We study direct and indirect detection possibilities of neutralino dark matter produced nonthermally by, e.g., the decay of long-lived particles, as is easily implemented in the case of anomaly or mirage-mediation models. In this scenario, large self-annihilation cross sections are required to account for the present dark matter abundance, and it leads to significant enhancement of the gamma-ray signature from the galactic center and the positron flux from the dark matter annihilation. It is found that GLAST and PAMELA will find the signal or give tight constraints on such nonthermal production scenarios of neutralino dark matter.

I present an exhaustive numerical investigation of the optical caustics in gravitational lensing by a spinning black hole for an observer at infinity. Besides the primary caustic, I examine higher order caustics, formed by photons performing one or several loops around the black hole. My investigation covers the whole parameter space, including the black hole spin, its inclination with respect to the line of sight, the source distance, and the caustic order. By comparing my results with the available analytical approximations, I find perfect agreement in their respective domains of validity. I then prove that all caustics maintain their shape (a tube with astroidal cross section) in the entire parameter space without suffering any transitions to different caustic shapes. For nearly extremal spin, however, higher order caustics grow so large that their cross sections at fixed radii wind several times around the black hole. As a consequence, for each caustic order, the number of images ranges from 2 to $2(n+1)$, where $n$ is the number of loops spanned by the caustic. As for the critical curves, I note that for high values of the spin they develop a small dip on the side corresponding to prograde orbits.

The large extra dimension model is a promising way to solve the hierarchy problem of the standard model. In this paper we investigate the associated production of $t\overline{t}H$ at the LHC within the large extra dimension model. We present the dependence of the cross section on the fundamental scale ${\mathrm{M}}_{\mathrm{S}}$, and also give the $p_T$ distribution of the final state particles. The large extra dimension effects enhance the cross section significantly. We also give the discovery limits of ${\mathrm{M}}_{\mathrm{S}}$ on the process $pp\to t\overline{t}H$, which are 14.295, 9.595, 6.93, and 1.235 TeV when the extra dimensions are 3, 4, 5, and 6, respectively.

Kaon condensation may play an important role in the structure of hadronic matter at densities greater than that of nuclear matter, as exist in the interior of neutron stars. We present the results of the first lattice QCD investigation of kaon condensation obtained by studying systems containing up to 12 negatively charged kaons. Surprisingly, the properties of the condensate that we calculate are remarkably well reproduced by leading order chiral perturbation theory. In our analysis, we also determine the three-kaon interaction from the multi-kaon systems and update our results for pion condensates.

We use lattice QCD simulations, with MILC gluon configurations and HISQ $c$-quark propagators, to make very precise determinations of moments of charm-quark pseudoscalar, vector and axial-vector correlators. These moments are combined with new four-loop results from continuum perturbation theory to obtain several new determinations of the $\overline{\mathrm{MS}}$ mass of the charm quark and of the $\overline{\mathrm{MS}}$ coupling. We find $m_c(3\mathrm{GeV})=0.986(10)\mathrm{GeV}$, or, equivalently, $m_c(m_c)=1.268(9)\mathrm{GeV}$, both for $n_f=4$ flavors; and ${\alpha }_{\overline{\mathrm{MS}}}(3\mathrm{GeV},n_f=4)=0.251(6)$, or, equivalently, ${\alpha }_{\overline{\mathrm{MS}}}(M_Z,n_f=5)=0.1174(12)$. The new mass agrees well with results from continuum analyses of the vector correlator using experimental data for $e^{+}{e}^{-}$ annihilation (instead of using lattice QCD simulations). These lattice and continuum results are the most accurate determinations to date of this mass. Ours is also one of the most accurate determinations of the QCD coupling by any method.

We present a measurement of the inclusive jet cross section in $p\overline{p}$ collisions at $\sqrt{s}=1.96\mathrm{TeV}$ based on data collected by the CDF II detector with an integrated luminosity of $1.13{\mathrm{fb}}^{-1}$. The measurement was made using the cone-based midpoint jet clustering algorithm in the rapidity region of $|y|<2.1$. The results are consistent with next-to-leading-order perturbative QCD predictions based on recent parton distribution functions (PDFs), and are expected to provide increased precision in PDFs at high parton momentum fraction $x$. The results are also compared to the recent inclusive jet cross section measurement using the $k_T$ jet clustering algorithm, and we find that the ratio of the cross sections measured with the two algorithms is in agreement with theoretical expectations over a large range of jet transverse momentum and rapidity.

The propagators of the Faddeev-Popov (FP) ghosts for Yang-Mills theories and perturbative quantum gravity in the covariant gauge are infrared (IR) divergent in de Sitter spacetime. We point out, however, that the modes responsible for these divergences will not contribute to loop diagrams in computations of time-ordered products in either Yang-Mills theories or perturbative quantum gravity. Therefore, we propose that the IR-divergent FP-ghost propagator should be regularized by a small mass term that is sent to zero in the end of any perturbative calculations. This proposal is equivalent to using the effective FP-ghost propagators, which we present in an explicit form, obtained by removing the modes responsible for the IR divergences. We also make some comments on the corresponding propagators in anti-de Sitter spacetime.

We propose a generalization of the Bagger-Lambert-Gustavsson action as a candidate for the description of an arbitrary number of M2-branes. The action is formulated in terms of $\mathcal{N}=2$ superfields in three dimensions and corresponds to an extension of the usual superfield formulation of Chern-Simons matter theories. Demanding gauge invariance of the resulting theory does not imply the total antisymmetry of the underlying 3-Lie algebra structure constants. We relax this condition and propose a class of examples for these generalized 3-Lie algebras. We also discuss various associated ordinary Lie algebras.

We calculate the entropy of adiabatic perturbations associated with a truncation of the hierarchy of Green functions at the first nontrivial level, i.e. in a self-consistent Gaussian approximation. We derive the equation governing the entropy growth and discuss its phenomenology. It is parametrized by two model-dependent kernels. We then examine two particular inflationary models, one with isocurvature perturbations, the other with corrections due to loops of matter fields. In the first model the entropy grows rapidly, while in the second the state remains pure (at one loop).

We propose an operational definition of the entropy of cosmological perturbations based on a truncation of the hierarchy of Green functions. The value of the entropy is unambiguous despite gauge invariance and the renormalization procedure. At the first level of truncation, the reduced density matrices are Gaussian and the entropy is the only intrinsic quantity. In this case, the quantum-to-classical transition concerns the entanglement of modes of opposite wave vectors, and the threshold of classicality is that of separability. The relations to other criteria of classicality are established. We explain why, during inflation, most of these criteria are not intrinsic. We complete our analysis by showing that all reduced density matrices can be written as statistical mixtures of minimal states, the squeezed properties of which are less constrained as the entropy increases. Pointer states therefore appear not to be relevant to the discussion. The entropy is calculated for various models in Paper II.

The phase diagram of the massive chiral Gross-Neveu model (the massive Nambu–Jona-Lasinio model in $1+1$ dimensions) is constructed. In the large $N$ limit, the Hartree-Fock approach can be used. We find numerically a chiral crystal phase separated from a massive Fermi gas phase by a 1st order transition. Using perturbation theory, we also construct the critical sheet where the homogeneous phase becomes unstable in a 2nd order transition. A tricritical curve is located. The phase diagram is mapped out as a function of fermion mass, chemical potential and temperature, and compared with the one of the discrete chiral Gross-Neveu model. As a by-product, we illustrate the crystal structure of matter at zero temperature for various densities and fermion masses.

We consider the supersymmetry algebras of the maximal supergravities in 10 and 11 dimensions. We construct expressions from which the topological charge structure of the algebras can be determined in supersymmetric curved backgrounds. These are interpreted as the topological charges of the $1/2$-BPS states that are found in the theories. We consider charges for all the M-, NS- and D-branes as well as the Kaluza-Klein monopoles. We also show that the dimensional reduction relations between the 11-dimensional and IIA charges, and T-duality relations of the IIA and IIB charges, match those found for the branes themselves. Finally we consider the massive versions of the IIA and 11-dimensional theories and find that the expressions for the charges, with a slight modification, are still valid in those instances.

In this work, some interesting details about quantum Minkowski space and quantum Lorentz group structures are revealed. The task is accomplished by generalizing an approach adopted in a previous work where quantum rotation group and quantum Euclidean space structures have been investigated. The generalized method is based on a mapping relating the $q$-spinors (precisely the tensor product of dotted and undotted fondamental $q$-spinors) to Minkowski $q$-vectors. As a result of this mapping, the quantum analog of Minkowski space is constructed (with a definite metric). Also, the matrix representation of the quantum Lorentz group is determined together with its corresponding $q$-deformed orthogonality relation.

We propose a method to study and constrain modified gravity theories for dark matter using CMB temperature anisotropies and polarization. We assume that the theories considered here have already passed the matter power-spectrum test of large-scale structure. With this requirement met, we show that a modified gravity theory can be specified by parametrizing the time evolution of its dark-matter density contrast, which is completely controlled by the dark-matter stress history. We calculate how the stress history with a given parametrization affects the CMB observables, and a qualitative discussion of the physical effects involved is supplemented with numerical examples. It is found that, in general, alternative gravity theories can be efficiently constrained by the CMB temperature and polarization spectra. There exist, however, special cases where modified gravity cannot be distinguished from the CDM model even by using both CMB and matter power spectrum observations, nor can they be efficiently restricted by other observables in perturbed cosmologies. Our results show how the stress properties of dark matter, which determine the evolutions of both density perturbations and the gravitational potential, can be effectively investigated using just the general conservation equations and without assuming any specific theoretical gravitational theory within a wide class.

The dynamical generation of a four-dimensional classical universe from nothing but fundamental quantum excitations at the Planck scale is a long-standing challenge to theoretical physicists. A candidate theory of quantum gravity which achieves this goal without invoking exotic ingredients or excessive fine-tuning is based on the nonperturbative and background-independent technique of causal dynamical triangulations. We demonstrate in detail how in this approach a macroscopic de Sitter universe, accompanied by small quantum fluctuations, emerges from the full gravitational path integral, and how the effective action determining its dynamics can be reconstructed uniquely from Monte Carlo data. We also provide evidence that it may be possible to penetrate to the sub-Planckian regime, where the Planck length is large compared to the lattice spacing of the underlying regularization of geometry.

Single field inflationary models with a nonminimal kinetic term (also called $k$-inflationary models) can be characterized by the so-called sound flow functions, which complete the usual Hubble flow hierarchy. These parameters appear in the primordial power spectra of cosmological perturbations at leading order and, therefore, affect the resulting cosmic microwave background anisotropies. Using the fifth year Wilkinson Microwave Anisotropy Probe (WMAP5) data, we derive the marginalized posterior probability distributions for both the sound and Hubble flow parameters. In contrast to the standard situation, these parameters remain separately unbounded, and notably there is no longer any upper limit on ${ϵ}_1$, the first Hubble flow function. Only special combinations of these parameters, corresponding to the spectral index and tensor-to-scalar ratio observables, are actually constrained by the data. The energy scale of $k$-inflation is nevertheless limited from above to $H_{\inf }\le 6\times {10}^{-6}{m}_{\mathrm{Pl}}$ at two-sigma level. Moreover, for the subclass of Dirac-Born-Infeld models, by considering the non-Gaussianity bounds on the sound speed, we find a weak limit ${ϵ}_1<0.08$ at 95% confidence level.

Using gamma-ray data from observations of the Milky Way, Andromeda (M31), and the cosmic background, we calculate conservative upper limits on the dark matter self-annihilation cross section to monoenergetic gamma rays, $⟨{\sigma }_{A}v{⟩}_{\gamma \gamma }$, over a wide range of dark matter masses. (In fact, over most of this range, our results are unchanged if one considers just the branching ratio to gamma rays with energies within a factor of a few of the endpoint at the dark matter mass.) If the final-state branching ratio to gamma rays, $\mathrm{Br}(\gamma \gamma )$, were known, then $⟨{\sigma }_{A}v{⟩}_{\gamma \gamma }/\mathrm{Br}(\gamma \gamma )$ would define an upper limit on the total cross section; we conservatively assume $\mathrm{Br}(\gamma \gamma )\gtrsim {10}^{-4}$. An upper limit on the total cross section can also be derived by considering the appearance rates of any standard model particles; in practice, this limit is defined by neutrinos, which are the least detectable. For intermediate dark matter masses, gamma-ray-based and neutrino-based upper limits on the total cross section are comparable, while the gamma-ray limit is stronger for small masses and the neutrino limit is stronger for large masses. We comment on how these results depend on the assumptions about astrophysical inputs and annihilation final states, and how GLAST and other gamma-ray experiments can improve upon them.

Several mechanisms exist for generating a stochastic background of gravitational waves in the period following inflation. These mechanisms are generally classical in nature, with the gravitational waves being produced from inhomogeneities in the fields that populate the early Universe and not quantum fluctuations. The resulting stochastic background could be accessible to next generation gravitational wave detectors. We develop a framework for computing such a background analytically and computationally. As an application of our framework, we consider the stochastic background of gravitational waves generated in a simple model of preheating.

Recently a Born-Infeld action for dark energy and dark matter that uses additional affine connections was proposed. At the background level, it was shown that the new proposal can mimic the standard cosmological evolution. In Bianchi cosmologies, contrary to the scalar field approach (e.g., Chaplygin gas), the new approach leads to anisotropic pressure, raising the issues of stability of the isotropic solution under anisotropic perturbations and, being stable, how the anisotropies evolve. In this work, the Eddington-Born-Infeld proposal is extended to a Bianchi type I scenario and residual post-inflationary anisotropies are shown to decay in time. Moreover, it is shown that the shears decay following a damped oscillatory pattern, instead of the standard exponential-like decay. Allowing for some fine-tuning on the initial conditions, standard theoretical bounds on the shears can be avoided.