We consider nonstationary spherically symmetric $n$-dimensional charged black holes with varying mass $m(v)$ and/or electric charge $q(v)$, described by generic charged Vaidya metrics with cosmological constant $\Lambda$ in double-null coordinates and perform a comprehensive numerical analysis of the fundamental quasinormal modes (QNM) for minimally coupled scalar fields. We show that the instantaneous quasinormal frequencies exhibit the same sort of nonstationary behavior reported previously for the four-dimensional uncharged case with $\Lambda =0$. Such property seems to be very robust, independent of the spacetime dimension and of the metric parameters, provided they be consistent with the existence of an event horizon. The study of time-dependent Reissner-Nordström black holes allows us to go a step further and quantify the deviation of the stationary regime for QNM with respect to charge variations as well. We also look for signatures in the quasinormal frequencies from the creation of a Reissner-Nordström naked spacetime singularity. Even though one should expect the breakdown of our approach in the presence of naked singularities, we show that it is possible, in principle, to obtain some information about the naked singularity from the QNM frequencies, in agreement with the previous results of Ishibashi and Hosoya showing that it would be indeed possible to have regular scattering from naked singularities.

Stationary axisymmetric systems of two extreme Kerr sources separated by a massless strut, which arise as subfamilies of the well-known Kinnersley-Chitre solution, are studied. We present explicit analytical formulas for the individual masses and angular momenta of the constituents and establish the range of the parameters for which such systems can be regarded as describing black holes. The mass-angular momentum relations and the interaction force in the black-hole configurations are also analyzed. Furthermore, we construct a charging generalization of the Kinnersley-Chitre metric and, as applications of the general formulas obtained, discuss two special cases describing a pair of identical co- and counter-rotating extreme Kerr-Newman black holes kept apart by a conical singularity. From our analysis it follows, in particular, that the equality $m^2-a^2-e^2=0$ relating the mass, angular momentum per unit mass and electric charge of a single Kerr-Newman extreme black hole is no longer verified by the analogous extreme black-hole constituents in binary configurations.

We develop a concept of parallel existence of the ordinary (O) and hidden (H) worlds. We compare two cases: (1) when the hidden sector of the Universe is a mirror counterpart of the ordinary world, and (2) when it is a superstring-inspired shadow world described, in contrast to the mirror world, by a symmetry group (or by a chain of groups), which does not coincide with the ordinary world symmetry group. We construct a cosmological model assuming the existence of the superstring-inspired $E_6$ unification, broken at the early stage of the Universe to $SO(10)\times U(1{)}_Z$—in the O-world, and to $SU(6{)}^{\prime }\times SU(2{)}_{\theta }^{\prime }$—in the H-world. As a result, we obtain the low-energy symmetry group $G_{\mathrm{SM}}^{\prime }\times SU(2{)}_{\theta }^{\prime }$ in the shadow world, instead of the standard model group $G_{\mathrm{SM}}$ existing in the O-world. The additional non-Abelian $SU(2{)}_{\theta }^{\prime }$ group with massless gauge fields, ”thetons,” is responsible for dark energy. Considering a quintessence model of cosmology with an inflaton $\sigma$ and an axion $a_{\theta }$, which is a pseudo Nambu-Goldstone boson induced by the $SU(2{)}_{\theta }^{\prime }$-group anomaly, we explain the origin of dark energy, dark matter and ordinary matter. In the present model we review all cosmological epochs (inflation, reheating, recombination and nucleosynthesis), and give our version of the baryogenesis. The cosmological constant problem is also briefly discussed.

We update the constraints on possible features in the primordial inflationary density perturbation spectrum by using the latest data from the WMAP7 and ACT (Atacama Cosmology Telescope) cosmic microwave background experiments. The inclusion of new data significantly improves the constraints with respect to older work, especially to smaller angular scales. While we found no clear statistical evidence in the data for extensions to the simplest, featureless, inflationary model, models with a step provide a significantly better fit than standard featureless power-law spectra. We show that the possibility of a step in the inflationary potential like the one preferred by current data will soon be tested by the forthcoming temperature and polarization data from the Planck satellite mission.

We show a model of the slow expansion, in which the scale invariant spectrum of curvature perturbation is adiabatically induced by its increasing mode, by applying a generalized Galileon field. In this model, initially $ϵ\ll -1$, which then rapidly increases, and during this period the Universe is slowly expanding. There is no ghost instability, and the perturbation theory is healthy. When $ϵ\sim -1$, the slow expansion phase ends, the available energy of field can be released and the Universe reheats. This scenario might be a viable design of the early Universe.

We explore the impact of a $\Lambda \mathrm{WDM}$ cosmological scenario on the clustering properties large-scale structure in the Universe. We do this by extending the halo model. The new development is that we consider two components to the mass density: one arising from mass in collapsed haloes, and the second from a smooth component of uncollapsed mass. Assuming that the nonlinear clustering of dark matter haloes can be understood, then from conservation arguments one can precisely calculate the clustering properties of the smooth component and its cross correlation with haloes. We then explore how the three main ingredients of the halo calculations, the halo mass function, bias and density profiles are affected by warm dark matter (WDM). We show that, relative to cold dark matter (CDM), the halo mass function is suppressed by 50%, for masses $\sim 100$ times the free-streaming mass scale $M_{\mathrm{fs}}$. Consequently, the bias of low mass haloes can be boosted by as much as $\sim 20\%$ for 0.25 keV WDM particles. Core densities of haloes will also be suppressed relative to the CDM case. We also examine the impact of relic thermal velocities on the density profiles, and find that these effects are constrained to scales $r<1h^{-1}\mathrm{kpc}$, and hence of little importance for dark matter tests, owing to uncertainties in the baryonic physics. We use our modified halo model to calculate the nonlinear matter power spectrum, and find that there is significant small-scale power in the model. However, relative to the CDM case the power is suppressed. The amount of suppression depends on the mass of the WDM particle, but can be of order 10% at $k\sim 1h{\mathrm{Mpc}}^{-1}$ for particles of mass 0.25 keV. We then calculate the expected signal and noise that our set of $\Lambda \mathrm{WDM}$ models would give for a future weak lensing mission. We show that the models should in principle be separable at high significance. Finally, using the Fisher matrix formalism we forecast the limit on the WDM particle mass for a future full-sky weak lensing mission like Euclid or the Large Synoptic Survey Telescope. With Planck priors and using only multipoles $l<5000$, we find that a lower limit of 2.6 keV should be easily achievable.

We consider a five-dimensional action which is composed of a gravitational sector and a sector of matter, where the gravitational sector is given by a Chern-Simons gravity action instead of the Einstein-Hilbert action. In the event that the matter action is the action for a perfect fluid, it is shown that the standard five-dimensional Friedmann-Robertson-Walker (FRW) equations and some of their solutions can be obtained, in a certain limit, from the so-called Chern-Simons-FRW field equations, which are the cosmological field equations corresponding to a Chern-Simons gravity theory. It is also shown, using a compactification procedure known as dynamic compactification, that the cosmological field equations obtained from the Chern-Simons gravity theory lead, in a certain limit, to the usual four-dimensional FRW equations.

The halo model (HM) describes the inhomogeneous universe as a collection of halos. The full nonlinear power spectrum of the universe is well approximated by the HM, whose prediction can be easily computed without lengthy numerical simulations. This makes the HM a useful tool in cosmology. Here we explore the lensing properties of the HM by use of the stochastic gravitational lensing method. We obtain for the case of point sources exact and simple integral expressions for the expected value and variance of the lensing convergence, which encode detailed information about the internal halo properties. In particular a wide array of observational biases can be easily incorporated and the dependence of lensing on cosmology is properly taken into account. This simple setup should be useful for a quick calculation of the power spectrum and the related lensing observables, which can play an important role in the extraction of cosmological parameters from, e.g., supernovae observations. Finally, we discuss the probability distribution function of the HM which encodes more information than the first two moments and can more strongly constrain the large-scale structures of the universe. To check the accuracy of our modeling we compare our predictions to the results from the Millennium Simulation.

We examine models in which the dark energy density increases with time (so that the equation-of-state parameter $w$ satisfies $w<-1$), but $w\to -1$ asymptotically, such that there is no future singularity. We refine previous calculations to determine the conditions necessary to produce this evolution. Such models can display arbitrarily rapid expansion in the near future, leading to the destruction of all bound structures (a “little rip”). We determine observational constraints on these models and calculate the point at which the disintegration of bound structures occurs. For the same present-day value of $w$, a big rip with constant $w$ disintegrates bound structures earlier than a little rip.

We analyze the optical spring characteristics of a double pumped Fabry-Perot cavity. A double-resonance optical spring occurs when the optical spring frequency and the detuning frequency of the cavity coincide. We formulate a simple criterion for the stability of an optical spring and apply it to the double-resonance regime. Double-resonance configurations are very promising for future gravitational-wave detectors as they allow us to surpass the Standard Quantum Limit. We show that stable double resonance can be demonstrated in middle scale prototype interferometers such as the Glasgow 10 m-Prototype, Gingin High Optical Power Test Facility or the AEI 10 m Prototype Interferometer before being implemented in future gravitational-wave detectors.

The large-scale clustering of galaxies can serve as a probe of primordial non-Gaussianity in the Universe competitive with the anisotropies of the cosmic microwave background. Here, we present improved theoretical predictions which include an important, previously overlooked correction to the bias. We demonstrate that the new predictions are able to reproduce the results of N-body simulations, explaining the significant departures seen from previous theoretical results. These refined predictions open the way to accurate constraints on primordial physics with large-scale structure surveys.

The XENON100 experiment has completed a dark matter search with 100.9 live days of data, taken from January to June 2010. Events with energies between 8.4 and $44.6{\mathrm{keV}}_{\mathrm{nr}}$ in a fiducial volume containing 48 kg of liquid xenon have been analyzed. A total of three events have been found in the predefined signal region, compatible with the background prediction of ($1.8\pm 0.6$) events. Based on this analysis we present limits on the WIMP-nucleon cross section for inelastic dark matter. With the present data we are able to rule out the explanation for the observed DAMA/LIBRA modulation as being due to inelastic dark matter scattering off iodine, at a 90% confidence level.

We study the QCD phase diagram at finite temperature and baryon chemical potential by relating the behavior of the light-quark condensate to the threshold energy for the onset of perturbative QCD. These parameters are connected to the chiral symmetry restoration and the deconfinement phase transition, respectively. This relation is obtained in the framework of finite energy QCD sum rules at finite temperature and density, with input from Schwinger-Dyson methods to determine the light-quark condensate. Results indicate that both critical temperatures are basically the same within some 3% accuracy. We also obtain bounds for the position of the critical end point, ${\mu }_{Bc}\gtrsim 300\mathrm{MeV}$ and $T_c\lesssim 185\mathrm{MeV}$.

This paper considers unitarity and $CPT$ constraints on asymmetric freeze-in, the use of freeze-in to store baryon number in a dark sector. In this scenario, Sakharov’s out-of-equilibrium condition is satisfied by placing the visible and hidden sectors at different temperatures while a net visible baryon number is produced by storing negative baryon number in a dark sector. It is shown that unitarity and $CPT$ lead to unexpected cancellations. In particular, the transfer of baryon number cancels completely at leading order.

We apply a previously developed scheme to consistently include the twist-3 distribution amplitudes for transversely polarized $\rho$ mesons in order to evaluate, in the framework of $k_T$ factorization, the helicity amplitudes for exclusive leptoproduction of a light vector meson, at leading order in ${\alpha }_s$. We compare our results with high energy experimental data for the ratios of helicity amplitudes $T_{11}/T_{00}$ and $T_{01}/T_{00}$ and get a good description of the data.

We present a simple formalism for the evolution of timelike jets in which tree-level matrix-element corrections can be systematically incorporated, up to arbitrary parton multiplicities and over all of phase space, in a way that exponentiates the matching corrections. The scheme is cast as a shower Markov chain which generates one single unweighted event sample, that can be passed to standard hadronization models. Remaining perturbative uncertainties are estimated by providing several alternative weight sets for the same events, at a relatively modest additional overhead. As an explicit example, we consider $Z\to q\overline{q}$ evolution with unpolarized, massless quarks and include several formally subleading improvements as well as matching to tree-level matrix elements through ${\alpha }_s^4$. The resulting algorithm is implemented in the publicly available Vincia plugin to the Pythia 8 event generator. The plug-in is available from the web site: http://projects.hepforge.org/vincia/.

This paper reports the values of contributions to the electron $g-2$ from 300 Feynman diagrams of the gauge-invariant Set III(a) and 450 Feynman diagrams of the gauge-invariant Set III(b). The evaluation is carried out in two versions. Version A is to start from the sixth-order magnetic anomaly $M_6$ obtained in the previous work. The mass-independent contributions of Set III(a) and Set III(b) are 2.1275(2) and 3.3271(6) in units of $(\alpha /\pi {)}^5$, respectively. Version B is based on the recently developed automatic code generation scheme. This method yields 2.1271(3) and 3.3271(8) in units of $(\alpha /\pi {)}^5$, respectively. They are in excellent agreement with the results of the first method within the uncertainties of numerical integration. Combining these results as statistically independent we obtain the best values, 2.1273(2), and 3.3271(5) times $(\alpha /\pi {)}^5$, for the mass-independent contributions of the Set III(a) and Set III(b), respectively. We have also evaluated mass-dependent contributions of diagrams containing muon and/or tau-particle loop. Including them the total contribution of Set III(a) is 2.1349(2) and that of Set III(b) is 3.3299(5) in units of $(\alpha /\pi {)}^5$. The total contributions to the muon $g-2$ of various leptonic vacuum-polarization loops of Set III(a) and Set III(b) are 112.418(32) and 15.407(5) in units of $(\alpha /\pi {)}^5$, respectively.

Recently T2K experiment gives hint in favor of large reactor angle ${\theta }_{13}$. Most of the models, with tribimaximal mixing at the leading order, can not reproduce such a large mixing angle since they predict typically corrections for the reactor angle of the order ${\theta }_{13}\sim {\lambda }_C^2$, where ${\lambda }_C\sim 0.2$. In this paper, we discuss the possibility to achieve large ${\theta }_{13}$ within the T2K region with maximal atmospheric mixing angle, ${sin}^2{\theta }_{23}=1/2$, and trimaximal solar mixing angle, ${sin}^2{\theta }_{12}=1/3$, through the deviation from the exact tribimaximal mixing. We derive the structure of neutrino mass matrix that leads to the large ${\theta }_{13}$ leaving maximal ${\theta }_{23}$ and trimaximal ${\theta }_{12}$. It is shown that such a structure of neutrino mass matrix can arise in a model with $S_4$ flavor symmetry.

Neutrinos may mix with ultralight fermions, which gives flavor oscillations, and with heavier fermions, which yields short distance flavor change. I consider the case where both effects are present. I show that in the limit where a single oscillation length is experimentally accessible, the effects of heavier fermions on short baseline neutrino oscillations can generically be accounted for by a simple formula containing only four parameters, including observable $CP$ violation. I consider the anomalous LSND and MiniBooNE results, and show that these can be fit in a model with $CP$ violation and two additional sterile neutrinos, one in the mass range between 0.1 and 20 eV, and the other with mass between 32 eV and 40 GeV. I also show that this model can avoid conflict with constraints from existing null short baseline experimental results.

Evidence of massive neutrinos in the ${\pi }^{+}\to e^{+}\nu$ decay spectrum was sought with the background ${\pi }^{+}\to {\mu }^{+}\to e^{+}$ decay chain highly suppressed. Upper limits (90% C.L.) on the neutrino mixing matrix element $|U_{ei}{|}^2$ in the neutrino mass region $60–129\mathrm{MeV}/c^2$ were set at the level of ${10}^{-8}$.