8582068
Fractal structure of the harper map phase diagram from topological hierarchical classification
It is suggested a topological hierarchical classification of the infinite many Localized phases figuring in the phase diagram of the Harper equation for anisotropy parameter $\epsilon$ versus Energy $E$ with irrational magnetic flux $\omega$. It is also proposed a rule that explain the fractal structure of the phase diagram. Among many other applications, this system is equivalent to the Semi-classical problem of Bloch electrons in a uniform magnetic field, the Azbel-Hofstadter model, where the discrete magnetic translations operators constitute the quantum algebra $U_q(sl_2)$ with $q^2=e^{i2\pi\omega}$. The magnetic flux is taken to be the golden mean $\omega^*=(\sqrt{5}-1)/2$ and is obtained by successive rational approximants $\omega_m=F_{m-1}/F_m$ with $F_m$ given by the Fibonacci sequence $F_m$.[OUTP-00-08S, \texttt{cond-mat/0011396}]
119098673
Pseudo-Photon Radiative Corrections in Non-Regular Backgrounds
Extended $U_e(1)\times U_g(1)$ electromagnetism containing both a photon and a pseudo-photon is introduced at variational level and is justified by the violation of the Bianchi identities in conceptual systems, either in the presence of magnetic monopoles or non-regular external fields, not being accounted by the standard Maxwell action. It is shown that in the perturbative quantum field theory regimes there are observable consequences both for the magnetic momenta and second order vacuum polarization radiative corrections in the presence of non-regular strong electromagnetic fields (e.g. rotating magnetic fields).
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.
118869835
Heterotic, Open and Unoriented String Theories from Topological Membrane
In this work are consider several topics in the Topological Membrane (TM) approach to string theory. The string dynamics is generated from the bulk physics, namely from the 3D Topologically Massive Gauge Theory (TMGT) and Topologically Massive Gravity (TMG). Both (equivalent) path integral and canonical methods of quantizing TMGT are studied. It is shown that Narain constraints on toroidal compactification (integer, even, self-dual momentum lattice) have a natural interpretation in purely three dimensional terms. The Heterotic string and the block structure of c=1 RCFT are derived from the point of view of three dimensional field theory. Open and unoriented strings in TM(GT) theory are also studied through orbifolds of the bulk 3D space. This is achieved by gauging discrete symmetries of the theory. Open and unoriented strings can be obtained from all possible realizations of C, P and T symmetries. The important role of C symmetry to distinguish between Dirichlet and Neumann boundary conditions is discussed in detail. Future directions of research in this field are also suggested and discussed.
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.
18433177
Electro-Magnetic Space-Time Duality for 2+1 D Stationary Classical Solutions
We extend a space-time duality suggested by Kogan for 2+1-dimensional static classical solutions of Einstein Maxwell Chern-Simons theories to stationary rotating space-times. We also extend the original duality to other possible dualities of the same kind that constitute a close duality web. In 3+1-dimensions these dualities are only possible for systems which exhibit non-projected cylindrical symmetry and are not related to the usual electromagnetic duality of Maxwell equations. Generalization to $N$-form theories in higher dimensional space-times is briefly addressed.
119052706
Constraints on a primordial magnetic field
We derive an upper limit of B{sub 0}{lt}3.4{times}10{sup -9}({Omega}{sub 0}h{sup 2}{sub 50}){sup 1/2} G on the present strength of any primordial homogeneous magnetic field. The microwave background anisotropy created by cosmological magnetic fields is calculated in the most general flat and open anisotropic cosmologies containing expansion-rate and 3-curvature anisotropies. Our limit is derived from a statistical analysis of the 4-year Cosmic Background Explorer (COBE) data for anisotropy patterns characteristic of homogeneous anisotropy averaged over all possible sky orientations with respect to the COBE receiver. The limits we obtain on homogeneous magnetic fields are stronger than those imposed by nucleosynthesis. {copyright} {ital 1997} {ital The American Physical Society}
15403409
Evidence for non-Gaussianity in the COBE DMR Four Year Sky Maps
We introduce and study the distribution of an estimator for the normalized bispectrum of the Cosmic Microwave Background (CMB) anisotropy. We use it to construct a goodness of fit statistic to test the coadded 53 and 90 GHz COBE-DMR 4 year maps for non-Gaussianity. Our results indicate that Gaussianity is ruled out at the confidence level in excess of 98%. This value is a lower bound, given all the investigated systematics. The dominant non-Gaussian contribution is found near the multipole of order $\ell=16$. Our attempts to explain this effect as caused by the diffuse foreground emission from the Galaxy have failed. We conclude that unless there exists a microwave foreground emission which spatially correlates neither with the DIRBE nor Haslam maps, the cosmological CMB anisotropy is genuinely non-Gaussian.
9840308
Polarization-temperature correlation from a primordial magnetic field
We propose a new method for constraining a primordial homogeneous magnetic field with the cosmic microwave background. Such a field will induce an observable parity odd cross correlation between the polarization anisotropy and the temperature anisotropy by Faraday rotation. We analyze the necessary experimental features to match, and improve, current constraints of such a field by measuring this correlation.
15811055
The impact on cosmology of a primordial scaling field
A scalar field with an exponential potential has the particular property that it is attracted into a solution in which its energy scales as the dominant component (radiation or matter) of the Universe, contributing a fixed fraction of the total energy density. We briefly discuss the dynamics of such a scalar field and its impact on Big Bang nucleosynthesis, the growth of large scale structure and abundance of damped Lyman$-\alpha$ systems at high redshift. Given the simplicity of the model, its theoretical motivation, and its success in matching observations, we argue that it should be taken on par with other currently viable models of structure formation.
118589050
Avoiding Death by Vacuum
The two-Higgs doublet model (2HDM) can have two electroweak breaking, CP-conserving, minima. The possibility arises that the minimum which corresponds to the known elementary particle spectrum is metastable, a possibility we call the panic vacuum. We present analytical bounds on the parameters of the softly broken Peccei-Quinn 2HDM which are necessary and sufficient conditions to avoid this possibility. We also show that, for this particular model, the current LHC data already tell us that we are necessarily in the global minimum of the theory, regardless of any cosmological considerations about the lifetime of the false vacua.