Strong CP Violation in External Magnetic Fields

We study the response of the QCD vacuum to an external magnetic field, in the presence of strong CP violation. Using chiral perturbation theory and large N_c expansion, we show that the external field would polarize quantum fluctuations and induce an electric dipole moment of the vacuum, along the direction of the magnetic field. We estimate the magnitude of this effect in different physical scenarios. In particular, we find that the polarization induced by the magnetic field of a magnetar could accelerate electric charges up to energies of the order \theta 10^3 TeV. We also suggest a connection with the possible existence of "hot-spots" on the surface of neutron stars.Comment: 4 pages, 1 figure. Major revision. Phenomenological analysis extende

Remarkable symmetries in the Milky Way disk's magnetic field

Using a new, expanded compilation of extragalactic source Faraday rotation measures (RM) we investigate the broad underlying magnetic structure of the Galactic disk at latitudes $|b|$ $\lesssim 15^{\circ}$ over all longitudes $l$, where our total number of RM's in this low-latitude range of the Galactic sky is comparable to those in the combined Canadian Galactic Plane Survey(CGPS) at $|b| < 4^{\circ}$ and the Southern Galactic Plane (SGPS) $|b| < 1.5^{\circ}$ survey. We report newly revealed, remarkably coherent patterns of RM at $|b|$ $\lesssim 15^{\circ}$ from $l \sim 270^{\circ}$ to $\sim 90^\circ$ and RM($l$) features of unprecedented clarity that replicate in $l$ with opposite sign on opposite sides of the Galactic center. They confirm a highly patterned bisymmetric field structure toward the inner disc, an axisymmetic pattern toward the outer disc, and a very close coupling between the CGPS/SGPS RM's at $|b| \lesssim 3^{\circ}$ ("mid-plane") and our new RM's up to $|b| \sim 15^{\circ}$ ("near-plane"). Our analysis also shows the approximate $z$-height -- the vertical height of the coherent component of the disc field above the Galactic disc's mid-plane -- to be $\sim 1.5$kpc out to $\sim 6$ kpc from the Sun. This identifies the approximate height of the transition layer to the halo field structure. We find no RM sign change across the plane within $|b| \sim 15^{\circ}$ in any longitude range. The prevailing {\it disc} field pattern, and its striking degree of large scale ordering confirm that our side of the Milky Way has a very organized underlying magnetic structure, for which the inward spiral pitch angle is $5.5^{\circ}\, \pm 1^{\circ}$ at all $|b|$ up to $\sim 12^{\circ}$ in the inner semicircle of Galactic longitudes. It decreases to $\sim 0^{\circ}$ toward the anticentre.Comment: 7 pages, 5 figures, Version 3. Accepted 2011 for publication in Publications of the Astronomical Society of Australia(PASA

Ellipsoidal Universe Can Solve The CMB Quadrupole Problem

The recent three-year WMAP data have confirmed the anomaly concerning the low quadrupole amplitude compared to the best-fit \Lambda CDM prediction. We show that, allowing the large-scale spatial geometry of our universe to be plane-symmetric with eccentricity at decoupling or order 10^{-2}, the quadrupole amplitude can be drastically reduced without affecting higher multipoles of the angular power spectrum of the temperature anisotropy.Comment: 4 pages, 2 figures, minor changes, reference added, to appear in Phys. Rev. Let

Atomic layer deposition: Low temperature process well adapted to ULSI and TFT technologies

The high k dielectrics is an important materials to be integrate in future Ultra Large Scale Integration (ULSI) and future TFT technology. Indeed, to keep on the Moore\u27s Law curve, the reduction of silicon oxide (SiO2) thickness still required, but this reduction is hindered by tunneling current leakage limit. Consequently, it is important to replace SiO2 by another materials with high dielectric constant. The use of this material in manufacturing of gate dielectric in Thin-film transistor (TFT) and in Complementary Metal Oxide Semiconductor (CMOS) will increase gate capacitance with maintaining a low leakage current. Titanium dioxide is a good candidate due to its high dielectric constant in its rutile crystalline phase (180).This rutile structure is obtained at low temperature (250°C) by ALD deposition when TiO2 is deposited on ruthenium dioxide (RuO2) layer thanks to the small lattice mismatch between these two materials

On the Detection of Magnetic Helicity

Magnetic fields in various astrophysical settings may be helical and, in the cosmological context, may provide a measure of primordial CP violation during baryogenesis. Yet it is difficult, even in principle, to devise a scheme by which magnetic helicity may be detected, except in some very special systems. We propose that charged cosmic rays originating from known sources may be useful for this purpose. We show that the correlator of the arrival momenta of the cosmic rays is sensitive to the helicity of an intervening magnetic field. If the sources themselves are not known, the method may still be useful provided we have some knowledge of their spatial distribution.Comment: 5 pages, 1 figure, discussions and references added, submited to Phys. Rev.

Point-like gamma ray sources as signatures of distant accelerators of ultra high energy cosmic rays

We discuss the possibility of observing distant accelerators of ultra high energy cosmic rays in synchrotron gamma rays. Protons propagating away from their acceleration sites produce extremely energetic electrons during photo-pion interactions with cosmic microwave background photons. If the accelerator is embedded in a magnetized region, these electrons will emit high energy synchrotron radiation. The resulting synchrotron source is expected to be point-like and detectable in the GeV-TeV energy range if the magnetic field is at the nanoGauss level.Comment: 4 pages 2 figures. To be published in PR

Iterated maps for clarinet-like systems

The dynamical equations of clarinet-like systems are known to be reducible to a non-linear iterated map within reasonable approximations. This leads to time oscillations that are represented by square signals, analogous to the Raman regime for string instruments. In this article, we study in more detail the properties of the corresponding non-linear iterations, with emphasis on the geometrical constructions that can be used to classify the various solutions (for instance with or without reed beating) as well as on the periodicity windows that occur within the chaotic region. In particular, we find a regime where period tripling occurs and examine the conditions for intermittency. We also show that, while the direct observation of the iteration function does not reveal much on the oscillation regime of the instrument, the graph of the high order iterates directly gives visible information on the oscillation regime (characterization of the number of period doubligs, chaotic behaviour, etc.)

Normal mode simulation of prompt elastogravity signals induced by an earthquake rupture

As soon as an earthquake starts, the rupture and the propagation of seismic waves redistribute masses within the Earth. This mass redistribution generates in turn a long-range perturbation of the Earth gravitational field, which can be recorded before the arrival of the direct seismic waves. The recent first observations of such early signals motivate the use of the normal mode theory to model the elastogravity perturbations recorded by a ground-coupled seismometer or gravimeter. Complete modelling by normal mode summation is challenging due to the very large difference in amplitude between the prompt elastogravity signals and the direct P-wave signal. We overcome this problem by introducing a two-step simulation approach. The normal mode approach enables a fast computation of elastogravity signals in layered self-gravitating Earth models. The fast and accurate computation of gravity perturbations indicates instrument locations where signal detection may be achieved, and may prove useful in the implementation of a gravity-based earthquake early warning system