14066348
Spherical collapse model with non-clustering dark energy
We investigate a spherical overdensity model for the non-clustering dark energy (DE) with the constant equation of state, ωde in a flat universe. In this case, the exact solution for the evolution of the scale factor is obtained for general ωde. We also obtain the exact (when ωde = −1/3) and the approximate (when ωde≠−1/3) solutions for the ratio of the overdensity radius to its value at the turnaround epoch (y≡R/Rta) for general cosmological parameters. Also the exact and approximate solutions of the overdensity at the turnaround epoch ζ = (ρcluster/ρm)|z = zta are obtained for general ωde. Thus, we are able to obtain the non-linear overdensity Δ≡1+δNL = ζ(x/y)3 at any epoch for the given DE model. The non-linear overdensity at the virial epoch Δvir = ζ(xvir/yvir)3 is obtained by using the virial theorem and the energy conservation. The non-linear overdensity of every DE model converges to that of the Einstein de Sitter universe ΔvirEdS = 18π2((1/2π)+(3/4))2 147 when zvir increases. We find that the observed quantities at high redshifts are insensitive to the different ωde models. The low-redshift cluster (zvir ~ 0.04, i.e., zta ~ 0.7) shows the most model dependent feature and it should be a suitable object for testing DE models. Also as ΩM0 increases, the model dependence of the observed quantities decreases. The error in the approximate solutions is at most 2% for a wide range of the parameter space. Even though the analytic forms of y and ζ are obtained for the constant ωde, they can be generalized to the slowly varying ωde. Thus, these analytic forms of the scale factor, y, and ζ provide a very accurate and useful tool for measuring the properties of DE.
117762235
Correct sub-horizon scales linear perturbation equation for general dark energy models
3165699
Growth index in an accelerating universe
We obtain the exact analytic form of growth index ($f = \Omega_{m}(a)^{\gamma}$) at present epoch in a flat universe for the general value of constant equation of state of dark energy $\omega_{de}$. For the cosmological constant ($\omega_{de} = -1$) we obtain $\gamma = 0.5547$ which is very close to the well known value 6/11. However, if $\omega_{de} = -0.9$, then $\gamma$ gives rise to 0.6405. This result is quite different from that of some other literatures. This discrepancy happens because the numerical solution includes not only the growing mode solution but also the decaying one in some literatures. Thus, the numerical estimation of $\delta$ is over estimated in some references. $\Omega_{m}^{0}$ dependence of $\gamma$ is fairly small for the viable range of the current matter energy density $0.2 \leq \Omega_{m}^{0} \leq 0.3$. (0.6% and 3% changes in $\gamma$ for $\omega_{de}$ equal to -1 and -0.9, respectively.) The difference of peculiar velocity values from the different choices of $\gamma$ is about 11% for $\Omega_{m}^{0} = 0.3$. This simple but accurate formula which covers a large class of dark energy models will provide a practical tool for galaxy redshift survey to measure the matter density and the peculiar velocity.
1970563
Can strong gravitational lensing constrain dark energy
We discuss the ratio of the angular diameter distances from the source to the lens, D{sub ds}, and to the observer at present, D{sub s}, for various dark energy models. It is well known that the difference of D{sub s}s between the models is apparent and this quantity is used for the analysis of Type Ia supernovae. However we investigate the difference between the ratio of the angular diameter distances for a cosmological constant, (D{sub ds}/D{sub s}){sup {lambda}}, and that for other dark energy models, (D{sub ds}/D{sub s}){sup other}, in this paper. It has been known that there is lens model degeneracy in using strong gravitational lensing. Thus, we investigate the model independent observable quantity, Einstein radius ({theta}{sub E}), which is proportional to both D{sub ds}/D{sub s} and velocity dispersion squared, {sigma}{sub v}{sup 2}. D{sub ds}/D{sub s} values depend on the parameters of each dark energy model individually. However, (D{sub ds}/D{sub s}){sup {lambda}}-(D{sub ds}/D{sub s}){sup other} for the various dark energy models, is well within the error of {sigma}{sub v} for most of the parameter spaces of the dark energy models. Thus, a single strong gravitational lensing by use of the Einstein radius may not be a proper method tomore » investigate the property of dark energy. However, better understanding to the mass profile of clusters in the future or other methods related to arc statistics rather than the distances may be used for constraints on dark energy.« less
118495217
Evidence for departure from \Lambda CDM with LSS
We investigate the growth index parameter \gamma and the time variation of the gravitational constant G_{eff} by using the currently available growth function f(z) data at different redshifts, with and without scaling to the fiducial \Lambda CDM model. We inquire the four different models of \gamma including a constant \gamma. From a \chi^2 minimization, we constrain the parameter spaces of models and show that \Lambda CDM model is excluded by 1-\sigma level from current f(z) data. G_{eff} is different from the Newton's gravitational constant G_{N} in modified gravity theories and interestingly, the current data shows that G_{eff} \neq G_{N} at z \gtrsim 0.2 \sim 0.3 at 3-\sigma level. From these, we conclude that Einstein's General Relativity with \Lambda CDM is ruled out by 99% confidence level from large scale structure observations.
15011888
Effect on cosmic microwave background polarization of coupling of quintessence to pseudoscalar formed from the electromagnetic field and its dual.
We present the full set of power spectra of cosmic microwave background (CMB) temperature and polarization anisotropies due to the coupling between quintessence and pseudoscalar of electromagnetism. This coupling induces a rotation of the polarization plane of the CMB, thus resulting in a nonvanishing B mode and parity-violating TB and EB modes. Using the BOOMERANG data from the flight of 2003, we derive the most stringent constraint on the coupling strength. We find that in some cases the rotation-induced B mode can confuse the hunting for the gravitational lensing-induced B mode.
119474240
Model-independent properties of the B-meson distribution amplitude
The operator product expansion is used to obtain model-independent predictions for the first two moments of the renormalized $B$-meson light-cone distribution amplitude ${\ensuremath{\phi}}_{+}^{B}(\ensuremath{\omega},\ensuremath{\mu})$, defined with a cutoff $\ensuremath{\omega}\ensuremath{\le}{\ensuremath{\Lambda}}_{\mathrm{UV}}$. The leading hadronic power corrections are given in terms of the parameter $\overline{\ensuremath{\Lambda}}={m}_{B}\ensuremath{-}{m}_{b}$. From the cutoff dependence of the zeroth moment an analytical expression for the asymptotic behavior of the distribution amplitude is derived, which exhibits a negative radiation tail for $\ensuremath{\omega}\ensuremath{\gg}\ensuremath{\mu}$. By solving the evolution equation for the distribution amplitude, an integral representation for ${\ensuremath{\phi}}_{+}^{B}(\ensuremath{\omega},\ensuremath{\mu})$ is obtained in terms an initial function ${\ensuremath{\phi}}_{+}^{B}(\ensuremath{\omega},{\ensuremath{\mu}}_{0})$ defined at a lower renormalization scale. A realistic model of the $B$-meson light-cone distribution amplitude is proposed, which satisfies the moment relations and has the correct asymptotic behavior. This model provides an estimate for the first inverse moment and the associated parameter ${\ensuremath{\lambda}}_{B}$.
118377735
Free energy versus internal energy potential for heavy quark systems at finite temperature
Using the QCD sum rule with its operator product expansion reliably determined from lattice calculations for the pressure and energy density of hot QCD matter, we calculate the strength of the $J/\ensuremath{\psi}$ wave function at the origin and find that it decreases with temperature when the temperature is in the vicinity of the transition temperature. This result is shown to follow exactly that obtained from the solution of the Schr\"odinger equation for a charm and anticharm quark pair with a temperature independent quark mass using the free energy from lattice calculations as the potential and is in sharp contrast to that using the deeper potential associated with the internal energy, which shows an enhanced strength of the $J/\ensuremath{\psi}$ wave function at the origin. Our result thus suggests that the free energy potential from lattice calculations is the appropriate heavy-quark potential for analyzing the charmonium spectrum at a finite temperature.
91854570
Effects of chiral symmetry restoration in nuclear medium
119851008
COMPOSITENESS OF EXTERNAL PARTICLE AND ABSENCE OF FIXED POLES IN PHOTOPRODUCTION PROCESSES.
118483089
Holographic description of large N gauge theory
Abstract Based on the earlier work [S.-S. Lee, Nucl. Rev. B 832 (2010) 567], we derive a holographic dual for the D -dimensional U ( N ) lattice gauge theory from a first principle construction. The resulting theory is a lattice field theory of closed loops, dubbed as lattice loop field theory which is defined on a ( D + 1 ) -dimensional space. The lattice loop field theory is well defined non-perturbatively, and it becomes weakly coupled and local in the large N limit with a large ʼt Hooft coupling.