We propose a regular black hole whose inside generates a de Sitter space and then is finally frustrated into a singularity. It is a modified model which was suggested originally by Frolov, Markov, and Mukhanov. In our model, we could adjust a regular black hole so that its period before going into the extreme state is much longer than the information retention time. During this period an observer could exist who observes the information of the Hawking radiation, falls freely into the regular center of the black hole, and finally meets the free-falling information again. The existence of such an observer implies that the complementary view may not be consistent with a regular black hole, and therefore, is not appropriate as a generic principle of black hole physics.

We compare results from numerical simulations of spinning binaries in the “orbital hang-up” case, where the binary completes at least nine orbits before merger, with post-Newtonian results using the approximants Taylor T1, T4, and Et. We find that, over the ten cycles before the gravitational-wave frequency reaches $M\omega =0.1$, the accumulated phase disagreement between numerical relativity (NR) and 2.5 post-Newtonian (PN) results is less than three radians, and is less than 2.5 radians when using 3.5PN results. The amplitude disagreement between NR and restricted PN results increases with the black holes’ spin, from about 6% in the equal-mass case to 12% when the black holes’ spins are $S_i/M_i^2=0.85$. Finally, our results suggest that the merger waveform will play an important role in estimating the spin from such inspiral waveforms.

We use a combination of analytic tools and an extensive set of the largest and most accurate three-dimensional field theory numerical simulations to study the dynamics of domain wall networks with junctions. We build upon our previous work and consider a class of models which, in the limit of large number $N$ of coupled scalar fields, approaches the so-called “ideal” model (in terms of its potential to lead to network frustration). We consider values of $N$ between $N=2$ and $N=20$, and a range of cosmological epochs, and we also compare this class of models with other toy models used in the past. In all cases we find compelling evidence for a gradual approach to scaling, strongly supporting our no-frustration conjecture. We also discuss the various possible types of junctions (including cases where there is a hierarchy of them) and their roles in the dynamics of the network. Finally, we provide a cosmological Zel’dovich-type bound on the energy scale of this kind of defect network: it must be lower than 10 keV.

The sensitivity of inflationary spectra to initial conditions is addressed in the context of a phenomenological model that breaks Lorentz invariance by dissipative effects above some threshold energy $\Lambda$. These effects are obtained dynamically by coupling the fluctuation modes to extra degrees of freedom which are unobservable below $\Lambda$. Because of the strong dissipative effects in the early propagation, only the state of the extra degrees of freedom is relevant for the power spectrum. If this state is the ground state, and if $\Lambda$ is much larger than the Hubble scale $H$, the standard spectrum is recovered. Using analytical and numerical methods, we calculate the modifications for a large class of dissipative models. For all of these, we show that the leading modification (in an expansion in $H/\Lambda$) is linear in the decay rate evaluated at horizon exit, and that high frequency superimposed oscillations are not generated. The modification is negative when the decay rate decreases slower than the cube of $H$, which means that there is a loss of power on the largest scales.

We study Dvali-Gabadadze-Porrati (DGP) braneworlds with finite thickness. In respect to the standard (thin) DGP Friedmann equation, finite thickness of the brane causes a subtle modification of the cosmological equations that can lead to significant physical consequences. The resulting cosmology is governed by two length scales which are associated with the brane thickness and with the crossover length, respectively. In this setup both early inflation and late-time acceleration of the expansion are a consequence of the 5D geometry. At early times, as well as at late times, 5D effects become dominant (gravity leaks into the extra dimension), while, at intermediate times, gravity is effectively 4D due to nontrivial physics occurring in standard (thin) DGP scenarios.

Greybody factors in black-hole physics modify the naive Planckian spectrum that is predicted for Hawking radiation when working in the limit of geometrical optics. We consider the Schwarzschild geometry in $(3+1)$ dimensions, and analyze the Regge-Wheeler equation for arbitrary particle spin $s$ and wave-mode angular momentum $\ell$, deriving rigorous bounds on the greybody factors as a function of $s$, $\ell$, wave frequency $\omega$, and the black-hole mass $m$.

The neutrinoless and neutrinos double beta decays are investigated in an effective theory where a scalar unparticle is introduced. We calculate the contributions of a virtual unparticle to the rates of $0\nu 2\beta$ and $2\nu 2\beta$ decays. The unparticle effect is negligibly small when the scaling dimension $d$ of unparticle lies in the region $1.1–1.9$. But it can be relatively large when $d$ approaches to 1 or 2. We also study the neutrinoless double beta decay with a real unparticle in the final state which cannot be distinguished from $2\nu 2\beta$ decay in experiment. We consider the unparticle effect on extracting the neutrino mass parameter $m_{\beta \beta }$ from experimental data and find that it can be relatively large when $d$ takes certain values.

We present rigorous upper and lower bounds for the momentum-space ghost propagator $G(p)$ of Yang-Mills theories in terms of the smallest nonzero eigenvalue (and of the corresponding eigenvector) of the Faddeev-Popov matrix. We apply our analysis to data from simulations of SU(2) lattice gauge theory in Landau gauge, using the largest lattice sizes to date. Our results suggest that, in three and in four space-time dimensions, the Landau gauge ghost propagator is not enhanced as compared to its tree-level behavior. This is also seen in plots and fits of the ghost dressing function. In the two-dimensional case, on the other hand, we find that $G(p)$ diverges as $p^{-2-2\kappa }$ with $\kappa \approx 0.15$, in agreement with A. Maas, Phys. Rev. D 75, 116004 (2007). We note that our discussion is general, although we make an application only to pure gauge theory in Landau gauge. Our simulations have been performed on the IBM supercomputer at the University of São Paulo.

We investigate the behavior of the critical charge for spontaneous pair production, $Z_C$, defined as the charge at which the total energy of a $K$-shell electron is $E=-m_e$, as a function of the radius $R$ of the charge distribution. Our approach is to solve the Dirac equation for a potential $V(r)$ consisting of a spherically symmetrical charge distribution of radius $R$ and a Coulomb tail. For a spherical shell distribution of the type usually associated with color-flavor locked strange quark nuggets, we confirm the relation $Z_C=0.71R(\mathrm{fm})$ for sufficiently large $R$ obtained by Madsen, who used an approach based on the Thomas-Fermi model. We also present results for a uniformly charged sphere and again find that $Z_C\sim R$ for large enough $R$. Also discussed is the behavior of $Z_C$ when simple ad hoc modifications are made to the potential for $0\le r<R$.

Recently, a curious neutrino mass matrix has been proposed: it is related to up-quark masses, and it can excellently give a nearly tribimaximal mixing. It is pointed out that, in order to obtain such successful results, three phenomenological relations among masses and Cabibbo-Kobayashi-Maskawa parameters must be simultaneously satisfied. This suggests that there must be a specific flavor basis in which down-quark and charged lepton mass matrices are simultaneously diagonalized.

At tree-level Higgs production in association with a $b$-quark pair proceeds through the small Yukawa bottom coupling in the standard model. Even in the limit where this coupling vanishes, electroweak one-loop effects, through the top-Higgs Yukawa coupling, in particular, can still trigger this reaction. This contribution is small for Higgs masses around 120 GeV but it quickly picks up for higher Higgs masses especially because the one-loop amplitude develops a leading Landau singularity and new thresholds open up. These effects can be viewed as the production of a pair of top quarks which rescatter to give rise to Higgs production through $WW$ fusion. We study the leading Landau singularity in detail. Since this singularity is not integrable when the one-loop amplitude is squared, we regulate the cross section by taking into account the width of the internal top and $W$ particles. This requires that we extend the usual box one-loop function to the case of complex masses. We show how this can be implemented analytically in our case. We study in some detail the cross section at the CERN LHC as a function of the Higgs mass and show how some distributions can be drastically affected compared to the tree-level result.

Ambient noise measured in the deep ocean is studied in the context of a search for signals from ultrahigh-energy cosmic ray neutrinos. The spectral shape of the noise at the relevant high frequencies is found to be very stable for an extensive data set collected over several months from 49 hydrophones mounted near the bottom of the ocean at $\sim 1600\mathrm{m}$ depth. The slopes of the ambient noise spectra above 15 kHz are found to roll off faster than the $-6\mathrm{dB}/\mathrm{\text{octave}}$ seen in Knudsen spectra. A model attributing the source to a uniform distribution of surface noise that includes frequency-dependent absorption at large depth is found to fit the data well up to 25 kHz. This depth-dependent model should therefore be used in analysis methods of acoustic neutrino pulse detection that require the expected noise spectra.

We consider a Casimir apparatus consisting of two perfectly conducting parallel plates, subject to the weak gravitational field of the Earth. The aim of this paper is the calculation of the energy-momentum tensor of this system for a free, real massless scalar field satisfying Neumann boundary conditions on the plates. The small gravity acceleration (considered here as not varying between the two plates) allows us to perform all calculations to first order in this parameter. Some interesting results are found: a correction, depending on the gravity acceleration, to the well-known Casimir energy and pressure on the plates. Moreover, this scheme predicts a tiny force in the upwards direction acting on the apparatus. These results are supported by two consistency checks: the covariant conservation of the energy-momentum tensor and the vanishing of its regularized trace, when the scalar field is conformally coupled to gravity.

We present a simple mechanism for obtaining large-field inflation, and hence a gravitational wave signature, from string theory compactified on twisted tori. For nil manifolds, we obtain a leading inflationary potential proportional to ${\varphi }^{2/3}$ in terms of the canonically normalized field $\varphi$, yielding predictions for the tilt of the power spectrum and the tensor-to-scalar ratio, $n_s\approx 0.98$ and $r\approx 0.04$ with 60 e-foldings of inflation; we note also the possibility of a variant with a candidate inflaton potential proportional to ${\varphi }^{2/5}$. The basic mechanism involved in extending the field range—monodromy in $D$-branes as they move in circles on the manifold—arises in a more general class of compactifications, though our methods for controlling the corrections to the slow-roll parameters require additional symmetries.

In this paper we shed new light on the AdS/CFT duality by interpreting the CFT as the Fourier transform in AdS space. We make use of well-known integral geometry techniques to derive the Fourier transformation of a function defined on the AdS hyperboloid. We show that the Fourier transformation of a function on the hyperboloid is a function defined on the boundary. We find that the Green’s functions from the literature are actually the Fourier weights (i.e. plane wave solutions) of the transformation and that the boundary values of fields appearing in the correspondence are the Fourier components of the transformation. One is thus left to interpret the CFT as the quantized version of a classical theory in AdS and the dual operator as the Fourier coefficients. Group theoretic considerations are discussed in relation to the transformation and its potential use in constructing QCD-like theories. In addition, we consider possible implications involving understanding the dual of AdS black holes.

The Dirac spectrum of QCD with dynamical fermions at nonzero chemical potential is characterized by three regions: a region with a constant eigenvalue density, a region where the eigenvalue density shows oscillations that grow exponentially with the volume and the remainder of the complex plane where the eigenvalue density is zero. In this paper we derive the phase diagram of the Dirac spectrum from a chiral Lagrangian. We show that the constant eigenvalue density corresponds to a pion condensed phase while the strongly oscillating region is given by a kaon condensed phase. The normal phase with nonzero chiral condensate but vanishing Bose condensates coincides with the region of the complex plane where there are no eigenvalues.

We examine the renormalization of Lee-Wick gauge theory to one-loop order. We show that only knowledge of the wave function renormalization is necessary to determine the running couplings, anomalous dimensions, and vector boson masses. In particular, the logarithmic running of the Lee-Wick vector boson mass is exactly related to the running of the coupling. In the case of an asymptotically free theory, the vector boson mass runs to infinity in the ultraviolet. Thus, the UV fixed point of the pure gauge theory is an ordinary quantum field theory. We find that the coupling runs more quickly in Lee-Wick gauge theory than in ordinary gauge theory, so the Lee-Wick standard model does not naturally unify at any scale. Finally, we present results on the beta function of more general theories containing dimension six operators which differ from previous results in the literature.

In this paper we study the possibility of sustaining an evolving wormhole via exotic matter made out of phantom energy. We show that this exotic source can support the existence of evolving wormhole spacetimes. Explicitly, a family of evolving Lorentzian wormholes conformally related to another family of zero-tidal force static wormhole geometries is found in Einstein gravity. Contrary to the standard wormhole approach, where first a convenient geometry is fixed and then the matter distribution is derived, we follow the conventional approach for finding solutions in theoretical cosmology. We derive an analytical evolving wormhole geometry by supposing that the radial tension (which is negative to the radial pressure) and the pressure measured in the tangential directions have barotropic equations of state with constant state parameters. At spatial infinity this evolving wormhole, supported by this anisotropic matter, is asymptotically flat, and its slices $t=\mathrm{\text{constant}}$ are spaces of constant curvature. During its evolution the shape of the wormhole expands with constant velocity, i.e without acceleration or deceleration, since the scale factor has strictly a linear evolution.

We apply spherical needlets to the Wilkinson Microwave Anisotropy Probe 5-year cosmic microwave background (CMB) data set, to search for imprints of nonisotropic features in the CMB sky. We use the needlets’ localization properties to resolve peculiar features in the CMB sky and to study how these features contribute to the anisotropy power spectrum of the CMB. In addition to the now well-known “cold spot” of the CMB map in the southern hemisphere, we also find two hot spots at greater than 99% confidence level, again in the southern hemisphere and closer to the Galactic plane. While the cold spot contributes to the anisotropy power spectrum in the multipoles between $\ell =6$ to $\ell =33$, the hot spots are found to be dominating the anisotropy power in the range between $\ell =6$ and $\ell =18$. Masking both the cold and the two hot spots results in a reduction by about 15% in the amplitude of the angular power spectrum of CMB around $\ell =10$. The resulting changes to the cosmological parameters when the power spectrum is estimated masking these features (in addition to the WMAP team’s KQ85 mask) are within the $1\sigma$ errors published with the WMAP mask only. We also study the asymmetry between the angular power spectra evaluated on the northern and southern hemispheres. When the features detected by needlets are masked, we find that the difference in the power, measured in terms of the anisotropy variance between $\ell =4$ and $\ell =18$, is reduced by a factor 2. We make available a mask related to needlet features for more detailed studies on asymmetries in the CMB anisotropy sky.

We consider energy deposition of high energy electrons and photons in the Universe. We carry out detailed calculations of fractions of the initial energy of the injected electron or photon which are used to heat, ionize, and excite background plasma in the early Universe for various ionization states (ionization $\mathrm{\text{fraction}}={10}^{-3}-1$) and redshifts ($z=100–1000$).