We consider finite-size effects for the dyonic giant magnon of the type IIA string theory on ${\mathrm{AdS}}_4\times {\mathbb{C}\mathbb{P}}^3$ by applying the Lüscher $\mu$-term formula which is derived from a recently proposed $S$ matrix for the $\mathcal{N}=6$ super Chern-Simons theory. We compute explicitly the effect for the case of a symmetric configuration where the two external bound states, each of $A$ and $B$ particles, have the same momentum $p$ and spin $J_2$. We compare this with the classical string theory result which we computed by reducing it to the Neumann-Rosochatius system. The two results match perfectly.

We consider a triality between the Zermelo navigation problem, the geodesic flow on a Finslerian geometry of Randers type, and spacetimes in one dimension higher admitting a timelike conformal Killing vector field. From the latter viewpoint, the data of the Zermelo problem are encoded in a (conformally) Painlevé-Gullstrand form of the spacetime metric, whereas the data of the Randers problem are encoded in a stationary generalization of the usual optical metric. We discuss how the spacetime viewpoint gives a simple and physical perspective on various issues, including how Finsler geometries with constant flag curvature always map to conformally flat spacetimes and that the Finsler condition maps to either a causality condition or it breaks down at an ergo surface in the spacetime picture. The gauge equivalence in this network of relations is considered as well as the connection to analogue models and the viewpoint of magnetic flows. We provide a variety of examples.

We develop the complex angular momentum method in the context of the BTZ black hole physics. This is achieved by extending a formalism introduced a long time ago by Arnold Sommerfeld, which allows us to define and use the concept of the Regge pole in a framework where the notion of an $S$ matrix does not exist. The Regge poles of the BTZ black hole are exactly obtained, and from the associated Regge trajectories we determine its quasinormal mode complex frequencies. Furthermore, our approach permits us to physically interpret them: they appear as Breit-Wigner-type resonances generated by surface waves supported by the black hole boundary at infinity which acts as a photon sphere.

We consider the quasiblack hole limit of a stationary body when its boundary approaches its own gravitational radius, i.e., its quasihorizon. It is shown that there exists a perfect correspondence between the different mass contributions and the mass formula for quasiblack and black holes in spite of the difference in derivation and meaning of the formulas in both cases. For extremal quasiblack holes the finite surface stresses give zero contribution to the total mass. Analogous properties are derived for the angular momentum.

In this paper, we discuss the non-Gaussianity originated from the $\alpha$-vacuum on the cosmic microwave background anisotropy. For the $\alpha$-vacuum, there exists a correlation between points in the acausal two patches of de Sitter spactime. Such kind of correlation can lead to large local form non-Gaussianity in the $\alpha$-vacuum. For the single field slow-roll inflationary scenario, the space-time is in a quasi-de Sitter phase during the inflation. We will show that the $\alpha$-vacuum in this case will lead to non-Gaussianity with a distinguished feature, of a large local form and a very different shape.

We analyze the interaction between dark energy and dark matter from a thermodynamical perspective. By assuming they have different temperatures, we study the possibility of occurring a decay from dark matter into dark energy, characterized by a negative parameter $Q$. We find that, if at least one of the fluids has nonvanishing chemical potential, for instance ${\mu }_x<0$ and ${\mu }_{\mathrm{dm}}=0$ or ${\mu }_x=0$ and ${\mu }_{\mathrm{dm}}>0$, the decay is possible, where ${\mu }_x$ and ${\mu }_{\mathrm{dm}}$ are the chemical potentials of dark energy and dark matter, respectively. Using recent cosmological data, we find that, for a fairly simple interaction, the dark matter decay is favored with a probability of $\sim 93\%$ over the dark energy decay. This result comes from a likelihood analysis where only background evolution has been considered.

The excess of cosmic ray electron and positron fluxes measured by the PAMELA satellite and ATIC balloon experiments may be interpreted as the signals of the dark matter annihilation or decay into leptons. In this paper, we show that the dark matter annihilation/decay which reproduces the electron/positron excess may yield a significant amount of high-energy neutrinos from the Galactic center. In that case, future kilometer-square size experiments may confirm such a scenario, or even the Super-Kamiokande results already put constraints on some dark matter models.

Precision navigation of spacecraft requires accurate knowledge of small forces, including the recoil force due to anisotropies of thermal radiation emitted by spacecraft systems. We develop a formalism to derive the thermal recoil force from the basic principles of radiative heat exchange and energy-momentum conservation. The thermal power emitted by the spacecraft can be computed from engineering data obtained from flight telemetry, which yields a practical approach to incorporate the thermal recoil force into precision spacecraft navigation. Alternatively, orbit determination can be used to estimate the contribution of the thermal recoil force. We apply this approach to the Pioneer anomaly using a simulated Pioneer 10 Doppler data set.

The sensitivities of large arrays of low-background germanium detectors for solar-axion, or axionlike particle, searches are investigated in the context of several coupling scenarios. A search was made for the 14.4-keV axion branch from the M1 transition in the thermally excited ${}^{57}\mathrm{Fe}$ in the solar core in $80\mathrm{kg}\mathrm{d}$ of data from the International Germanium Experiment (IGEX) Dark Matter experiment. In one scenario, the direct couplings of axions to hadrons and to electrons were assumed to be in the range of the Peccei-Quinn scale $3\times {10}^5\le f_{\mathrm{PQ}}\le 7\times {10}^5\mathrm{GeV}$. This scenario is excluded by the IGEX data. In a second case, at the same Peccei-Quinn scale, coupling to photons and to electrons is suppressed. The IGEX data partially exclude this scenario depending on the degree of suppression. In the third case, the Peccei-Quinn scale for all couplings is assumed to be in the range $3\times {10}^6\le f_{\mathrm{PQ}}\le 7\times {10}^6\mathrm{GeV}$. Detection rates in Ge for all three scenarios are presented for several detector arrays.

We propose a model for $D^{+}\to {\pi }^{+}{\pi }^{-}{\pi }^{+}$ decays following experimental results which indicate that the two-pion interaction in the $S$ wave is dominated by the scalar resonances $f_0(600)/\sigma$ and $f_0(980)$. The weak decay amplitude for $D^{+}\to R{\pi }^{+}$, where $R$ is a resonance that subsequently decays into ${\pi }^{+}{\pi }^{-}$, is constructed in a factorization approach. In the $S$ wave, we implement the strong decay $R\to {\pi }^{+}{\pi }^{-}$ by means of a scalar form factor. This provides a unitary description of the pion-pion interaction in the entire kinematically allowed mass range $m_{\pi \pi }^2$ from threshold to about $3{\mathrm{GeV}}^2$. In order to reproduce the experimental Dalitz plot for $D^{+}\to {\pi }^{+}{\pi }^{-}{\pi }^{+}$, we include contributions beyond the $S$ wave. For the $P$ wave, dominated by the $\rho (770{)}^0$, we use a Breit-Wigner description. Higher waves are accounted for by using the usual isobar prescription for the $f_2(1270)$ and $\rho (1450{)}^0$. The major achievement is a good reproduction of the experimental $m_{\pi \pi }^2$ distribution, and of the partial as well as the total $D^{+}\to {\pi }^{+}{\pi }^{-}{\pi }^{+}$ branching ratios. Our values are generally smaller than the experimental ones. We discuss this shortcoming and, as a by-product, we predict a value for the poorly known $D\to \sigma$ transition form factor at $q^2=m_{\pi }^2$.

We study the deeply virtual Compton scattering amplitude within the color dipole approach. The light-cone wave function of a real photon is evaluated in the instanton vacuum model. Our parameter-free calculations are able to describe H1 data, both the absolute values and the $t$ dependences, at medium-high values of $Q^2$. The $Q^2$ dependence is found to be sensitive to the choice of the phenomenological cross section fitted to deep-inelastic scattering data.

A Bogomol’nyi-Prasad-Sommerfield (BPS) 3-cycle in a Sasaki-Einstein 5-manifold in general does not minimize volume in its homology class, as we illustrate with several examples of nonminimal volume BPS cycles on the 5-manifolds $Y^{p,q}$. Instead they minimize the energy of a wrapping D-brane, extremizing a generalized calibration. We present this generalized calibration and demonstrate that it reproduces both the Born-Infeld and the Wess-Zumino parts of the D3-brane energy.

It was shown by Buchbinder, Buchel, and Vazquez [J. High Energy Phys. 12 (2008) 090] that, in the presence of the magnetic field, the sound waves in ($2+1$)-dimensional plasma disappear and are replaced by a diffusive mode. Similarly, the shear and charge diffusion fluctuations form a subdiffusive mode. However, since the limit of a small magnetic field does not commute with the hydrodynamic limit, it is not obvious whether or not these modes are stable under higher order corrections. Using AdS/CFT correspondence we show that, in the case of the $M2$-brane plasma, these modes do exist as we find the corresponding supergravity solutions. This allowed us to compute the conductivity and the shear viscosity to all orders in a magnetic field. We find that the viscosity to entropy ratio saturates the Kovtun-Son-Starinets bound. This extends the universality property of the shear viscosity to the case of the strongly coupled plasma in an external magnetic field.

We continue the studies of localization of the U(1) gauge fields on domain walls. Depending on dynamics of the bulk theory the gauge field localized on the domain wall can be either in the Coulomb phase or squeezed into flux tubes implying (Abelian) confinement of probe charges on the wall along the wall surface. First, we consider a simple toy model with one flavor in the bulk at weak coupling (a minimal model) realizing the latter scenario. We then suggest a model presenting an extension of the Seiberg-Witten theory which is at strong coupling, but all theoretical constructions are under full control if we base our analysis on a dual effective action. Finally, we compare our findings with the wall in a “nonminimal” theory with two distinct quark flavors that had been studied previously. In this case the U(1) gauge field trapped on the wall is exactly massless because it is the Goldstone boson of a U(1) symmetry in the bulk spontaneously broken on the wall. The theory on the wall is in the Coulomb phase. We explain why the mechanism of confinement discussed in the first part of the paper does not work in this case, and strings are not formed on the walls.

Configurations of vortex strings stretched between or ending on domain walls were previously found to be $1/4$ Bogomol’nyi-Prasad-Sommerfield (BPS) states in $\mathcal{N}=2$ supersymmetric gauge theories in $3+1$ dimensions. Among zero modes of string positions, the center of mass of strings in each region between two adjacent domain walls is shown to be non-normalizable whereas the rests are normalizable. We study dynamics of vortex strings stretched between separated domain walls by using two methods, the moduli space (geodesic) approximation of full $1/4$ BPS states and the charged particle approximation for string end points in the wall effective action. In the first method we explicitly obtain the effective Lagrangian in the strong coupling limit, which is written in terms of hypergeometric functions, and find the 90° scattering for head-on collision. In the second method the domain wall effective action is assumed to be $U(1{)}^N$ gauge theory, and we find a good agreement between two methods for well-separated strings.

The trace anomaly of quantum fields in electromagnetic or gravitational backgrounds implies the existence of massless scalar poles in physical amplitudes involving the stress-energy tensor. Considering first the axial anomaly and using QED as an example, we compute the full one-loop triangle amplitude of the fermionic stress tensor with two current vertices, $⟨T^{\mu \nu }{J}^{\alpha }{J}^{\beta }⟩$, and exhibit the scalar pole in this amplitude associated with the trace anomaly, in the limit of zero electron mass $m\to 0$. To emphasize the infrared aspect of the anomaly, we use a dispersive approach and show that this amplitude and the existence of the massless scalar pole is determined completely by its ultraviolet finite terms, together with the requirements of Poincaré invariance of the vacuum, Bose symmetry under interchange of $J^{\alpha }$ and $J^{\beta }$, and vector current and stress-tensor conservation. We derive a sum rule for the appropriate positive spectral function corresponding to the discontinuity of the triangle amplitude, showing that it becomes proportional to $\delta (k^2)$ and therefore contains a massless scalar intermediate state in the conformal limit of zero electron mass. The effective action corresponding to the trace of the triangle amplitude can be expressed in local form by the introduction of two scalar auxiliary fields which satisfy massless wave equations. These massless scalar degrees of freedom couple to classical sources, contribute to gravitational scattering processes, and can have long range gravitational effects.

In recent years, a growing momentum has been gained by the emergent gravity framework. Within the latter, the very concepts of geometry and gravitational interaction are not seen as elementary aspects of nature but rather as collective phenomena associated to the dynamics of more fundamental objects. In this paper we want to further explore this possibility by proposing a model of emergent Lorentzian signature and scalar gravity. Assuming that the dynamics of the fundamental objects can give rise in first place to a Riemannian manifold and a set of scalar fields we show how time (in the sense of hyperbolic equations) can emerge as a property of perturbations dynamics around some specific class of solutions of the field equations. Moreover, we show that these perturbations can give rise to a spin-0 gravity via a suitable redefinition of the fields that identifies the relevant degrees of freedom. In particular, we find that our model gives rise to Nordström gravity. Since this theory is invariant under general coordinate transformations, this also shows how diffeomorphism invariance (albeit of a weaker form than the one of general relativity) can emerge from much simpler systems.

The primordial curvature fluctuation spectrum is reconstructed by the maximum likelihood reconstruction method using the five-year Wilkinson Microwave Anisotropy Probe data of the cosmic microwave background temperature anisotropy. We apply the covariance matrix analysis and decompose the reconstructed spectrum into statistically independent band powers. The prominent peak off a simple power-law spectrum found in our previous analysis turn out to be a $3.3\sigma$ deviation. From the statistics of primordial spectra reconstructed from mock observations, the probability that a primordial spectrum including such excess is realized in a power-law model is estimated to be about 2%.

We discuss the possibility to suppress downward atmospheric neutrinos in a high energy neutrino telescope. This can be achieved by vetoing the muon which is produced by the same parent meson decaying in the atmosphere. In principle, atmospheric neutrinos with energies $E_{\nu }>10\mathrm{TeV}$ and a zenith angle up to 60° can be vetoed with an efficiency of $>99\%$. Practical realization will depend on the depth of the neutrino telescope, on the muon veto efficiency, and on the ability to identify downward-moving neutrinos with a good energy estimation.

In a recent paper [A. G. Aksenov, R. Ruffini, and G. V. Vereshchagin, Phys. Rev. Lett. 99, 125003 (2007).] we considered the approach of nonequilibrium pair plasma towards a thermal equilibrium state adopting a kinetic treatment and solving numerically the relativistic Boltzmann equations. It was shown that plasma in the energy range 0.1–10 MeV reaches kinetic equilibrium first, on a time scale $t_{\mathrm{k}}\lesssim {10}^{-14}\sec$, with detailed balance between binary interactions such as Compton, Bhabha, and Møller scattering, and pair production and annihilation. Later the electron-positron-photon plasma approaches thermal equilibrium on a time scale $t_{\mathrm{th}}\lesssim {10}^{-12}\sec$, with detailed balance for all direct and inverse reactions. In the present paper we systematically present details of the computational scheme used there, as well as generalize our treatment, considering proton loading of the pair plasma. When proton loading is large, protons thermalize first by proton-proton scattering, and then, with the electron-positron-photon plasma, by proton-electron scattering. In the opposite case of small proton loading, proton-electron scattering dominates over proton-proton scattering. Thus in all cases the plasma, even with a proton admixture, reaches a thermal equilibrium configuration on a time scale $t_{\mathrm{th}}\lesssim {10}^{-11}\sec$. We show that it is crucial to account for not only binary but also triple direct and inverse interactions between electrons, positrons, photons, and protons. Several explicit examples are given, and the corresponding time scales for reaching kinetic and thermal equilibria are determined.