119410476
Why Randall-Sundrum Scenarious are not Compatible with an Orbifolded Fifth Dimension
We show the (already known) fact that Randall-Sundrum scenarious although compatible with a ${\mathbb{Z}}_2$ orbifold symmetry cannot hold regularity of the fields at the orbifold planes in the absence of boundary actions and respective jumps of the fields. This makes the models mathematical inconsistence and invalidate the inclusion of such models in a higher dimensional theory such as string theory. For completeness we point out some directions already in the literature and in progress.
14262164
Mass for Plasma Photons from Gauge Symmetry Breaking
We derive the effective masses for photons in unmagnetized plasma waves using a quantum field theory with two vector fields (gauge fields). In order to properly define the quantum field degrees of freedom we re-derive the classical wave equations on light-front gauge. This is needed because the usual scalar potential of electromagnetism is, in quantum field theory, not a physical degree of freedom that renders negative energy eigenstates. We also consider a background local fluid metric that allows for a covariant treatment of the problem. The different masses for the longitudinal (plasmon) and transverse photons are in our framework due to the local fluid metric. We apply the mechanism of mass generation by gauge symmetry breaking recently proposed by the authors by giving a non-trivial vacuum-expectation-value to the second vector field (gauge field). The Debye length λ D is interpreted as an effective compactification length and we compute an explicit solution for the large gauge transformations that correspond to the specific mass eigenvalues derived here. Using an usual quantum field theory canonical quantization we obtain the usual results in the literature. Although none of these ingredients are new to physicist, as far as the authors are aware it is the first time that such constructions are applied to Plasma Physics. Also we give a physical interpretation (and realization) for the second vector field in terms of the plasma background in terms of known physical phenomena.
119391882
Effective Fractional Hall Effect with Pseudo-Photons
At variational level in the framework of dimensional reduced 'U_e(1)\times U_g(1)' electromagnetism it is considered an anyon Landau-Ginzburg Chern-Simons model for the fractional Hall effect. The collective gauge fields are due to pseudo-photons (...). We show that the model contains both magnetic vortexes due to the internal photons (interpreted as quasi-particles) and electric vortexes due to the internal pseudo-photons (interpreted as quasi-holes) that account for the anyon quantized magnetic flux and fractional electric charges, respectively. The effective magnetic flux is the only effective effect attributed to the standard internal photon which ensures compatibility between the pseudo nature of Laughlin's wave functions and macroscopical parity 'P' and time-inversion 'T' symmetries. In this way the model preserves these symmetries both at variational level and at the level of the electromagnetic equations. In particular holds the usual fractional Hall conductances with the Hall conductance '\hat{\sigma}_H' being a pseudo-scalar consistently with the electric Hall current equation. The negative energy contribution of quasi-holes to the Laughlin's wave function (...) is justified and the quantization of magnetic flux is directly equivalent to the Dirac's quantization condition applied to the coupling constants, or fundamental unit charges 'e' and 'g'. If our framework proves to be correct, quantization of magnetic flux may be the most direct evidence for Dirac's quantization condition. Our results also indicate that pseudo-photons electric vortex may give a theoretical justification for the electric potential between layers of bi-layer Hall systems.
16906939
Effect of Pions in Cosmic Rays
The effects of pions for vacuum polarization in background magnetic fields are considered. The effects of quark condensates is also briefly addresses. Although these effects are out of the measurement accuracy of laboratory experiments they may be relevant for gamma‐ray burst propagation. In particular, for emissions from the center of the galaxy, we show that the mixing between the neutral pion and photons results in a deviation of the gamma‐ray spectrum from the standard power‐law in the TeV range.
209833975
Does dark energy really exist
The article discusses the possibility that dark energy may not exist. The observations related to the expansion of the universe that caused scientists to initially infer its existence are noted. The alternative possibility that the Milky Way Galaxy lies in a giant cosmic void is also discussed, noting that scientists will make observations in the years following 2009 to determine which of the theories is correct. INSETS: COPERNICUS'S LEGACY;Three Ways of Expanding a Universe;A Special Place for Us;Surrender to the Void
122214245
A two-Higgs doublet model with remarkable CP properties
We analyze generalized CP symmetries of two-Higgs doublet models, extending them from the scalar to the fermion sector of the theory. We show that, other than the usual CP transformation, there is only one of those symmetries which does not imply massless charged fermions. That single model which accommodates a fermionic mass spectrum compatible with experimental data possesses a remarkable feature. Through a soft breaking of the symmetry it displays a new type of spontaneous CP violation, which does not occur in the scalar sector responsible for the symmetry breaking mechanism but, rather, in the fermion sector.
119498170
Non-zeta knots in the renormalization of the Wess-Zumino model?
Abstract We solve the Schwinger Dyson equations of the O ( N ) symmetric Wess-Zumino model at O (1/ N 3 ) at the non-trivial fixed point of the d -dimensional β -function and deduce a critical exponent for the wave function renormalization at this order. By developing the ϵ -expansion of the result, which agrees with known perturbation theory, we examine the distribution of transcendental coefficients and show that only the Riemann ζ series arises at this order in 1/ N . Unlike the analogous calculation at the same order in the bosonic O ( N ) φ 4 -theory non-zeta transcendentals, associated with for example the (3,4)-torus knot, cancel.
17460509
Simultaneous Estimation of Noise and Signal in Cosmic Microwave Background Experiments
To correctly analyse data sets from current microwave detection technology, one is forced to estimate the sky signal and experimental noise simultaneously. Given a time-ordered data set we propose a formalism and method for estimating the signal and associated errors without prior knowledge of the noise power spectrum. We derive the method using a Bayesian formalism and relate it to the standard methods; in particular we show how this leads to a change in the estimate of the noise covariance matrix of the sky signal. We study the convergence and accuracy of the method on two mock observational strategies and discuss its application to a currently-favoured calibration procedure.
119244228
Interacting spin-2 fields in the Stückelberg picture
We revisit and extend the `Effective field theory for massive gravitons' constructed by Arkani-Hamed, Georgi and Schwartz in the light of recent progress in constructing ghost-free theories with multiple interacting spin-2 fields. We show that there exist several dual ways of restoring gauge invariance in such multi-gravity theories, find a generalised Fierz-Pauli tuning condition relevant in this context and highlight subtleties in demixing tensor and scalar modes. The generic multi-gravity feature of scalar mixing and its consequences for higher order interactions are discussed. In particular we show how the decoupling limit is qualitatively changed in theories of interacting spin-2 fields. We relate this to dRGT (de Rham, Gabadadze, Tolley) massive gravity, Hassan-Rosen bigravity and the multi-gravity constructions by Hinterbichler and Rosen. As an additional application we show that EBI (Eddington-Born-Infeld) bigravity and higher order generalisations thereof possess ghost-like instabilities.