We continue a previous work on the comparison between the post-Newtonian (PN) approximation and the gravitational self-force (SF) analysis of circular orbits in a Schwarzschild background. We show that the numerical SF data contain physical information corresponding to extremely high PN approximations. We find that knowing analytically determined appropriate PN parameters helps tremendously in allowing the numerical data to be used to obtain higher order PN coefficients. Using standard PN theory we compute analytically the leading 4PN and the next-to-leading 5PN logarithmic terms in the conservative part of the dynamics of a compact binary system. The numerical perturbative SF results support well the analytic PN calculations through first order in the mass ratio, and are used to accurately measure the 4PN and 5PN nonlogarithmic coefficients in a particular gauge invariant observable. Furthermore we are able to give estimates of higher order contributions up to the 7PN level. We also confirm with high precision the value of the 3PN coefficient. This interplay between PN and SF efforts is important for the synthesis of template waveforms of extreme mass ratio inspirals to be analyzed by the space-based gravitational wave instrument LISA. Our work will also have an impact on efforts that combine numerical results in a quantitative analytical framework so as to generate complete inspiral waveforms for the ground-based detection of gravitational waves by instruments such as LIGO and Virgo.

We describe an efficient implementation of a coherent statistic for searches of continuous gravitational wave from neutron stars. The algorithm works by transforming the data taken by a gravitational wave detector from a moving Earth bound frame to one that sits at the Solar System barycenter. Many practical difficulties arise in the implementation of this algorithm, some of which have not been discussed previously. These difficulties include constraints of small computer memory, discreteness of the data, losses due to interpolation, and gaps in real data. This implementation is considerably more efficient than previous implementations of these kinds of searches on Laser Interferometer Gravitational Wave (LIGO) detector data. The speed-up factors range from 10, when applied to Einstein@Home, to about 2000 for targeted searches which integrate over months of data.

In this paper, the holographic dark energy models with the new infrared cutoff for both the flat case and the nonflat case are confronted with the combined constraints of current cosmological observations: type Ia supernovae, baryon acoustic oscillations, current cosmic microwave background, and the observational Hubble data. By utilizing the Markov chain Monte Carlo method, we obtain the best fit values of the parameters with $1\sigma$, $2\sigma$ errors in the flat model: ${\Omega }_b{h}^2={0.0233}_{-0.0009-0.0014}^{+0.0009+0.0013}$, $\alpha ={0.8502}_{-0.0875-0.1064}^{+0.0984+0.1299}$, $\beta ={0.4817}_{-0.0773-0.0955}^{+0.0842+0.1176}$, ${\Omega }_{\mathrm{de}0}={0.7287}_{-0.0294-0.0429}^{+0.0296+0.0432}$, ${\Omega }_{m0}={0.2713}_{-0.0296-0.0432}^{+0.0294+0.0429}$, $H_0={66.35}_{-2.14-3.07}^{+2.38+3.35}$. In the nonflat model, the constraint results are found in $1\sigma$, $2\sigma$ regions: ${\Omega }_b{h}^2={0.0228}_{-0.0010-0.0014}^{+0.0010+0.0014}$, ${\Omega }_k={0.0305}_{-0.0134-0.0176}^{+0.0092+0.0140}$, $\alpha ={0.8824}_{-0.1163-0.1378}^{+0.2180+0.2213}$, $\beta ={0.5016}_{-0.0871-0.1102}^{+0.0973+0.1247}$, ${\Omega }_{\mathrm{de}0}={0.6934}_{-0.0304-0.0413}^{+0.0364+0.0495}$, ${\Omega }_{m0}={0.2762}_{-0.0302-0.0412}^{+0.0278+0.0402}$, $H_0={70.20}_{-3.17-4.00}^{+3.03+3.58}$. In the best fit holographic dark energy models, the equation of state of dark energy and the deceleration parameter at present are characterized by $w_{\mathrm{de}0}=-1.1414\pm 0.0608$, $q_0=-0.7476\pm 0.0466$ (flat case) and $w_{\mathrm{de}0}=-1.0653\pm 0.0661$, $q_0=-0.6231\pm 0.0569$ (nonflat case). Compared to the $\Lambda \mathrm{CDM}$ model, it is found the current combined data sets do not favor the holographic dark energy model over the $\Lambda \mathrm{CDM}$ model.

Recent observations from PAMELA, FERMI, and ATIC point to a new source of high energy cosmic rays. If these signals are due to annihilating dark matter (DM), the annihilation cross section in the present day must be substantially larger than that necessary for thermal freeze-out in the early universe. A new force, mediated by a particle of mass $\mathcal{O}(100\mathrm{MeV})$, leading to a velocity-dependent annihilation cross section—a “Sommerfeld enhancement”—has been proposed as a possible explanation. We point out that such models necessarily increase the DM self-scattering cross section, and use observational bounds on the amount of DM-DM scattering allowed in various astrophysical systems to place constraints on the mass and couplings of the light mediator.

The detection of neutrinos from massive stellar collapses can teach us a great deal not only about source objects but also about microphysics working deep inside them. In this study we discuss quantitatively the possibility to extract information on the properties of dense and hot hadronic matter from neutrino signals coming out of black-hole-forming collapses of nonrotational massive stars. Based on our detailed numerical simulations we evaluate the event numbers for SuperKamiokande, with neutrino oscillations fully taken into account. We demonstrate that the event numbers from a Galactic event are large enough not only to detect but also to distinguish one hadronic equation of state from another by our statistical method, assuming the same progenitor model and nonrotation. This means that the massive stellar collapse can be a unique probe into hadron physics and will be a promising target of the nascent neutrino astronomy.

We identify a non-Hermitian chiral random matrix theory that corresponds to two-color QCD at high density. We show that the partition function of the random matrix theory coincides with the partition function of the finite-volume effective theory at high density, and that the Leutwyler-Smilga-type spectral sum rules of the random matrix theory are identical to those derived from the effective theory. The microscopic Dirac spectrum of the theory is governed by the BCS gap, rather than the conventional chiral condensate. We also show that with a different choice of a parameter the random matrix theory yields the effective partition function at low density.

We develop an approach to investigate the nonperturbative dynamics of quantum field theories, in which specific vacuum field fluctuations are treated as the low-energy dynamical degrees of freedom, while all other vacuum field configurations are explicitly integrated out from the path integral. We show how to compute the effective interaction between the vacuum field degrees of freedom both perturbatively (using stochastic perturbation theory) and fully nonperturbatively (using lattice field theory simulations). The present approach holds to all orders in the couplings and does not rely on the semiclassical approximation.

The discovery of some baryon-antibaryon resonances has led us to consider $3q$ $3\overline{q}$ systems as possible candidates. We predict their spectrum in the framework of a constituent model, where the chromomagnetic interaction plays the main role. The relevant parameters are fixed by the present knowledge of tetraquarks. The emerging scenario complies well with experiment; besides the description of the baryon-antibaryon resonances, we find evidence for new tetraquark states, namely, the $a_0(Y)$ in the hidden strangeness sector and the $Y(4140)$ and $X(4350)$ in the $cs\overline{cs}$ sector. A detailed account of the spectra and the decay channels is provided for future comparisons with data.

In models with an enhanced coupling of the Higgs boson to the bottom quark, the dominant production mechanism in hadronic collisions is often the partonic subprocess, $bg\to bH$. We derive the weak corrections to this process and show that they can be accurately approximated by an “improved Born approximation.” At the Tevatron, these corrections are negligible and are dwarfed by PDF and scale uncertainties for $M_H<200\mathrm{GeV}$. At the LHC, the weak corrections are small for $M_H<500\mathrm{GeV}$. For large Higgs boson masses, the corrections become significant and are $\sim 18\%$ for $M_H\sim 1\mathrm{TeV}$ at $\sqrt{s}=10\mathrm{TeV}$.

The generalized Chaplygin gas model is the prototype of a unified model of dark energy and dark matter (DM). It is characterized by equation-of-state parameters $A$ and $\alpha$. We use a statistical analysis of the 2dFGRS data to constrain these parameters. In particular, we find that very small (close to zero) and very large values ($\alpha \gg 1$) of the equation-of-state parameter $\alpha$ are preferred. To test the validity of this type of unification of the dark sector we admit the existence of a separate DM component in addition to the Chaplygin gas and calculate the probability distribution for the fractional contributions of both components to the total energy density. This analysis favors a model for which the Universe is nearly entirely made up of the separate DM component with an almost negligible Chaplygin gas part. This confirms the results of a previous Newtonian analysis.

We consider the Casimir effect for a sphere in front of a plane at finite temperature for scalar and electromagnetic fields and calculate the limiting cases. For small separation we compare the exact results with the corresponding ones obtained in proximity force approximation. For the scalar field with Dirichlet boundary conditions, the low temperature correction is of order $T^2$ like for parallel planes. For the electromagnetic field it is of order $T^4$. For high temperature we observe the usual picture that the leading order is given by the zeroth Matsubara frequency. The nonzero frequencies are exponentially suppressed except for the case of close separation.

A direct connection is proved between the non-Abelian Bianchi Identities (NABI’s) and the Abelian Bianchi identities for the ’t Hooft tensor. As a consequence, the existence of a nonzero magnetic current is related to the violation of the NABI’s and is a gauge-invariant property. The construction allows us to show that not all Abelian projections can be used to expose monopoles in lattice configurations: each field configuration with nonzero magnetic charge identifies its natural projection, up to gauge transformations which tend to unity at large distances. It is shown that the so-called maximal-Abelian gauge is a legitimate choice. It is also proven, starting from the NABI, that monopole condensation is a physical gauge-invariant phenomenon, independent of the choice of the Abelian projection.

In this paper we construct the Lagrangian and Hamiltonian formulations of $\mathcal{N}=4$ supersymmetric systems describing the motion of an isospin particle on a conformally flat four-manifold with $SO(4)$ isometry carrying the non-Abelian field of a Belavin-Polyakov-Shvarts-Tyupkin instanton. The conformal factor can be specified to yield various particular systems, such as superconformally invariant mechanics as well as a particle on the four-sphere, the pseudosphere, or on $\mathbb{R}\times {\mathbb{S}}^3$. The isospin degrees of freedom arise as bosonic components of an additional fermionic $\mathcal{N}=4$ supermultiplet, whose other components are rendered auxiliary by a nonlocal redefinition. Our on-shell component action coincides with the one recently proposed in [arXiv:0912.3289].

A charged parallel plate capacitor will create particle-antiparticle pairs by the Schwinger process and discharge over time. We consider the full quantum discharge process in $1+1$ dimensions including backreaction, when the electric field interacts with massless charged fermions. We recover oscillatory features in the electric field observed in a semiclassical analysis and find that the amplitude of the oscillations falls off as $t^{-1/2}$ and that stronger coupling implies slower decay. Remarkably, Ohm’s law applies to the vacuum and we evaluate the quantum electrical conductivity of the vacuum to be $2e/\sqrt{\pi }$, where $e$ is the fermionic charge. Similarities and differences with black hole evaporation are mentioned.

We construct an instanton describing the pair production of non-Kaluza-Klein bubbles of nothing in higher odd-dimensional de Sitter spaces. In addition to showing that higher-dimensional de Sitter spaces have a nonzero probability to become topologically nontrivial, this process provides direct evidence for the association of entropy with cosmological horizons as well as evidence that non-Kaluza-Klein bubbles of nothing are a necessary ingredient in string theory or any other consistent quantum theory of gravity in higher dimensions.

We formulate generalized uncertainty relations in a crystal-like universe—a “world crystal”—whose lattice spacing is of the order of Planck length. In the particular case when energies lie near the border of the Brillouin zone, i.e., for Planckian energies, the uncertainty relation for position and momenta does not pose any lower bound on involved uncertainties. We apply our results to micro black holes physics, where we derive a new mass-temperature relation for Schwarzschild micro black holes. In contrast to standard results based on Heisenberg and stringy uncertainty relations, our mass-temperature formula predicts both a finite Hawking’s temperature and a zero rest-mass remnant at the end of the micro black hole evaporation. We also briefly mention some connections of the world-crystal paradigm with ’t Hooft’s quantization and double special relativity.

It has been proposed that the apparent discrepancies between the inferred primordial abundances of ${}^6\mathrm{Li}$ and ${}^7\mathrm{Li}$ and the predictions of big bang nucleosynthesis (BBN) can be resolved by the existence of a negatively charged massive unstable supersymmetric particle ($X^{-}$) during the BBN epoch. Here, we present new BBN calculations with an $X^{-}$ particle utilizing an improved nuclear reaction network including captures of nuclei by the particle, nuclear reactions and $\beta$ decays of normal nuclei and nuclei bound to the $X^{-}$ particles ($X$ nuclei), and new reaction rates derived from recent rigorous quantum many-body dynamical calculations. We find that this is still a viable model to explain the observed ${}^6\mathrm{Li}$ and ${}^7\mathrm{Li}$ abundances. We also show that with the new rates the production of heavier nuclei is suppressed and there is no signature on abundances of nuclei heavier than Be in the $X^{-}$-particle catalyzed BBN model as has been previously proposed. We also consider the version of this model whereby the $X^{-}$ particle decays into the present cold dark matter. We analyze this paradigm in light of the recent constraints on the dark-matter mass deduced from the possible detected events in the CDMS-II experiment. We conclude that based upon the inferred range for the dark-matter mass, only $X^{-}$ decay via the weak interaction can achieve the desired ${}^7\mathrm{Li}$ destruction while also reproducing the observed ${}^6\mathrm{Li}$ abundance.

We consider the capture of inelastic dark matter in white dwarves by inelastic spin-independent scattering on nuclei. We show that if the dark matter annihilates to standard-model particles then, under the assumption of primordial globular cluster formation, the observation of cold white dwarves in the globular cluster M4 appears inconsistent with explanations of the observed DAMA/LIBRA annual modulation signal based on spin-independent inelastic dark matter scattering. Alternatively if the inelastic dark matter scenario were to be confirmed and it was found to annihilate to standard-model particles then this would imply a much lower dark matter density in the core of M4 than would be expected if it were to have formed in a dark matter halo. Finally we argue that cold white dwarves constitute a unique dark matter probe, complementary to other direct and indirect detection searches.

We constrain the cosmological density of cosmic string loops using two observational signatures—gravitational microlensing and the Kaiser-Stebbins effect. Photometry from RXTE and CoRoT space missions and pulsar timing from Parkes Pulsar Timing Array, Arecibo and Green Bank radio telescopes allow us to probe cosmic strings in a wide range of tensions $G\mu /c^2={10}^{-16}÷{10}^{-10}$. We find that pulsar timing data provide the most stringent constraints on the abundance of light strings at the level ${\Omega }_s\sim {10}^{-3}$. Future observational facilities such as the Square Kilometer Array will allow one to improve these constraints by orders of magnitude.

Certain anomalies at large angular scales in the cosmic microwave background (CMB) measured by WMAP have been suggested as possible evidence of breakdown of statistical isotropy (SI). SI violation of cosmological perturbations is a generic feature of ultralarge scale structure of the cosmos and breakdown of global symmetries. Most CMB photons free-stream to the present from the surface of last scattering. It is thus reasonable to expect statistical isotropy violation in the CMB photon distribution observed now to have originated from SI violation in the baryon-photon fluid at last scattering, in addition to anisotropy of the primordial power spectrum studied earlier in the literature. We consider the generalized anisotropic brightness distribution fluctuations, $\Delta (\overrightarrow{k},\widehat{n},\tau )$ (at conformal time $\tau$) in contrast to the SI case where it is simply a function of $|\overrightarrow{k}|$ and $\widehat{k}·\widehat{n}$. The brightness fluctuations expanded in bipolar spherical harmonic (BipoSH) series can then be written as ${\Delta }_{{\ell }_1{\ell }_2}^{LM}(k,\tau )$, where $L>0$ terms encode deviations from statistical isotropy. Violation of SI encoded in the present off-diagonal elements of the harmonic space correlation $⟨a_{\ell m}{a}_{{\ell }^{\prime }{m}^{\prime }}^{*}⟩$, equivalently, the BipoSH coefficients $A_{\ell {\ell }^{\prime }}^{LM}$, are then related to the generalized BipoSH brightness fluctuation terms at present. We study the evolution of ${\Delta }_{{\ell }_1{\ell }_2}^{LM}(k,\tau )$ from nonzero terms ${\Delta }_{{\ell }_3{\ell }_4}^{LM}(k,{\tau }_s)$ at last scattering, in the free-streaming regime. We show that the terms with given BipoSH multipole $LM$ evolve independently. Moreover, similar to the SI case, power at small spherical harmonic (SH) multipoles of ${\Delta }_{{\ell }_3{\ell }_4}^{LM}(k,{\tau }_s)$ at the last scattering is transferred to ${\Delta }_{{\ell }_1{\ell }_2}^{LM}(k,\tau )$ at larger SH multipoles. The structural similarity is more apparent in the asymptotic expression for large values of the final SH multipoles. This formalism allows an elegant identification of any SI violation observed today to a possible origin in SI violating physics present in the baryon-photon fluid. This is illustrated for the known result of SI violating angular correlations due to the presence of a homogeneous magnetic field in the baryon-photon fluid.