748074
A Pseudo-Photon in Non-Trivial Background Fields
We show that in the presence of external fields for which either Ḃ 6= 0 or ∇ × E 6= 0 it is not possible to derive the classical Maxwell equations from an action with only one gauge field. We suggest that one possible solution is to consider a second physical pseudo-vector gauge field C. The action for this theory is originally motivated by the inclusion of magnetic monopoles. These particles play no role in this work and our argument is only based in, that the violation of the Bianchi identities, cannot be accounted at the action level with only the standard gauge field. We give a particular example for a periodic rotating external magnetic field. Our construction holds that at classical level both the vector and pseudo-vector gauge fields A and C are regular. We compare pseudo-photon with paraphoton (graviphoton) theories concluding that, besides the mechanisms of gauge symmetry already studied by the authors, the Bianchi identities violation are a crucial difference between both theories. We also show that the effects in PVLAS experiment due to the inclusion of pseudo-photons cannot be distinguished from the usual classical induced electric and magnetic fields due to the standard Maxwell equations. Therefore, although this kind of optical experiments cannot test the existence of pseudo-photons, they do not exclude its existence. PACS: ?03.50.De, ?03.70.+k, ?11.15.-q
125353396
From compact U(1) Maxwell Chern-Simons to Azbel-Hofstadter: Testing magnetic monopoles and gravity to approximately 10**-17 meters on a nearby laboratory
6355453
Rotating Electric Classical Solutions of 2+1 D U(1) Einstein Maxwell Chern-Simons
We study electric stationary radial symmetric classical solutions of the U(1) Einstein Maxwell Chern-Simons theory coupled to a gravitational massless scalar field with a cosmological constant in 2+1 dimensions. Generic aspects of the theory are discussed at an introductory level. We study solutions for both negative sign (standard) and positive sign (ghost) of the gauge sector concluding that although the expressions for the solutions are the same, the constants as well as the physics change significantly. It is found a rotating electric point particle. For the standard sign and specific values of the parameters corresponding to solutions with positive mass the singularity is dressed (in the sense that itself constitutes an horizon). The space-time curvatures can be both positive or negative depending on the dominance of the scalar or topologically massive matter. The Chern-Simons term is responsible for interesting features, besides only allowing for rotating solutions, it imposes restrictive bounds on the cosmological constant $\Lambda$ such that it belongs to a positive interval and is switch on and off by the topological mass $m^2$. Furthermore the charge, angular momentum and mass of the particle solution are expressed uniquely as functions of the ratio between the cosmological constant and the topological mass squared $x=\Lambda/m^2$. The main drawback of our particle solution is that the mass is divergent. Our background is a rotating flat space without angular deficit. We briefly discuss parity and time-inversion violation by the Chern-Simons term which is explicit in the solutions obtained, their angular momentum only depends on the relative sign between the Chern-Simons term and the Maxwell term. Trivial solutions are briefly studied holding non-singular extended configurations.
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.
118480062
Landau-Ginzburg Chern-Simons model with Ue(1)xUg(1) Gauge Symmetry and Internal Pseudo-Photons
In this article it is studied, at variational level, a mathematical setup given by the Landau-Ginzburg Chern-Simons model for anyons in 2+1-dimensions within the framework of dimensional reduced Ue(1)xUg(1) extended electromagnetism with both vector gauge fields (photons) and pseudo-vector gauge fields (pseudo-photons) such that both magnetic and electric vortexes coexist in the planar system. This model exhibits explicit planar P and T discrete symmetries being the Hall conductivity consistently a tensor and the Dirac quantization on the electric and magnetic coupling constants is equivalent to the quantization of magnetic flux. It is also discussed a thickening to 4-dimensions of the model with explicit 4-dimensional P violation which allows either for electric and magnetic charge separation, either for the Meissner effect. Although mathematically consistent, the electromagnetic field content for this model does not coincide with the standard Hall effect being present an extra orthogonal electric and longitudinal magnetic fields.
118499251
Rotating Magnetic Solutions for 2+1D Einstein Maxwell Chern-Simons from Space-Time Duality
It is studied a space-time duality that maps known static rotating electric solutions into static magnetic solutions. As an example this dualities are applied to known electric solutions in 2+1-dimensional Minkowski space-times within the framework of Einstein Maxwell Chern-Simons theory coupled to a dilaton-like scalar field. The magnetic solutions obtained have metric determinant $\sqrt{-g}\sim r^p$ for the range of the parameter $p\in]-\infty,+\infty[/\{-1\}$ and are interpreted either as magnetic string-like configurations, configurations driven by an externally applied magnetic field or cosmological-like solutions with background magnetic fields.
85524781
Contributions from flavour changing effective operators to the physics of the top quark at LHC
We consider all relevant dimension six operators to perform a model independent analysis of flavour changing single top production at the LHC.
119264670
Ultralight axions: degeneracies with massive neutrinos and forecasts for future cosmological observations
A generic prediction of string theory is the existence of many axion fields. It has recently been argued that many of these fields should be light and, like the well known QCD axion, lead to observable cosmological consequences. In this paper we study in detail the effect of the so-called string axiverse on large scale structure, focusing on the morphology and evolution of density perturbations, anisotropies in the cosmic microwave background and weak gravitational lensing of distant galaxies. We quantify specific effects that will arise from the presence of the axionic fields and highlight possible degeneracies that may arise in the presence of massive neutrinos. We take particular care understanding the different physical effects and scales that come into play. We then forecast how the string axiverse may be constrained and show that with a combination of different observations, it should be possible to detect a fraction of ultralight axions to dark matter of a few percent.
119285987
Cosmology of Axions and Moduli: A Dynamical Systems Approach
xed point attractors, repellers and saddle points, which we analyse in detail. We also provide geometric interpretations of the phase space. The xed points can be used to bound the couplings in the model. A systematic scan of certain regions of parameter space reveals that the future evolution of the universe in this model can be rich, containing multiple epochs of accelerated expansion.
119273767
Dark matter, modified gravity, and the mass of the neutrino
It has been suggested that Einstein's theory of general relativity can be modified to accommodate mismatches between the gravitational field and luminous matter on a wide range of scales. Covariant theories of modified gravity generically predict the existence of extra degrees of freedom which may be interpreted as dark matter. We study a subclass of these theories where the overall energy density in these extra degrees of freedom is subdominant relative to the baryon density. We find that, although all theories we consider favor the presence of massive neutrinos, it is generally not possible to establish a lower limit on the neutrino mass. For a few very specific cases (such as a flat universe with a cosmological constant), we find a conservative lower bound on the neutrinos mass of m{sub {nu}}>0.31 eV.
36591368
Fast and precise map‐making for massively multi‐detector CMB experiments
Future cosmic microwave background (CMB) polarisation experiments aim to measure an unprecedentedly small signal - the primordial gravity wave component of the polarisation field B-mode. To achieve this, they will analyse huge dataset s, involving years worth of timeordered data (TOD) from massively multi-detector focal planes. This creates the need for fast and precise methods to complement the M-L approach in analysis pipelines. In this paper, we investigate fast map-making methods as applied to long duration, massively multi-detector, ground-based experiments, in the context of the search for B-modes. We focus on two alternative map-making approaches: destriping and TOD filtering , comparing their performance on simulated multi-detector polarisation data. We have written an optimised, parallel destriping code, the DEStriping CARTographer (DESCART), that is generalised for massive focal planes, including the potential effect of cross-correlate d TOD 1/f noise. We also determine the scaling of computing time for destriping as applied to a simulated full-season data-set for a realistic experiment. We find that destriping can out-perf orm filtering in estimating both the large-scale E and B-mode angular power spectra. In particular, filtering can produce significant spurious B-mode power via EB mixing. Whilst this can be removed, it contributes to the variance of B-mode bandpower estimates at scales near the primordial B-mode peak. For the experimental configuration we simulate, this has an effect o n the possible detection significance for primordial B-modes. Destriping is a viable alternative fast method to the full M-L approach that does not cause the problems associated with fil tering, and is flexible enough to