Gravitational waves contain tail effects which are due to the backscattering of linear waves in the curved space-time geometry around the source. In this paper we improve the knowledge and accuracy of the two-body inspiraling post-Newtonian (PN) dynamics and gravitational-wave signal by computing the spin-orbit terms induced by tail effects. Notably, we derive those terms at 3PN order in the gravitational-wave energy flux, and 2.5PN and 3PN orders in the wave polarizations. This is then used to derive the spin-orbit tail effects in the phasing through 3PN order. Our results can be employed to carry out more accurate comparisons with numerical-relativity simulations and to improve the accuracy of analytical templates aimed at describing the whole process of inspiral, merger, and ringdown.

As modified gravity theories, the four-dimensional metric $f(\mathcal{R})$ theories are cast into connection-dynamical formalism with real $su(2)$ connections as configuration variables. This formalism enables us to extend the nonperturbative loop quantization scheme of general relativity to any metric $f(\mathcal{R})$ theories. The quantum kinematical framework of $f(\mathcal{R})$ gravity is rigorously constructed, where the quantum dynamics can be launched. Both Hamiltonian constraint operator and master constraint operator for $f(\mathcal{R})$ theories are well defined. Our results show that the nonperturbative quantization procedure of loop quantum gravity are valid not only for general relativity but also for a rather general class of four-dimensional metric theories of gravity.

We determine the most general scalar field theories which have an action that depends on derivatives of order two or less, and have equations of motion that stay second order and lower on flat space-time. We show that those theories can all be obtained from linear combinations of Lagrangians made by multiplying a particular form of the Galileon Lagrangian by an arbitrary scalar function of the scalar field and its first derivatives. We also obtain curved space-time extensions of those theories which have second-order field equations for both the metric and the scalar field. This provides the most general extension, under the condition that field equations stay second order, of $k$-essence, Galileons, $k$-Mouflage as well as of the kinetically braided scalars. It also gives the most general action for a possible scalar classicalizer with second-order field equations. We discuss the relation between our construction and the Euler hierarchies of Fairlie et al. showing, in particular, that Euler hierarchies allow one to obtain the most general theory when the latter is shift symmetric. As a simple application of our formalism, we give the covariantized version of the conformal Galileon.

We study inflection point inflation using singularity theory, which relates degenerate critical points of functions to their local behavior. This approach illuminates universal features of small-field models and gives analytic control over parametrized families of scalar potentials near inflationary solutions. The behavior of the scalar potential is tied to the number of physical input parameters, which determines a set of universality classes. Within these classes, we obtain universal scaling relations for density perturbations and the scale of inflation. In specific models, we show that the scale of supersymmetry breaking also possesses scaling behavior. We illustrate this general structure with a specific example: the racetrack inflation model in type IIB string theory, with the inflaton being the real part of the Kähler modulus, and the input parameters being flux dependent quantities that appear in the four-dimensional $\mathcal{N}=1$ superpotential.

We discuss the possibility and the description of bound states between $B$ and ${\overline{B}}^{*}$ mesons. We argue that the existence of such a bound state can be deduced from (i) the weakly bound $X(3872)$ state, (ii) certain assumptions about the short-range dynamics of the $D{\overline{D}}^{*}$ system and (iii) heavy quark symmetry. From these assumptions the binding energy of the possible $B{\overline{B}}^{*}$ bound states is determined, first in a theory containing only contact interactions which serves as a straightforward illustration of the method, and then the effects of including the one-pion exchange potential are discussed. In this latter case three isoscalar states are predicted: a positive and negative C-parity ${}^{3}S_1-{}^{3}D_1$ state with a binding energy of 20 MeV and 6 MeV below threshold, respectively, and a positive C-parity ${}^{3}P_0$ shallow state located almost at the $B{\overline{B}}^{*}$ threshold. However, large uncertainties are generated as a consequence of the $1/m_Q$ corrections from heavy quark symmetry. Finally, the newly discovered isovector $Z_b(10610)$ state can be easily accommodated within the present framework by a minor modification of the short-range dynamics.

It is possible that there are additional vectorlike generations where the quarks have mass terms that do not originate from weak symmetry breaking, but the leptons only get mass through weak symmetry breaking. We discuss the impact that the new leptons have on Higgs boson decay branching ratios and on the range of allowed Higgs masses in such a model (with a single new vectorlike generation). We find that if the fourth generation leptons are too heavy to be produced in Higgs decay, then the new leptons reduce the branching ratio for $h\to \gamma \gamma$ to about 30% of its standard-model value. The dependence of this branching ratio on the new charged lepton masses is weak. Furthermore the expected Higgs production rate at the LHC is very near its standard-model value if the new quarks are much heavier than the weak scale. If the new quarks have masses near the cutoff for the theory, then for cutoffs greater than ${10}^{15}\mathrm{GeV}$, the new lepton masses cannot be much heavier than about 100 GeV and the Higgs mass must have a value around 175 GeV.

We consider the consequences of the presence of metric fluctuations upon the properties of a hydrogen atom. Particularly, we introduce these metric fluctuations in the corresponding effective Schrödinger equation and deduce the modifications that they entail upon the hyperfine structure related to a hydrogen atom. We will find the change that these effects imply for the ground state energy of the system and obtain a bound for its size comparing our theoretical predictions against the experimental uncertainty reported in the literature. In addition, we analyze the corresponding Lamb shift effect emerging from these fluctuations of spacetime. Once again, we will set a bound to these oscillations resorting to the current experimental outcomes.

Hidden sector photons are a weakly interacting slim particle arising from an additional U(1) gauge symmetry predicted by many standard model extensions. We present and demonstrate a new experimental method using a single microwave cavity to search for hidden sector photons. Only photons with a great enough energy are able to oscillate into hidden sector photons of a particular mass. If our cavity is driven on resonance and tuned over the corresponding threshold frequency, an observed drop in the circulating power signifies the creation of hidden sector photons. This approach avoids the problems of microwave leakage and frequency matching inherent in photon regeneration techniques.

The electroweak $\mathcal{O}(\alpha )$ radiative corrections to the decay of the heavy $CP$-even minimal supersymmetric standard model Higgs boson to weak gauge bosons are presented. Because of the suppression of the tree-level $H^{0}WW/H^{0}ZZ$ coupling, the electroweak contributions to the partial decay width are significant. Although the effective Born decay width can be rather small for certain $M_{A^0}$ values (especially for large $\tan \beta$), the corrected partial widths at different values of $M_{A^0}$ are of comparable size.

The specific shape of the squark, slepton and gaugino mass spectra, if measured with sufficient accuracy, can provide invaluable information not only about the dynamics underpinning their origin at some very high scale such as the unification scale $M_G$, but also about the intermediate scale physics encountered throughout their renormalization group equations evolution down to the energy scale accessible for the LHC. In this work, we study general features of the TeV scale soft supersymmetry breaking parameters stemming from a generic mSugra configuration within certain classes of supersymmetry $SO(10)$ GUTs with different intermediate symmetries below $M_G$. We show that particular combinations of soft masses show characteristic deviations from the mSugra limit in different models and thus, potentially, allow to distinguish between these, even if the new intermediate scales are outside the energy range probed at accelerators. We also compare our results to those obtained for the three minimal seesaw models with mSugra boundary conditions and discuss the main differences between those and our $SO(10)$ based models.

We construct a new $\mathcal{N}=4$ supersymmetric mechanics describing the motion of a particle over a $C{P}^n$ manifold in $U(n)$ background gauge fields.

We construct supersymmetric $k$ field theories (i.e., theories with a nonstandard kinetic term) in $1+1$ and $2+1$ dimensions such that the bosonic sector just consists of a nonstandard kinetic term plus a potential. Further, we study the possibility of topological defect formation in these supersymmetric models. Finally, we consider more general supersymmetric $k$ field theories where, again, topological defects exist in some cases.

All microscopic correlation functions of the spectrum of the Hermitian Wilson Dirac operator with any number of flavors with equal masses are computed. In particular, we give explicit results for the spectral density in the physical case with two light quark flavors. The results include the leading effect in the discretization error and are given for fixed index of the Wilson Dirac operator. They have been obtained starting from chiral Lagrangians for the generating function of the Dirac spectrum. Microscopic correlation functions of the real eigenvalues of the Wilson Dirac operator are computed following the same approach.

We consider a theory of scalar and spinor fields, interacting through Yukawa and ${\varphi }^4$ interactions, with Lorentz-violating operators included in the Lagrangian. We compute the leading quantum corrections in this theory. The renormalizability of the theory is explicitly shown up to one-loop order. In the pure scalar sector, the calculations can be generalized to higher orders and to include finite terms, because the theory can be solved in terms of its Lorentz-invariant version.

We derive the effects of a nonzero cosmological constant $\Lambda$ on gravitational wave propagation in the linearized approximation of general relativity. In this approximation, we consider the situation where the metric can be written as $g_{\mu \nu }={\eta }_{\mu \nu }+h_{\mu \nu }^{\Lambda }+h_{\mu \nu }^W$, $h_{\mu \nu }^{\Lambda ,W}\ll 1$, where $h_{\mu \nu }^{\Lambda }$ is the background perturbation and $h_{\mu \nu }^W$ is a modification interpretable as a gravitational wave. For $\Lambda \ne 0$, this linearization of Einstein equations is self-consistent only in certain coordinate systems. The cosmological Friedmann-Robertson-Walker coordinates do not belong to this class and the derived linearized solutions have to be reinterpreted in a coordinate system that is homogeneous and isotropic to make contact with observations. Plane waves in the linear theory acquire modifications of order $\sqrt{\Lambda }$, both in the amplitude and the phase, when considered in Friedmann-Robertson-Walker coordinates. In the linearization process for $h_{\mu \nu }$, we have also included terms of order $\mathcal{O}(\Lambda h_{\mu \nu })$. For the background perturbation $h_{\mu \nu }^{\Lambda }$, the difference is very small, but when the term $h_{\mu \nu }^W\Lambda$ is retained the equations of motion can be interpreted as describing massive spin-2 particles. However, the extra degrees of freedom can be approximately gauged away, coupling to matter sources with a strength proportional to the cosmological constant itself. Finally, we discuss the viability of detecting the modifications caused by the cosmological constant on the amplitude and phase of gravitational waves. In some cases, the distortion with respect to gravitational waves propagating in Minkowski space-time is considerable. The effect of $\Lambda$ could have a detectable impact on pulsar timing arrays.

Extending the analysis of J. Meyers and N. Sivanandam [Phys. Rev. D 83, 103517 (2011)] beyond the bispectrum, we explore the superhorizon generation of local non-Gaussianities and their subsequent approach to adiabaticity. Working with a class of two field models of inflation with potentials amenable to treatment with the $\delta N$ formalism, we find that, as is the case for $f_{\mathrm{NL}}^{\mathrm{local}}$, the local trispectrum parameters ${\tau }_{\mathrm{NL}}$ and $g_{\mathrm{NL}}$ are exponentially driven toward values which are slow-roll suppressed if the fluctuations are driven into an adiabatic mode by a phase of effectively single field inflation. We argue that general considerations should ensure that a similar behavior will hold for the local forms of higher point correlations as well.

We compute the parametrized post-Newtonian (PPN), $\gamma$, for scalar tensor gravity theory when the action functional for the scalar field is a nonstandard one, namely, the Dirac-Born-Infeld type action, used in the literature for a tachyon field. We investigate two different cases (linear and conformal couplings) when the scalar field is nonminimally coupled to gravity via the scalar curvature. We find that the PPN parameter $\gamma$, which measures the amount of space curvature per unit rest mass, becomes a function of the effective mass of the scalar field. Using this PPN parameter, we calculate the time delay $\Delta \tau$ for the signal to travel the round-trip distance between a ground-based antenna and a reflector placed in a spacecraft which is produced due to the gravitational field of the Sun. We use this $\Delta \tau$ to compare our result with that obtained by the Cassini mission and derive the constraints on the model parameters.

We examine the thermal evolution of a sequence of compact objects containing low-mass hadronic and high-mass quark-hadronic stars constructed from a microscopically motivated equation of state. The dependence of the cooling tracks in the temperature versus age plane is studied on the variations of the gaplessness parameter (the ratio of the pairing gap for red-green quarks to the electron chemical potential) and the magnitude of blue quark gap. The pairing in the red-green channel is modeled assuming an inhomogeneous superconducting phase to avoid tachionic instabilities and anomalies in the specific heat; the blue colored condensate is modeled as a Bardeen-Cooper-Schrieffer (BCS)-type color superconductor. We find that massive stars containing quark matter cool faster in the neutrino-cooling era if one of the colors (blue) is unpaired and/or the remaining colors (red-green) are paired in a inhomogeneous gapless superconducting state. The cooling curves show significant variations along the sequence, as the mass (or the central density) of the models is varied. This feature provides a handle for fine-tuning the models to fit the data on the surface temperatures of same-age neutron stars. In the late-time photon cooling era we observe inversion in the temperature arrangement of models, i.e., stars experiencing fast neutrino cooling are asymptotically hotter than their slowly cooling counterparts.

A class of Bianchi type II expanding solutions in a Lorentz Chern-Simons theory has been known to break the cosmic no-hair theorem. These solutions do not approach the late-time de Sitter Universe. We will show that there are two independent solutions classified by the parameter $p$ for each given cosmological constant $\Lambda$. One of them is in the small-$p$ phase; the other solution is in the large-$p$ phase. It can be shown that an unstable mode always exists for the solution in its small-$p$ phase that comes with smaller energy $T_{00}$ and $T_{00}+T/2$. The result indicates that the large-$p$ phase is unlikely to be stable from an observation of a modified version of Wald’s theorem.