We find that the dual field theory, if any, is only scale invariant but not conformal invariant. In particular, we show that the holographic trace anomaly in four-dimension predicts the Ricci scalar squared term that would be incompatible with the Wess-Zumino consistency condition if it were conformal. This illustrates how the foliation preserving diffeomophic theory of gravity could be inconsistent with a theorem of the dual unitary quantum field theory.Comment: 18 pages, v2: reference added, v3: comments on more recent literature added in response to referee's reques

Excluded Volume Effects in the Quark Meson Coupling Model

Excluded volume effects are incorporated in the quark meson coupling model to take into account in a phenomenological way the hard core repulsion of the nuclear force. The formalism employed is thermodynamically consistent and does not violate causality. The effects of the excluded volume on in-medium nucleon properties and the nuclear matter equation of state are investigated as a function of the size of the hard core. It is found that in-medium nucleon properties are not altered significantly by the excluded volume, even for large hard core radii, and the equation of state becomes stiffer as the size of the hard core increases.Comment: 14 pages, revtex, 6 figure

Null Deformed Domain Wall

We study null 1/4 BPS deformations of flat domain wall solutions (NDDW) in N=2, d=5 gauged supergravity with hypermultiplets and vector multiplets coupled. These are uncharged time-dependent configurations and contain as special case, 1/2 supersymmetric flat domain walls (DW), as well as 1/2 BPS null solutions of the ungauged supergravity. Combining our analysis with the classification method initiated by Gauntlett et al., we prove that all the possible deformations of the DW have origin in the hypermultiplet sector or/and are null. Here, we classify all the null deformations: we show that they naturally organize themselves into "gauging" (v-deformation) and "non gauging" (u-deformation). They have different properties: only in presence of v-deformation is the solution supported by a time-dependent scalar potential. Furthermore we show that the number of possible deformations equals the number of matter multiplets coupled. We discuss the general procedure for constructing explicit solutions, stressing the crucial role taken by the integrability conditions of the scalars as spacetime functions. Two analytical solutions are presented. Finally, we comment on the holographic applications of the NDDW, in relation to the recently proposed time-dependent AdS/CFT.Comment: 38 pages; minor changes, references added; text revised, minor changes, final version published in JHE