When a color superconductor of high density QCD is rotating, superfluid vortices are inevitably created along the rotation axis. In the color-flavor locked phase realized at the asymptotically large chemical potential, there appear non-Abelian vortices carrying both circulations of superfluid and color magnetic fluxes. A family of solutions has a degeneracy characterized by the Nambu-Goldstone modes $\mathbb{C}{P}^2$, associated with the color-flavor locked symmetry spontaneously broken in the vicinity of the vortex. In this paper, we study electromagnetic coupling of the non-Abelian vortices and find that the degeneracy is removed with the induced effective potential. We obtain one stable vortex solution and a family of metastable vortex solutions, both of which carry ordinary magnetic fluxes in addition to color magnetic fluxes. We discuss quantum mechanical decay of the metastable vortices by quantum tunneling and compare the effective potential with the other known potentials, the quantum mechanically induced potential and the potential induced by the strange quark mass.

Generalized uncertainty principles are able to serve as useful descriptions of some of the phenomenology of quantum gravity effects, providing an intuitive grasp on nontrivial space-time structures such as a fundamental discreteness of space, a universal band limit or an irreducible extendedness of elementary particles. In this article, uncertainty relations for single-particle quantum mechanics are derived by a moment expansion of states for quantum systems with a discrete coordinate and, correspondingly, a periodic momentum. Corrections to standard uncertainty relations are found, with some similarities but also key differences to what is often assumed in this context. The relations provided can be applied to discrete models of matter or space-time, including loop quantum cosmology.

We present tree-level scattering amplitudes in $\beta$-deformed super Yang-Mills theory in terms of new generating functions, derived by construction of a phase operator and application thereof to the $\mathcal{N}=4$ superamplitudes. The technique is explicitly illustrated for the maximally helicity violating (MHV) and next-to-MHV sectors. Along these lines we propose a phase representation of the $\mathcal{N}=4$ superconformal algebra realized on deformed amplitudes in the planar limit. Validity of the MHV vertex expansion is proven and a connection to nonplanar multiloop unitarity cuts is established. Our derivations are also compatible with the related $\gamma$-deformation.

Black hole accretion disks can form through the collapse of rotating massive stars. These disks produce large numbers of neutrinos and antineutrinos of electron flavor that can influence energetics and nucleosynthesis. Neutrinos are produced in sufficient numbers that, after they are emitted, they can undergo flavor transformation facilitated by the neutrino self interaction. We show that some of the neutrino flavor transformation phenomenology for accretion disks is similar to that of the supernova case, but also, we find the disk geometry lends itself to different transformation behaviors. These transformations strongly influence the nucleosynthetic outcome of disk winds.

We consider a generalization of the Jackiw-Pi model by introducing a nonstandard kinetic term. We present a Bogomolnyi framework for this theory and as a particular case we show that the Bogomolnyi equations of Chern-Simons Higgs theory can be obtained. Finally, the dimensionally reduced theory is analyzed and novel solitonic equations emerge.

This note supplements an earlier paper on conformal field theories. There it was shown how to construct tensor, spinor, and spinor-tensor primary fields in four dimensions from their counterparts in six dimensions, where conformal transformations act simply as $SO(4,2)$ Lorentz transformations. Here we show how to constrain fields in six dimensions so that the corresponding primary fields in four dimensions transform according to irreducible representations of the four-dimensional Lorentz group, even when the irreducibility conditions on these representations involve the four-component Levi-Civita tensor ${ϵ}_{\mu \nu \rho \sigma }$.

We construct new regular black hole solutions by matching the de Sitter solution and the Reissner-Nordström solution with a timelike thin shell. The thin shell is assumed to have mass but no pressure and obeys an equation of motion derived from Israel’s junction conditions. By investigating the equation of motion for the shell, we obtain stationary solutions of charged regular black holes and examine stability of the solutions. Stationary solutions are found in limited ranges of $0.87L\le m\le 1.99L$, and they are stable against small radial displacement of the shell with fixed values of $m$, $M$, and $Q$ if $M>0$, where $L$ is the de Sitter horizon radius, $m$ the black hole mass, $M$ the proper mass of the shell, and $Q$ the black hole charge. All the solutions obtained are highly charged in the sense of $Q/m>2\sqrt{3}\approx 0.866$. By taking the massless limit of the shell in the present regular black hole solutions, we obtain the charged regular black hole with a massless shell obtained by Lemos and Zanchin and investigate stability of the solutions. It is found that Lemos and Zanchin’s regular black hole solutions given by the massless limit of the present regular black hole solutions permit stable solutions, which are obtained by the limit of $M\to 0$.

The bimetric variational principle is a subtle reinterpretation of general relativity that assumes the spacetime connection to be generated by an independent metric. Unlike the so-called Palatini formalism that promotes the connection into a fundamental field, the new variational principle results in a physically distinct theory since the potential for the connection carries new degrees of freedom. Also, the connection-generating metric naturally allows an antisymmetric component. This sets torsion propagating. It is also shown here that while in the most straightforward generalization of the Einstein-Hilbert action the nonmetric degrees of freedom become ghosts, there exists very simple actions which give rise to viable theories at the linearized level when subjected to the bimetric variational principle. However, the nonlinear interactions might bring unpleasant features like the Boulware-Deser ghost. This remains to be explored since this new type of bimetric theories does not, in principle, lie in the class of usual bimetric theories where nonlinear interactions inevitably come in with new ghost-like degrees of freedom.

We explore the Reissner-Nordström naked singularities with a charge $Q$ larger than its mass $M$ from the perspective of particle acceleration. We first consider a collision between two test particles following the radial geodesics in the Reissner-Nordström naked singular geometry. An initially radially ingoing particle turns back due to the repulsive effect of gravity in the vicinity of a naked singularity. Such a particle then collides with another radially ingoing particle. We show that the center of mass energy of collision taking place at $r\approx M$ is unbound, in the limit where the charge transcends the mass by an arbitrarily small amount $0<1-M/Q\ll 1$. The acceleration process we describe avoids fine-tuning of the parameters of the particle geodesics for the unbound center of mass energy of collisions, and the proper time required for the process is also finite. We show that the coordinate time as observed by the distant observer required for the trans-Planckian collisions to occur around the naked singularity with one solar mass is merely of the order of million years, which is much smaller than the Hubble time. On the contrary, the time scale for collisions associated with an extremal black hole in an analogous situation is many orders of magnitude larger than the age of the Universe. We then study the collision of the neutral spherically symmetric shells made up of dust particles. In this case, it is possible to treat the situation by exactly taking into account the gravity due to the shells using Israel’s thin shell formalism, and thus this treatment allows us to go beyond the test particle approximation. The center of mass energy of collision of the shells is then calculated in a situation analogous to the test particle case and is shown to be bounded above. However, we find that the energy of a collision between two constituent particles of the shells at the center of mass frame can exceed the Planck energy.

In the standard approach to cosmological modeling in the framework of general relativity, the energy conditions play an important role in the understanding of several properties of the Universe, including singularity theorems, the current accelerating expansion phase, and the possible existence of the so-called phantom fields. Recently, the $f(T)$ gravity has been invoked as an alternative approach for explaining the observed acceleration expansion of the Universe. If gravity is described by a $f(T)$ theory instead of general relativity, there are a number of issues that ought to be reexamined in the framework of $f(T)$ theories. In this work, to proceed further with the current investigation of the limits and potentialities of the $f(T)$ gravity theories, we derive and discuss the bounds imposed by the energy conditions on a general $f(T)$ functional form. The null and strong energy conditions in the framework of $f(T)$ gravity are derived from first principles, namely the purely geometric Raychaudhuri equation along with the requirement that gravity is attractive. The weak and dominant energy conditions are then obtained in a direct approach via an effective energy-momentum tensor for $f(T)$ gravity. Although similar, the energy condition inequalities are different from those of general relativity, but in the limit $f(T)=T$, the standard forms for the energy conditions in general relativity are recovered. As a concrete application of the derived energy conditions to locally homogeneous and isotropic $f(T)$ cosmology, we use the recent estimated value of the Hubble parameter to set bounds from the weak energy condition on the parameters of two specific families of $f(T)$ gravity theories.

The reheating dynamics after the inflation induced by the $R^2$-corrected $f(R)$ model is considered. To avoid the complexity of solving the fourth order equations, we analyze the inflationary and reheating dynamics in the Einstein frame and its analytical solutions are derived. We also perform numerical calculations including the backreaction from the particle creation and compare the results with the analytical solutions. Based on the results, observational constraints on the model are discussed.

The $B$ (curl) mode of the correlation of galaxy ellipticities (shear) can be used to detect a stochastic gravitational wave background, such as that predicted by inflation. In this paper, we derive the tensor mode contributions to shear from both gravitational lensing and intrinsic alignments, using the gauge-invariant, full-sky results of Schmidt and Jeong {arXiv:1204.3625 [Phys. Rev. D (to be published)]}. We find that the intrinsic alignment contribution, calculated using the linear alignment model, is larger than the lensing contribution by an order of magnitude or more, if the alignment strength for tensor modes is of the same order as for scalar modes. This contribution also extends to higher multipoles. These results make the prospects for probing tensor modes using galaxy surveys less pessimistic than previously thought, though still very challenging.

Observed angular positions and redshifts of large-scale structure tracers such as galaxies are affected by gravitational waves through volume distortion and magnification effects. Thus, a gravitational wave background can in principle be probed through clustering statistics of large-scale structures. We calculate the observed angular clustering of galaxies in the presence of a gravitational wave background at linear order including all relativistic effects. For a scale-invariant spectrum of gravitational waves, the effects are most significant at the smallest multipoles ($2\le \ell \le 5$), but typically suppressed by six or more orders of magnitude with respect to scalar contributions for currently allowed amplitudes of the inflationary gravitational wave background. We also discuss the most relevant second-order terms, corresponding to the distortion of tracer correlation functions by gravitational waves. These provide a natural application of the approach recently developed in Schmidt and Jeong {arXiv:1204.3625 [Phys. Rev. D (to be published)]}.

We show the existence of a statistically significant, robust detection of a gamma-ray source in the Milky Way Galactic Center that is consistent with a spatially extended signal using about 4 years of Fermi-LAT data. The gamma-ray flux is consistent with annihilation of dark matter particles with a thermal annihilation cross section if the spatial distribution of dark matter particles is similar to the predictions of dark matter only simulations. We find statistically significant detections of an extended source with gamma-ray spectrum that is consistent with dark matter particle masses of approximately 10 GeV to 1 TeV annihilating to $b\overline{b}$ quarks and masses approximately 10–30 GeV annihilating to $\tau \overline{\tau }$ leptons. However, a part of the allowed region in this interpretation is in conflict with constraints from Fermi observations of the Milky Way satellites. The biggest improvement over the fit including just the point sources is obtained for a 30 GeV dark matter particle annihilating to $b\overline{b}$ quarks. The gamma-ray intensity and spectrum are also well fit with emission from a millisecond pulsar population following a density profile like that of low-mass x-ray binaries observed in M31. The greatest goodness of fit of the extended emission is with spectra consistent with known astrophysical sources like millisecond pulsars in globular clusters or cosmic-ray bremsstrahlung on molecular gas. Therefore, we conclude that the bulk of the emission is likely from an unresolved or spatially extended astrophysical source. However, the interesting possibility of all or part of the extended emission being from dark matter annihilation cannot be excluded at present.

We analytically and numerically investigate the evolutions of the scalar perturbations through the cycles with nonsingular bounces. It is found that the amplitude of the curvature perturbations on a large scale will be amplified cycle by cycle, and the isocurvature perturbations are also amplified, but the rate of amplification is slower than that of curvature perturbations, unless the coupling to the metric perturbation is not negligible.

We propose and constrain with the latest observational data, three model-independent parametrizations of the cosmic deceleration parameter $q(z)$. They are well behaved and stay finite at all redshifts. We construct them by fixing the value of $q$ at high redshift, $q(z\gg 1)=1/2$ (as demanded by cosmic structure formation), and at the far future $q(z=-1)=-1$, and smoothly interpolating $q(z)$ between them. The fixed point at $z=-1$ is not arbitrarily chosen; it readily follows from the second law of thermodynamics. This fairly reduces the ample latitude in parametrizing $q(z)$.

The fate of our universe is an unceasing topic of cosmology and the human being. The discovery of the current accelerated expansion of the universe significantly changed our view of the fate of the universe. Recently, some interesting scenarios concerning the fate of the universe attracted much attention in the community, namely the so-called “little rip” and “pseudo-rip”. It is worth noting that all the big rip, little rip and pseudo-rip arise from the assumption that the dark energy density $\rho (a)$ is monotonically increasing. In the present work, we are interested to investigate what will happen if this assumption is broken, and then propose a so-called “quasi-rip” scenario, which is driven by a type of quintom dark energy. In this work, we consider an explicit model of quasi-rip in detail. We show that quasi-rip has an unique feature different from big rip, little rip and pseudo-rip. Our universe has a chance to be rebuilt from the ashes after the terrible rip. This might be the last hope in the “hopeless” rip.

We study the deconfining phase transition at nonzero temperature in a $SU(N)$ gauge theory, using a matrix model which was analyzed previously at small $N$. We show that the model is soluble at infinite $N$, and exhibits a Gross-Witten-Wadia transition. In some ways, the deconfining phase transition is of first order: at a temperature $T_d$, the Polyakov loop jumps discontinuously from 0 to $\frac{1}{2}$, and there is a nonzero latent heat $\sim N^2$. In other ways, the transition is of second order: e.g., the specific heat diverges as $C\sim 1/(T-T_d{)}^{3/5}$ when $T\to T_d^{+}$. Other critical exponents satisfy the usual scaling relations of a second order phase transition. In the presence of a nonzero background field $h$ for the Polyakov loop, there is a phase transition at the temperature $T_h$ where the value of the $\mathrm{\text{loop}}=\frac{1}{2}$, with $T_h<T_d$. Since $\partial C/\partial T\sim 1/(T-T_h{)}^{1/2}$ as $T\to T_h^{+}$, this transition is of third order. These properties, closely analogous to those on a femtosphere at zero coupling, suggest that in infinite volume, the Gross-Witten-Wadia transition may be an infrared stable fixed point of a $SU(\infty )$ gauge theory.

Within the framework of the recently proposed ghost-free massive gravity, a cosmological constant-type self-accelerating solution has been obtained for Minkowski and de Sitter reference metrics. We ease the assumption on the reference metric and find the self-accelerating solution for the reference metric respecting only isotropy, thus considerably extending the range of known solutions.