We reply to the preceding Comment by Fulling and Unruh criticizing our conclusion that principles of quantum field theory as of now do not give convincing arguments in favor of a universal thermal response of detectors uniformly accelerated in Minkowski space [Phys. Rev. D 65, 025004 (2002)]. We maintain our conclusion and present additional arguments to confirm it.

We dispute the conclusions of Narozhny et al. [Phys. Rev. D 65, 025004 (2002)] on numerous grounds.

Solutions of the coupled equations of general relativity and nonlinear electrodynamics with topology ${\mathrm{AdS}}_2\times {\mathrm{S}}^2$ are constructed and studied both analytically and numerically. It is shown that the near horizon limit of the extreme nonlinear black hole corresponds to the solution expressible in terms of the Lambert special functions. It is explicitly demonstrated that for the formulation of the nonlinear theory considered in this paper the resulting solutions do not belong to the Bertotti-Robinson class unless electrodynamics is Maxwellian. The question of the boundary conditions is briefly discussed.

We consider the BTZ black hole surrounded by the conformal scalar field. Within general relativity, the resonant quasinormal (QN) modes dominate in the response of a black hole to external perturbations. At the same time, the metric of an evaporating black hole is affected by the Hawking radiation. We estimate the shift in the quasinormal spectrum of the BTZ black hole stipulated by the back reaction of the Hawking radiation. For the case of the $\mathrm{}(2+1)\mathrm{}$-dimensional black hole the corrected (by $\sim ħ)$ metric is an exact solution [C. Martines and J. Zanelli, Phys. Rev. D 55, 3642 (1997)]. In addition, in this case quantum corrections come only from matter fields and not from graviton loops, that is, one can solve the problem of influence of the back reaction upon the QN ringing self-consistently. The dominant contribution to the corrections to the QNMs is simply a shift of ${\omega }^2$ proportional to $-(\Lambda {/M)}^{3/2}{(4L}^2+M)ħ.$ It is negligible for large black holes but essential for small ones, giving rise to considerable increasing of the quality factor. Thus, the small evaporating black hole is expected to be a much better oscillator than a large one.

Recently Davoudiasl et al. (hep-ph/0403019) have introduced a new type of interaction between the Ricci scalar R and the baryon current $J^{\mu },$ ${\partial }_{\mu }{\mathrm{RJ}}^{\mu }$ and proposed a mechanism for baryogenesis, the gravitational baryogenesis. Generally, however, ${\partial }_{\mu }R$ vanishes in the radiation-dominated era. In this paper we consider a generalized form of their interaction ${\partial }_{\mu }{f\left(R\right)J}^{\mu }$ and study again the possibility of gravitational baryo(lepto)genesis. Taking $f\left(R\right)\mathrm{}\sim \ln R,$ we will show that ${\partial }_{\mu }f\left(R\right)\mathrm{}\sim {\partial }_{\mu }R/R$ does not vanish and the required baryon number asymmetry can be naturally generated in the early universe.

We calculate axion radiation emitted in the collision of two straight global strings. The strings are supposed to be in the unexcited ground state, to be inclined with respect to each other, and to move in parallel planes. Radiation arises when the point of minimal separation between the strings moves faster than light. This effect exhibits a typical Cerenkov nature. Surprisingly, it allows an alternative interpretation as bremsstrahlung under a collision of point charges in $2+1$ electrodynamics. This can be demonstrated by suitable world-sheet reparametrizations and dimensional reduction. Rough cosmological estimates show that the contribution of the bremsstrahlung axions to the total axion density left after the QCD phase transition might exceed the contribution from the vacuum realignment.

We study Einstein-Yang-Mills equations in the presence of gravitating nontopological soliton field configurations, of q-ball type. We produce numerical solutions, stable with respect to gravitational collapse and to fission into free particles, and we study the effect of the field strength and the eigenfrequency to the soliton parameters. We also investigate the formation of such soliton stars when the spacetime is asymptotically anti–de Sitter.

We analyze open membranes immersed in a magnetic three-form field strength C. While cylindrical membranes in the absence of C behave like tensionless strings, when the C flux is present the strings polarize into thin membrane ribbons, locally orthogonal to the momentum density, thus providing the strings with an effective tension. The effective dynamics of the ribbons can be described by a simple deformation of the Schild action for null strings. Interactions become non-local due to the polarization, and lead to a deformation of the string field theory, whereby string vertices receive a phase factor proportional to the volume swept out by the ribbons. In a particular limit, this reduces to the non-commutative loop space found previously.

Based on the conformal energy theorem we prove the uniqueness theorem for static higher dimensional electrically and magnetically charged black holes being the solution of Einstein $\left(n-2\right)$-gauge forms equations of motion. Black holes spacetime contains an asymptotically flat spacelike hypersurface with compact interior and nondegenerate components of the event horizon.

The absorption cross section for scalar particle impact on a Schwarzschild black hole is found. The process is dominated by two physical phenomena. One of them is the well-known greybody factor that arises from the energy-dependent potential barrier outside the horizon that filters the incoming and outgoing waves. The other is related to the reflection of particles on the horizon (M.Yu. Kuchiev, gr-qc/0310008, [19,20]). This latter effect strongly diminishes the cross section for low energies, forcing it to vanish in the infrared limit. It is argued that this is a general property, the absorption cross section vanishes in the infrared limit for scattering of particles of arbitrary spin.

In the context of the Randall-Sundrum (RS) single-brane scenario, we discuss the bulk geometry and dynamics of a cosmological brane in terms of the local energy conservation law which exists for the bulk that allows slicing with a maximally symmetric three-space. This conservation law enables us to define a local mass in the bulk. We show that there is a unique generalization of the dark radiation on the brane, which is given by the local mass. We find there also exists a conserved current associated with the Weyl tensor, and the corresponding local charge, which we call the Weyl charge, is given by the sum of the local mass and a certain linear combination of the components of the bulk energy-momentum tensor. This expression of the Weyl charge relates the local mass to the projected Weyl tensor, $E_{\mu \nu },$ which plays a central role in the geometrical formalism of the RS braneworld. On the brane, in particular, this gives a decomposition of the projected Weyl tensor into the local mass and the bulk energy-momentum tensor. Then, as an application of these results, we consider a null dust model for the bulk energy-momentum tensor and discuss the black hole formation in the bulk. We investigate the causal structure by identifying the locus of the apparent horizon and clarify possible brane trajectories in the bulk. We find that the brane stays always outside the black hole as long as it is expanding. We also find an upper bound on the value of the Hubble parameter in terms of the matter energy density on the brane, irrespective of the energy flux emitted from the brane.

We study the vacuum C metric and its physical interpretation in terms of the exterior spacetime of a uniformly accelerating spherically-symmetric gravitational source. Wave phenomena on the linearized C metric background are investigated. It is shown that the scalar perturbations of the linearized C metric correspond to the gravitational Stark effect. This effect is studied in connection with the Pioneer anomaly.

It is well known that radiative corrections evaluated in nontrivial backgrounds lead to effective dispersion relations which are not Lorentz invariant. Since gravitational interactions increase with energy, gravity-induced radiative corrections could be relevant for the trans-Planckian problem. As a first step to explore this possibility, we compute the one-loop radiative corrections to the self-energy of a scalar particle propagating in a thermal bath of gravitons in Minkowski spacetime. We obtain terms which originate from the thermal bath and which indeed break the Lorentz invariance that possessed the propagator in the vacuum. Rather unexpectedly, however, the terms which break Lorentz invariance vanish in the high three-momentum limit. We also found that the imaginary part, which gives the rate of approach to thermal equilibrium, vanishes at one loop.

We investigate how the uncertainty of noncommutative spacetime affects inflation. For this purpose, the noncommutative parameter ${\mu }_0$ is taken to be a zeroth order slow-roll parameter. We calculate the noncommutative power spectrum up to second order using the slow-roll expansion. We find corrections arisen from a change of the pivot scale and the presence of a variable noncommutative parameter, when comparing with the commutative power spectrum. The power-law inflation is chosen to obtain explicit forms for the power spectrum, spectral index, and running spectral index. In cases of the power spectrum and spectral index, the noncommutative effect of higher-order corrections compensates for a loss of higher-order corrections in the commutative case. However, for the running spectral index, all higher-order corrections to the commutative case always provide negative spectral indexes, which could explain the recent WMAP data.

We study the entropy of a FRW universe filled with dark energy (cosmological constant, quintessence, or phantom). For the general or time-dependent equation of state $p=w\rho$ the entropy is expressed in terms of energy, Casimir energy, and w. The corresponding expression is reminiscent of the 2D conformal field theory (CFT) entropy only for conformal matter. At the same time, the cosmological Cardy-Verlinde formula relating three typical FRW universe entropies remains universal for any type of matter. The same conclusions hold in modified gravity, which represents the gravitational alternative for dark energy and which contains terms that increase at low curvature. It is interesting that black holes in modified gravity are more entropic than those in Einstein gravity. Finally, some hydrodynamical examples testing the new shear viscosity bound, which is expected to be the consequence of the holographic entropy bound, are presented for the early Universe in the plasma era and for the Kasner metric. It seems that the Kasner metric provides a counterexample to the new shear viscosity bound.

We develop a thorough description of neutrino oscillations in a magnetized protoneutron star, based on a resonance layer for neutrinos with different momentum directions. We apply our approach to the calculation of the asymmetry in the neutrino emission during the birth of a neutron star and the pulsar acceleration in the case of an active-sterile neutrino resonant conversion. The observed velocities can be obtained with the magnetic fields expected in the interior of a protoneutron star, for sterile neutrino masses of the order of KeV and small mixing angles.

We propose a new mechanism for magnetic field generation from inflation, by which strong magnetic fields can be generated on cosmological scales. These fields may be observable by cosmic microwave background radiation measurements, and may have a dynamical impact on structure formation. The mechanism is based on the observation that a light nearly minimally coupled charged scalar may be responsible for the creation of a negative photon mass squared (provided the scalar field coupling to the curvature scalar is small but negative), which in turn results in abundant photon production—and thus in growing magnetic fields—during inflation.

We consider bound states of a meson and a baryon (meson and antibaryon) in lattice QCD in a Euclidean formulation. For simplicity, considering the + parity sector we analyze an $\mathrm{SU}\mathrm{}\left(3\right)\mathrm{}$ theory with a single flavor in 2+1 dimensions and two-dimensional Dirac matrices. We work in the strong coupling regime, i.e., in a region of parameters such that the hopping parameter $\kappa$ is sufficiently small and $\kappa \gg g_0^{-2},$ where $g_0^{-2}$ is the pure gauge coupling. There is a meson (baryon) particle with asymptotic mass $-2\ln \kappa$ $\left(-3\ln \kappa \right)$ and an isolated dispersion curve. Here, in a ladder approximation, we show that there is no meson baryon (or meson-antibaryon) bound state solution to the Bethe-Salpeter equation up to the meson-baryon threshold $\left(\sim -5\ln \kappa \right).\mathrm{}$ The absence of such a bound state is an effect of a spatial range-one repulsive potential that is local in space at order ${\kappa }^3,$ i.e., the leading order in the hopping parameter $\kappa .$

We present a consistent color-flavor-spin-orbital wave function for a positive-parity ${\Theta }^{+}$ that naturally explains the observed narrowness of the state. The wave function is totally symmetric in its flavor-spin part and totally antisymmetric in its color-orbital part. If flavor-spin interactions dominate, this wave function renders the positive-parity ${\Theta }^{+}$ lighter than its negative-parity counterpart. We consider decays of the ${\Theta }^{+}$ and compute the overlap of this state with the kinematically allowed final states. Our results are numerically small. We note that dynamical correlations between quarks are not necessary to obtain narrow pentaquark widths.