Is cosmological constant screened in Liouville gravity with matter?

There has been a proposal that infrared quantum effects of massless interacting field theories in de-Sitter space may provide time-dependent screening of the cosmological constant. As a concrete model of the proposal, we study the three loop corrections to the energy-momentum tensor of massless $\lambda \phi^4$ theory in the background of classical Liouville gravity in $D=2$ dimensional de-Sitter space. We find that the cosmological constant is screened in sharp contrast to the massless $\lambda \phi^4$ theory in $D=4$ dimensions due to the sign difference between the cosmological constant of the Liouville gravity and that of the Einstein gravity. To argue for the robustness of our prediction, we introduce the concept of time-dependent infrared counter-terms and examine if they recover the de-Sitter invariance in the $\lambda \phi^4$ theory in comparison with the Sine-Gordon model where it was possible.Comment: 28 pages, 7 eps figure

Towards multi-field D-brane inflation in a warped throat

We study the inflationary dynamics in a model of slow-roll inflation in warped throat. Inflation is realized by the motion of a D-brane along the radial direction of the throat, and at later stages instabilities develop in the angular directions. We closely investigate both the single field potential relevant for the slow-roll phase, and the full multi-field one including the angular modes which becomes important at later stages. We study the main features of the instability process, discussing its possible consequences and identifying the vacua towards which the angular modes are driven.Comment: (v1) 35 pages, 7 figures, 2 tables; (v2) 37 pages, more discussions and references, to appear in Journal of Cosmology and Astroparticle Physic

The c-axis charge traveling wave in coupled system of Josephson junctions

We demonstrate a manifestation of the charge traveling wave along the c-axis (TW) in current voltage characteristics of coupled Josephson junctions in high-$T_c$ superconductors. The branches related to the TW with different wavelengths are found for the stacks with different number of Josephson junctions at different values of system's parameters. Transitions between the TW branches and the outermost branch are observed. Time dependence of the electric charge in the superconducting layers and charge-charge correlation functions for TW and outermost branches show different behavior with bias current. We propose an experimental testing of the TW by microwave irradiation.Comment: Supplement : http://theor.jinr.ru/~hamdipur/lambda0.av

A past capture event at Sagittarius A* inferred from the fluorescent X-ray emission of Sagittarius B clouds

The fluorescent X-ray emission from neutral iron in the molecular clouds (Sgr B) indicates that the clouds are being irradiated by an external X-ray source. The source is probably associated with the Galactic central black hole (Sgr A*), which triggered a bright outburst one hundred years ago. We suggest that such an outburst could be due to a partial capture of a star by Sgr A*, during which a jet was generated. By constraining the observed flux and the time variability ($\sim$ 10 years) of the Sgr B's fluorescent emission, we find that the shock produced by the interaction of the jet with the dense interstellar medium represents a plausible candidate for the X-ray source emission.Comment: 7 pages, 1 figure, accepted for publication in MNRA

The twisted quantum affine algebra U_q(A^{(2)_2) and correlation functions of the Izergin-Korepin model

We derive the exchange relations of the vertex operators of $U_q(A_2^{(2)})$ and show that these vertex operators give the bosonization of the Izergin-Korepin model. We give an integral expression of the correlation functions of the Izergin-Korepin model and derive the difference equations which they satisfy.Comment: RevTex 15 page

STUDY OF THE MECHANISM OF EXPLOSIVE FORCE PRODUCTION ON QUICK LIFT MOTION BY ANALYSIS OF EMG AND MOTION

The aim of this study is to investigate how explosive force exerts during power clean (PC) motion. The subjects are ten skilleds and ten unskilleds. The joint trajectory and EMG during PC are recorded. The joint torque and its rate of torque development (RTD) are calculated from the obtained data. The joint stiffness is estimated from joint stiffness index (JSI) calculated from EMG of agonist and antagonist muscle pair. Experimental results indicated that the skilleds showed the double knee bent that is typically seen in a stretch-shortening cycle (SSC). Skilleds exerted large values of RTD and JSI just after a period of exerting their small values during SSC. It indicates that a much amount of elastic energy stored in a low stiffness state is instantly transferred to the upper segments in the successive high stiffness state by “tenodesis action” of muscles. This is why large RTD generates in the skilled

New formulation of Horava-Lifshitz quantum gravity as a master constraint theory

Both projectable and non-projectable versions of Horava-Lifshitz gravity face serious challenges. In the non-projectable version, the constraint algebra is seemingly inconsistent. The projectable version lacks a local Hamiltonian constraint, thus allowing for an extra scalar mode which can be problematic. A new formulation of non-projectable Horava-Lifshitz gravity, naturally realized as a representation of the master constraint algebra studied by loop quantum gravity researchers, is presented. This yields a consistent canonical theory with first class constraints. It captures the essence of Horava-Lifshitz gravity in retaining only spatial diffeomorphisms (instead of full space-time covariance) as the physically relevant non-trivial gauge symmetry; at the same time the local Hamiltonian constraint needed to eliminate the extra mode is equivalently enforced by the master constraint.Comment: 4 page