We study, by numerical methods, the time evolution of scalar perturbations in radiation era of Randall-Sundrum braneworld cosmology. Our results confirm an existence of the enhancement of perturbation amplitudes (near horizon crossing), discovered recently. We suggest the approximate solution of equations of the perturbation theory in the high-energy regime, which predicts that the enhancement factor is asymptotically constant, as a function of scale. We discuss the application of this result for the problem of primordial black hole production in braneworld cosmology.

The quantum theory of optical coherence is applied to the scrutiny of the statistical properties of the relic inflaton quanta. After adapting the description of the quantized scalar and tensor modes of the geometry to the analysis of intensity correlations, the normalized degrees of first-order and second-order coherence are computed in the concordance paradigm and are shown to encode faithfully the statistical properties of the initial quantum state. The strongly bunched curvature phonons are not only super-Poissonian but also superchaotic. Testable inequalities are derived in the limit of large-angular scales and can be physically interpreted in the light of the tenets of Hanbury Brown–Twiss interferometry. The quantum mechanical results are compared and contrasted with different situations including the one where intensity correlations are the result of a classical stochastic process. The survival of second-order correlations (not necessarily related to the purity of the initial quantum state) is addressed by defining a generalized ensemble where super-Poissonian statistics is an intrinsic property of the density matrix and turns out to be associated with finite volume effects which are expected to vanish in the thermodynamic limit.

In this work we consider an extended electromagnetic theory in which the scalar state which is usually eliminated by means of the Lorenz condition is allowed to propagate. This state has been shown to generate a small cosmological constant in the context of standard inflationary cosmology. Here we show that the usual Lorenz gauge-breaking term now plays the role of an effective electromagnetic current. Such a current is generated during inflation from quantum fluctuations and gives rise to a stochastic effective charge density distribution. Because of the high electric conductivity of the cosmic plasma after inflation, the electric charge density generates currents which give rise to both vorticity and magnetic fields on sub-Hubble scales. Present upper limits on vorticity coming from temperature anisotropies of the CMB are translated into lower limits on the present value of cosmic magnetic fields. We find that, for a nearly scale invariant vorticity spectrum, magnetic fields $B_{\lambda }>{10}^{-12}\mathrm{G}$ are typically generated with coherence lengths ranging from subgalactic scales up to the present Hubble radius. Those fields could act as seeds for a galactic dynamo or even account for observations just by collapse and differential rotation of the protogalactic cloud.

We have conducted a search for extended energy deposition trails left by ultrarelativistic magnetic monopoles interacting in Antarctic ice. The nonobservation of any satisfactory candidates in the 31 days of accumulated ANITA-II (Antarctic Impulsive Transient Antenna) flight data results in an upper limit on the diffuse flux of relativistic monopoles. We obtain a 90% C.L. limit of order ${10}^{-19}({\mathrm{cm}}^2\mathrm{s}\mathrm{sr}{)}^{-1}$ for values of Lorentz factor, $\gamma$, ${10}^{10}\le \gamma$ at the anticipated energy $E_{\mathrm{tot}}={10}^{16}\mathrm{GeV}$. This bound is stronger than all previously published experimental limits for this kinematic range.

Recent data from CREAM seem to confirm early suggestions that primary cosmic ray spectra at few $\mathrm{TeV}/\mathrm{nucleon}$ are harder than in the 10–100 GeV range. Also, helium and heavier nuclei spectra appear systematically harder than the proton fluxes at corresponding energies. We note here that if the measurements reflect intrinsic features in the interstellar fluxes (as opposed to local effects) appreciable modifications are expected in the sub-TeV range for the secondary yields, such as antiprotons and diffuse gamma rays. Presently, the ignorance on the origin of the features represents a systematic error in the extraction of astrophysical parameters as well as for background estimates for indirect dark matter searches. We find that the spectral modifications are appreciable above 100 GeV, and can be responsible for $\sim 30\%$ effects for antiprotons at energies close to 1 TeV or for gammas at energies close to 300 GeV, compared to currently considered predictions based on simple extrapolation of input fluxes from low-energy data. Alternatively, if the feature originates from local sources, uncorrelated spectral changes might show up in antiproton and high-energy gamma rays, with the latter ones likely dependent from the line of sight.

The classical modeling of radiation by accelerated charged particles in pulsars predicts a cutoff in photon energy at around 25 GeV. While this is broadly consistent with observations, the classical treatment is not self-consistent, and cannot be extended to explain the rare high-energy detections of photons in the 100s of GeV range. In this paper we revisit the theoretical modeling of high-energy radiation processes in very strong electromagnetic fields, in the context of both single particles and collective plasmas. There are no classical constraints on this description. We find that there is indeed a critical energy of around 50 GeV that arises naturally in this self-consistent treatment, but rather than being a cutoff, this critical energy signals a transition from radiation that is classical to a quasiquantum description, in which the particle is able to radiate almost its total energy in a single event. This new modeling therefore places pulsar radiation processes on a more secure physical basis, and admits the possibility of the production of TeV photons in a self-consistent way.

Future proposed satellite missions such as Euclid can offer the opportunity to test general relativity on cosmic scales through mapping of the galaxy weak-lensing signal. In this paper we forecast the ability of these experiments to constrain modified gravity scenarios such as those predicted by scalar-tensor and $f(R)$ theories. We find that Euclid will improve constraints expected from the Planck satellite on these modified theories of gravity by 2 orders of magnitude. We discuss parameter degeneracies and the possible biases introduced by modifications to gravity.

We investigate future constraints on early dark energy (EDE) achievable by the Planck and CMBPol experiments, including cosmic microwave background (CMB) lensing. For the dark energy, we include the possibility of clustering through a sound speed $c_s^2<1$ (cold dark energy) and anisotropic stresses parametrized with a viscosity parameter $c_{\mathrm{vis}}^2$. We discuss the degeneracies between cosmological parameters and EDE parameters. In particular we show that the presence of anisotropic stresses in EDE models can substantially undermine the determination of the EDE sound speed parameter $c_s^2$. The constraints on EDE primordial energy density are however unaffected. We also calculate the future CMB constraints on neutrino masses and find that they are weakened by a factor of 2 when allowing for the presence of EDE, and highly biased if it is incorrectly ignored.

We argue that experiments with ultracold neutrons in the gravitational field of Earth disprove recent speculations on the entropic origin of gravitation.

A new method for calculation of the mixing angle between the hadrons within QCD sum rules is proposed. In this method, the mixing is expressed in terms of quark and gluon degrees of freedom. As an application, the detailed calculation of the mixing angle between heavy cascade baryons ${\Xi }_Q$ and ${\Xi }_Q^{\prime }$, $Q=c$, $b$ is presented and it is found that the mixing angle between ${\Xi }_b$ (${\Xi }_c$) and ${\Xi }_b^{\prime }$ (${\Xi }_c^{\prime }$) is given by ${\theta }_b=6.4°\pm 1.8°$ (${\theta }_c=5.5°\pm 1.8°$).

In this paper we show that the skeleton diagrams in the $m$-Loop $n\mathrm{PI}$ effective action correspond to an infinite resummation of perturbative diagrams which is void of double counting at the $m$-Loop level. We also show that the variational equations of motion produced by the $n$-Loop $n\mathrm{PI}$ effective theory are equivalent to the Schwinger-Dyson equations, up to the order at which they are consistent with the underlying symmetries of the original theory. We use a diagrammatic technique to obtain the 5-Loop 5PI effective action for a scalar theory with cubic and quartic interactions, and verify that the result satisfies these two statements.

With the assumptions that dark matter consists of an electroweak triplet and that the gauge couplings unify at a high scale, we identify robust phenomenological trends of possible matter contents at the TeV scale. In particular, we expect new colored states within the LHC reach that can have Yukawa couplings $\lambda$ to quarks and the Higgs. We investigate the collider signatures that are characteristic of all such models by adopting the model with the simplest matter content as a benchmark. The $\lambda$ couplings are constrained by flavor/$CP$ physics. In the largest portion of the allowed parameter space the new colored particles are stable on collider time scales, hence appearing as $R$ hadrons, for which there is discovery potential at the early LHC ($\sqrt{s}=7\mathrm{TeV}$, $1{\mathrm{fb}}^{-1}$). Flavor/$CP$ constraints nevertheless do allow a sizable range of $\lambda$ where the new colored particles decay promptly, providing a new Higgs production channel with a cross section governed by the strong interaction. Studying the case of $h\to WW$, we show that it is possible for the Higgs production from this new channel to be discovered before that from the standard model at the LHC.

We give the first accurate results for $B$ and $B_s$ meson masses from lattice QCD including the effect of $u$, $d$, and $s$ sea quarks, and we improve an earlier value for the $B_c$ meson mass. By using the highly improved staggered quark (HISQ) action for $u/d$, $s$, and $c$ quarks and NRQCD for the $b$ quarks, we are able to achieve an accuracy in the masses of around 10 MeV. Our results are: $m_B=5.291(18)\mathrm{GeV}$, $m_{B_s}=5.363(11)\mathrm{GeV}$, and $m_{B_c}=6.280(10)\mathrm{GeV}$. Note that all QCD parameters here are tuned from other calculations, so these are parameter free-tests of QCD against experiment. We also give scalar, $B_{s0}^{*}$ and axial-vector, $B_{s1}$ meson masses. We find these to be slightly below threshold for decay to $BK$ and $B^{*}K$, respectively.

In this Comment we explain the discrepancies mentioned by the authors between their results and ours about the influence of the gravitational quadrupole moment in the perturbative calculation of corrections to the precession of the periastron of quasielliptical Keplerian equatorial orbits around a point mass. The discrepancy appears to be a consequence of two different calculations of the angular momentum of the orbits.

In the heavy quark limit of Coulomb gauge QCD and by truncating the Yang-Mills sector to include only dressed two-point functions, an analytic nonperturbative solution to the Faddeev equation for three-quark bound states in the case of equal quark separations is presented. A direct connection between the temporal gluon propagator and the three-quark confinement potential is provided and it is shown that only color-singlet $qqq$ (baryon) states are physically allowed.

In this paper, we examine the possibility to implement some form of emergent Newtonian gravity in a generic multicomponent Bose-Einstein condensate. Parallel to what happens for the emergence of low-energy Lorentz invariance, strong requirements have to be imposed on the underlying condensed matter model. We will show, within a simplified model, that the presence of a global symmetry alleviates the problems associated with Lorentz violation, allowing the presence of a long range potential, to which the analog matter fields (the quasiparticles) are coupled following a weaker form of equivalence principle.

We investigate the motion of neutral test particles in the gravitational field of a mass $M$ with charge $Q$ described by the Reissner-Nordström (RN) spacetime. We focus on the study of circular stable and unstable orbits around configurations describing either black holes or naked singularities. We show that at the classical radius, defined as $Q^2/M$, there exist orbits with zero angular momentum due to the presence of repulsive gravity. The analysis of the stability of circular orbits indicates that black holes are characterized by a continuous region of stability. In the case of naked singularities, the region of stability can split into two nonconnected regions inside which test particles move along stable circular orbits.

We show a constantly accelerated quark as a string solution of the Nambu-Goto action, which is embedded in the bulk background dual to the $\mathcal{N}=2$ supersymmetric confining Yang-Mills theory. The induced metric of the world sheet for this string solution has an event horizon specified by the fifth coordinate. By an extended Rindler transformation proposed by Xiao, we move to the comoving frame of the accelerated quark string. Then we find that this horizon is transferred to the event horizon of the bulk and the causal part of the accelerated quark is transformed to a static free quark in the Rindler coordinate. As a result, the confinement of the Minkowski vacuum is lost in the Rindler vacuum. This point is assured also by studying the potential between the quark and antiquark. However, the remnants of the original confining force are seen in various thermal quantities. We also discuss the consistency of our results and the claim that the Green’s functions will not be changed by the Rindler transformation.

We explore the cosmological consequences of the recently released Union2 sample of 557 type Ia supernovae. Combining this latest type Ia supernovae dataset with the cosmic microwave background anisotropy data from the Wilkinson Microwave Anisotropy Probe 7-yr observations and the baryon acoustic oscillation results from the Sloan Digital Sky Survey data release 7, we measure the dark energy density function $f(z)\equiv {\rho }_{\mathrm{de}}(z)/{\rho }_{\mathrm{de}}(0)$ as a free function of redshift. Two model-independent parametrization methods (the binned parametrization and the polynomial interpolation parametrization) are used in this paper. By using the ${\chi }^2$ statistic and the Bayesian information criterion, we find that the current observational data are still too limited to distinguish which parametrization method is better, and a simple model has the advantage in fitting observational data over a complicated model. Moreover, it is found that all these parametrizations demonstrate that the Union2 dataset is still consistent with a cosmological constant at $1\sigma$ confidence level. Therefore, the Union2 dataset is different from the Constitution type Ia supernovae dataset, which more favors a dynamical dark energy.

We revise and extend the stochastic gravitational lensing method (the sGL method) first introduced by Kainulainen and Marra [Phys. Rev. D 80, 123020 (2009)]. Here we include a realistic halo-mass function and density profiles to model the distribution of mass between and within galaxies, galaxy groups, and galaxy clusters. We also introduce a modeling of the filamentary large-scale structures and a method to embed halos into these structures. We show that the sGL method naturally reproduces the weak lensing results for the Millennium simulation. The strength of the sGL method is that a numerical code based on it can compute the lensing probability distribution function (PDF) for a given inhomogeneous model universe in a few seconds. This makes it a useful tool to study how lensing depends on cosmological parameters and its impact on observations. The sGL method can also be used to simulate the effect of a wide array of systematic biases on the observable lensing PDF. As an example we show how simple selection effects may reduce the variance of the observed PDF, which could possibly mask opposite effects from very large-scale structures. We also show how a survey like the Joint Dark Energy Mission could constrain the lensing PDF relative to a given cosmological model. The updated turboGL code is available at turboGL.org.