The four-dimensional Gödel spacetime is known to have the structure $M_3\times \Re$. It is also known that the three-dimensional factor $M_3$ is an exact solution of three-dimensional gravity coupled to a Maxwell-Chern-Simons theory. We build in this paper a $\mathcal{N}=2$ supergravity extension for this action and prove that the Gödel background preserves half of all supersymmetries.

We study 2-field inflation models based on the “large-volume” flux compactification of type IIB string theory. The role of the inflaton is played by a Kähler modulus $\tau$ corresponding to a 4-cycle volume and its axionic partner $\theta$. The freedom associated with the choice of Calabi-Yau manifold and the nonperturbative effects defining the potential $V(\tau ,\theta )$ and kinetic parameters of the moduli brings an unavoidable statistical element to theory prior probabilities within the low-energy landscape. The further randomness of $(\tau ,\theta )$ initial conditions allows for a large ensemble of trajectories. Features in the ensemble of histories include “roulette trajectories,” with long-lasting inflations in the direction of the rolling axion, enhanced in the number of e-foldings over those restricted to lie in the $\tau$-trough. Asymptotic flatness of the potential makes possible an eternal stochastic self-reproducing inflation. A wide variety of potentials and inflaton trajectories agree with the cosmic microwave background and large scale structure data. In particular, the observed scalar tilt with weak or no running can be achieved in spite of a nearly critical de Sitter deceleration parameter and consequently a low gravity wave power relative to the scalar curvature power.

We calculate the power spectrum of curvature perturbations when the inflaton field is rolling over the top of a local maximum of a potential. We show that the evolution of the field can be decomposed into a late-time attractor, which is identified as the slow roll solution, plus a rapidly decaying non-slow roll solution, corresponding to the field rolling “up the hill” to the maximum of the potential. The exponentially decaying transient solution can map to an observationally relevant range of scales because the Universe is also expanding exponentially. We consider the two branches separately and we find that they are related through a simple transformation of the slow roll parameter $\eta$ and they predict identical power spectra. We generalize this approach to the case where the inflaton field is described by both branches simultaneously and find that the mode equation can be solved exactly at all times. Even though the slow roll parameter $\eta$ is evolving rapidly during the transition from the transient solution to the late-time attractor solution, the resultant power spectrum is an exact power-law spectrum. Such solutions may be useful for model building on the string landscape.

Expression for second post-Newtonian level gravitational deflection angle of massive particles is obtained in a model independent framework. Comparison of theoretical values with the observationally constructed values of post-Newtonian parameters for massive particles offers the future possibility of testing at that level competing gravitational theories as well as the equivalence principle. Advantage of studying gravitational deflection of massive particles over that of massless particles in testing gravity is discussed.

We investigate the one-loop contributions to $S$ and $T$ oblique parameters in gauge-Higgs unification. We show that these parameters are finite in five dimensional space-time, but are divergent in more than five dimensions. Remarkably, however, we find that a particular linear combination of $S$ and $T$ parameters, $S-4\cos {\theta }_{W}T$, becomes finite for six dimensional space-time, though each of these parameters are divergent. This is because, in the gauge-Higgs unification scenario, the operators relevant for $S$ and $T$ parameters are not independent, but are included in a unique higher dimensional gauge invariant operator. Thus the predictable linear combination is model independent, irrespective of the detail of the matter content.

We illustrate the utility of jet-mass distributions as probes of new physics at the LHC, focusing on a heavy vector-quark doublet that mixes with the top as a concrete example. For 1 TeV vector-quark masses, we find that signals with greater than $5\sigma$ significance can be achieved after $100{\mathrm{fb}}^{-1}$. More generally, jet-mass distributions have the potential to provide signals for heavy states that produce highly boosted weak gauge bosons and/or top quarks.

We calculate all the branching ratios and direct $CP$ violations of $B\to PV$ decays in the most general two-Higgs-doublet model with spontaneous $CP$ violation (type III 2HDM). As the model has rich $CP$-violating sources, it is shown that the new physics effects to direct $CP$ violations and branching ratios in some channels can be significant when adopting the generalized factorization approach to evaluate the hadronic matrix elements, which provides good signals for probing new physics beyond the SM in the future $B$ experiments.

A new class of enhanced nonperturbative corrections to the inclusive $\overline{B}\to X_s\gamma$ decay rate is identified, which contribute first at order $\Lambda /m_b$ in the heavy-quark expansion and cannot be described using a local operator product expansion. Instead, these effects are described in terms of hadronic matrix elements of nonlocal operators with component fields separated by lightlike distances. They contribute to the high-energy part of the photon-energy spectrum but do not reduce to local operators when an integral over energy is taken to obtain the total inclusive decay rate. The dominant corrections depend on the flavor of the $B$-meson spectator quark and are described by trilocal four-quark operators. Their contribution is estimated using the vacuum insertion approximation. The corresponding uncertainty in the total decay rate is found to be at the few percent level. This new effect accounts for the leading contribution to the rate difference between $B^{-}$ and ${\overline{B}}^0$ mesons.

This paper is devoted to the study of some aspects of the instability of two flavor color-superconductive quark matter. We find that, beside color condensates, the Goldstone boson related to the breaking of $U(1{)}_A$ suffers from a velocity instability. We relate this wrong sign problem, which implies the existence of a Goldstone current in the ground state or of gluonic condensation, to the negative squared Meissner mass of the 8th gluon in the gapless two flavor color superconductor (g2SC) phase. Moreover we investigate the Meissner masses of the gluons and the squared velocity of the Goldstone in the multiple-plane-wave Larkin-Ovchinnikov-Fulde-Ferrel (LOFF) states, arguing that in such phases both the chromomagnetic instability and the velocity instability are most probably removed. We also do not expect Higgs instability in such multiple-plane-wave LOFF, at least when one considers fluctuations with small momenta. The true vacuum of gapless two flavor superconductors is thus expected to be a multiple-plane-wave LOFF state.

We investigate and compute spectral sums of the Wilson lattice Dirac operator for quenched $SU(3)$ gauge theory. It is demonstrated that there exist sums which serve as order parameters for the confinement-deconfinement phase transition and get their main contribution from the IR end of the spectrum. They are approximately proportional to the Polyakov loop. In contrast to earlier studied spectral sums, some of them are expected to have a well-defined continuum limit.

We investigate deviation from the tribimaximal mixing in the case of ultrahigh energy neutrino using the ICECUBE detector. We consider the ratio of the number of muon tracks to the shower generated due to eletrons and hadrons. Our analysis shows that for tribimaximal mixing the ratio comes out around 4.05. Keeping ${\theta }_{12}$ and ${\theta }_{23}$ fixed at tribimaximal value, we have varied the angle ${\theta }_{13}=3°$, 6°, 9° and the value of the ratio gradually decreases. The variation of ratio lies within 8% to 18% from the tribimaximal mixing value and it is very difficult to detect such a small variation by the ICECUBE detector.

We show explicitly that the sum over punctures for the three-times derivative for the Penner free energy , given by D. A. Johnston [], is not correct. As a consequence, Eq. (21), the differentiated version for the renormalization group (RG) equation, is wrong. Also, his conclusion that the differentiated version of the RG equation for the three-times derivative of the free energy can be obtained from the higher genus RG equation cannot be true. Finally, the differentiated version of the RG equation is extended to any derivative of the free energy .

We present a new mechanism, the $S$-Track, to stabilize the volume modulus $S$ in heterotic M-theory flux compactifications along with the orbifold size $T$ besides complex structure and vector bundle moduli stabilization. The key dynamical ingredient which makes the volume modulus stabilization possible, is M5 instantons arising from M5 branes wrapping the whole Calabi-Yau slice. These are natural in heterotic M theory where the warping shrinks the Calabi-Yau volume along ${\mathbf{S}}^1/{\mathbf{Z}}_2$. Combined with $H$ flux, open M2 instantons, and hidden sector gaugino condensation it leads to a superpotential $W$ which stabilizes $S$ similar to a racetrack but without the need for multi-gaugino condensation. Moreover, $W$ contains two competing nonperturbative effects which stabilize $T$. We analyze the potential and superpotentials to show that it leads to heterotic de Sitter vacua with broken supersymmetry through nonvanishing F terms.

A warped space model with a constant boundary superpotential has been an efficient model both to break supersymmetry and to stabilize the radius, when a hypermultiplet, a compensator, and a radion multiplet are taken into account. In such a model of radius stabilization, the radion and moduli masses, the gravitino mass, and the induced soft masses are studied. We find that a lighter physical mode composed of the radion and the moduli can have mass of the order of a TeV and that the gravitino mass can be of the order of ${10}^7\mathrm{GeV}$. It is also shown that soft mass induced by the anomaly mediation can be of the order of 100 GeV and can be dominant compared to that mediated by bulk fields. Localized $F$-terms and $D$-terms are discussed as candidates for canceling the cosmological constant. We find that there is no flavor changing neutral current problem in a wide range of parameters.

We study the effect of neutrino trapping in newborn quark stars within a three-flavor Nambu–Jona-Lasinio model with self-consistently calculated quark masses. The phase diagrams and equations of state for charge neutral quark matter in $\beta$ equilibrium are presented, with and without trapped neutrinos. The compact star sequences for different neutrino untrapping scenarios are investigated and the energy release due to neutrino untrapping is found to be of the order of ${10}^{53}\mathrm{erg}$. We find that hot quark stars characterized, e.g., by an entropy per baryon of 1–2 and a lepton fraction of 0.4, as models for the cores of newborn protoneutron stars, are in the two-flavor color superconducting state. High temperatures and/or neutrino chemical potentials disfavor configurations with a color-flavor-locked phase. Stable quark star solutions with color-flavor-locked cores exist only at low temperatures and neutrino chemical potentials.

Using the anti–de Sitter/conformal field theories (AdS/CFT) correspondence, we address the question of how to measure complicated space-time metrics using gauge theory probes. In particular, we consider the case of the $1/2$ Bogomol’nyi-Prasad-Sommerfield geometries of type IIB supergravity. These geometries are classified by certain droplets in a two-dimensional spacelike hypersurface. We show how to reconstruct the full metric inside these droplets using the one-loop $\mathcal{N}=4$ super Yang-Mills theory dilatation operator. This is done by considering long operators in the $SU(2)$ sector, which are dual to fast rotating strings on the droplets. We develop new powerful techniques for large $N$ complex matrix models that allow us to construct the Hamiltonian for these strings. We find that the Hamiltonian can be mapped to a dynamical spin chain. That is, the length of the chain is not fixed. Moreover, all of these spin chains can be explicitly constructed using an interesting algebra which is derived from the matrix model. Our techniques work for general droplet configurations. As an example, we study a single elliptical droplet and the hypotrochoid.

To a domain wall or string object, Noether charge and topological spatial objects can be attracted, forming a composite Bogomolny-Prasad-Sommerfield (BPS) object. We consider two field theories and derive a new BPS bound on composite linear solitons involving multiple charges. Among the BPS objects “supertubes” appear when the wall or string tension is canceled by the bound energy, and could take an arbitrary closed curve. In our theories, supertubes manifest as Chern-Simons solitons, dyonic instantons, charged semilocal vortices, and dyonic instantons on the vortex flux sheet.

In an earlier paper, we obtained exact solutions of the Wheeler-DeWitt equation for the Lemaître-Tolman-Bondi model of gravitational collapse, employing a lattice regularization. In this paper, we derive Hawking radiation in nonmarginally bound models from our exact solutions. We show that a nonvanishing energy function does not spoil the (approximate) Planck spectrum near the horizon. We can also reliably compute corrections to the Bogoliubov coefficient because our solutions are exact. The corrections are obtained by going beyond the near-horizon region and are shown to introduce additional greybody factors, which modify the blackbody spectrum of radiation from the black hole.

In a companion paper, we have introduced a model of scalar field dark energy, Cuscuton, which can be realized as the incompressible (or infinite speed of sound) limit of a $k$-essence fluid. In this paper, we study how Cuscuton modifies the constraint sector of Einstein gravity. In particular, we study Cuscuton cosmology and show that even though Cuscuton can have an arbitrary equation of state, or time dependence, and is thus inhomogeneous, its perturbations do not introduce any additional dynamical degree of freedom and only satisfy a constraint equation, amounting to an effective modification of gravity on large scales. Therefore, Cuscuton can be considered to be a minimal theory of evolving dark energy, or a minimal modification of a cosmological constant, as it has no internal dynamics. Moreover, this is the only modification of Einstein gravity to our knowledge, that does not introduce any additional degrees of freedom (and is not conformally equivalent to the Einstein gravity). We then study two simple Cuscuton models, with quadratic and exponential potentials. The quadratic model has the exact same expansion history as $\Lambda \mathrm{CDM}$, and yet contains an early dark energy component with constant energy fraction, which is constrained to ${\Omega }_Q\lesssim 2\%$, mainly from WMAP Cosmic Microwave Background and Sloan Digital Sky Survey Lyman-$\alpha$ forest observations. The exponential model has the same expansion history as the Dvali-Gabadadze-Poratti self-accelerating brane-world model, but generates a much smaller Integrated Sachs-Wolfe effect, and is thus consistent with the Cosmic Microwave Background observations. Finally, we show that the evolution is local on superhorizon scales, implying that there is no gross violation of causality, despite Cuscuton’s infinite speed of sound.