Radio-loud Magnetars as Detectors for Axions and Axion-like Particles

We show that, by studying the arrival times of radio pulses from highly-magnetized transient beamed sources, it may be possible to detect light pseudo-scalar particles, such as axions and axion-like particles, whose existence could have considerable implications for the strong-CP problem of QCD as well as the dark matter problem in cosmology. Specifically, such light bosons may be detected with a much greater sensitivity, over a broad particle mass range, than is currently achievable by terrestrial experiments, and using indirect astrophysical considerations. The observable effect was discussed in Chelouche & Guendelman (2009), and is akin to the Stern-Gerlach experiment: the splitting of a photon beam naturally arises when finite coupling exists between the electro-magnetic field and the axion field. The splitting angle of the light beams linearly depends on the photon wavelength, the size of the magnetized region, and the magnetic field gradient in the transverse direction to the propagation direction of the photons. If radio emission in radio-loud magnetars is beamed and originates in regions with strong magnetic field gradients, then splitting of individual pulses may be detectable. We quantify the effect for a simplified model for magnetars, and search for radio beam splitting in the 2\,GHz radio light curves of the radio loud magnetar XTE\,J1810-197.Comment: 9 page

XMM-Newton Spectroscopy of the Starburst Dominated Ultra Luminous Infrared Galaxy NGC 6240

We present new XMM-Newton observation of the Ultra Luminous Infrared Galaxy (ULIRG) NGC 6240. We analyze the reflecting grating spectrometer (RGS) data, and data from the other instruments, and find a starburst dominated 0.5-3 keV spectrum with global properties resembling those observed in M82 but with a much higher luminosity. We show that the starburst region can be divided into an outer zone, beyond a radius of about 2.1 kpc, with a gas temperature of about 10^7 K and a central region with temperatures in the range (2-6) x 10^7 K. The gas in the outer region emits most of the observed Oviii Lyman-alpha line and the gas in the inner region the emission lines of higher ionization ions, including a strong Fexxv line. We also identify a small inner part, very close to the active nuclei, with typical Seyfert 2 properties including a large amount of photoionized gas producing a strong Fe K-alpha 6.4 keV line. The combined abundance, temperature and emission measure analysis indicates super solar Ne/O, Mg/O, Si/O, S/O and possibly also Fe/O. The analysis suggests densities in the range of (0.07-0.28) x epsilon^(-1/2) cm^(-3) and a total thermal gas mass of about 4 x 10^8 x epsilon^(1/2) solar masses, where epsilon is the volume filling factor. We used a simple model to argue that a massive starburst with an age of about 2 x 10^7 years can explain most of the observed properties of the source. NGC 6240 is perhaps the clearest case of an X-ray bright luminous AGN, in a merger, whose soft X-ray spectrum is dominated by a powerful starburst.Comment: 10 pages, 6 diagrams, accepted by ApJ, added a few minor change

Excessive noise as a test for many-body localization

Recent experimental reports suggested the existence of a finite-temperature insulator in the vicinity of the superconductor-insulator transition. The rapid decay of conductivity over a narrow temperature range was theoretically linked to both a finite-temperature transition to a many-body-localized state, and to a charge-Berezinskii-Kosterlitz-Thouless transition. Here we report of low-frequency noise measurements of such insulators to test for many-body localization. We observed a huge enhancement of the low-temperatures noise when exceeding a threshold voltage for nonlinear conductivity and discuss our results in light of the theoretical models

Adaptive Rich Media Presentations via Preference-Based Constrained Optimization

Personalization and adaptation of multi-media messages are well known and well studied problems. Ideally, each message should reflect its recipient\u27s interests, device capabilities, and network conditions. Such personalization is more difficult to carry out given a compound multi-media presentation containing multiple spatially and temporally related elements. This paper describes a novel formal, yet practical approach, and an implemented system prototype for authoring and adapting compound multi-media presentations. Our approach builds on recent advances in preference specification and preferences-based constrained optimization techniques

Cosmic Analogues of the Stern-Gerlach Experiment and the Detection of Light Bosons

We show that, by studying the arrival times of radio pulses from highly-magnetized pulsars, it may be possible to detect light spin-0 bosons (such as axions and axion-like particles) with a much greater sensitivity, over a broad particle mass range than is currently reachable by terrestrial experiments and indirect astrophysical bounds. In particular, we study the effect of splitting of photon-boson beams under intense magnetic field gradients in magnetars and show that radio pulses (at meter wavelengths) may be split and shift by a discernible phase down to a photon-boson coupling constant of g ~ 1e-14 [1/GeV]; i.e., about four orders of magnitude lower than current upper limits on g. The effect increases linearly with photon wavelength with split pulses having equal fluxes and similar polarizations. These properties make the identification of beam-splitting and beam deflection effects straightforward with currently available data. Better understanding of radio emission from magnetars is, however, required to confidently exclude regions in the parameter space when such effects are not observed.Comment: 4 pages, 3 figure

Brief for the National Association of Social Workers and the Ohio Chapter of the National Association of Social Workers as Amici Curie in Support of Petitioners, No. 13-933, United States Supreme Court (Mar. 6, 2014)

NASW\u27s first argument is simple. To protect children from abuse - a major congressional and state legislative goal - this Court should apply qualified immunity to protect social workers from personal liability where a reasonable decision has been made to remove a child without a warrant. NASW\u27s second argument is equally cogent. DeShaney was decided 25 years ago. Since then, this Court\u27s continued silence on the issue, Kovacic, 724 F.3d at 708 (Sutton, J., dissenting), has failed to provide guidance to those charged with the difficult task of protecting child welfare within the confines of the Fourth Amendment. Camreta v. Greene, 131 S. Ct. 2020, 2032 (2011). In light of the circuit split on this issue - compare Hatch v. Dep\u27t for Children, 274 F.3d 12 (1st Cir. 2001) with Kovacic, 724 F.3d (6th Cir. 2013) - guidance from this Court is more necessary today than ever

Brief for the National Association of Social Workers and the Ohio Chapter of the National Association of Social Workers as Amici Curie in Support of Petitioners, No. 13-933, United States Supreme Court (Mar. 6, 2014)

NASW\u27s first argument is simple. To protect children from abuse - a major congressional and state legislative goal - this Court should apply qualified immunity to protect social workers from personal liability where a reasonable decision has been made to remove a child without a warrant. NASW\u27s second argument is equally cogent. DeShaney was decided 25 years ago. Since then, this Court\u27s continued silence on the issue, Kovacic, 724 F.3d at 708 (Sutton, J., dissenting), has failed to provide guidance to those charged with the difficult task of protecting child welfare within the confines of the Fourth Amendment. Camreta v. Greene, 131 S. Ct. 2020, 2032 (2011). In light of the circuit split on this issue - compare Hatch v. Dep\u27t for Children, 274 F.3d 12 (1st Cir. 2001) with Kovacic, 724 F.3d (6th Cir. 2013) - guidance from this Court is more necessary today than ever