Aspects of production and kinetic decoupling of non-thermal dark matter

We reconsider non-thermal production of WIMP dark matter in a systematic way and using a numerical code for accurate computations of dark matter relic densities. Candidates with large pair annihilation rates are favored, suggesting a connection with the anomalies in the lepton cosmic-ray flux detected by Pamela and Fermi. Focussing on supersymmetric models we will consider the impact of non-thermal production on the preferred mass scale for dark matter neutralinos. We have also developed a new formalism to solve the Boltzmann's equation for a system of coannihilating species without assuming kinetic equilibrium and applied it to the case of pure Winos.Comment: Proceedings for the conference TAUP 201

Heterotic strings on G_2 orbifolds

We study compactification of heterotic strings to three dimensions on orbifolds of G_2 holonomy. We consider the standard embedding and show that the gauge group is broken from E_8 x E_8 or SO(32) to F_4 x E_8 or SO(25) respectively. We also compute the spectrum of massless states and compare with the results obtained from reduction of the 10-dimensional fields. Non-standard embeddings are discussed briefly. For type II compactifications we verify that IIB and IIA have equal massless spectrum.Comment: LaTex, 21 page

System for Detection of Malicious Wireless Device Patterns

The research within presents the use of Hidden Markov Models (HMM) for the detection of wireless devices in highly noisy environments using their unintended electromagnetic emissions (UEE). All electromagnetic devices emit such radiation that is unique to the electronics, housing, and other device attributes. This pattern recognition system can provide continuous detection analysis and can provide ideal information regarding the distance to an unknown device. An experiment was performed where UEE of a device was detected by a spectrum analyzer. Experimental result shows that our model can accurately detect if there is a device nearby emitting UEE or not

Self-energies in itinerant magnets: A focus on Fe and Ni

We present a detailed study of local and non-local correlations in the electronic structure of elemental transition metals carried out by means of the Quasiparticle Self-consistent GW (QSGW ) and Dynamical Mean Field Theory (DMFT). Recent high resolution ARPES and Haas-van Alphen data of two typical transition metal systems (Fe and Ni) are used as case study. (i) We find that the properties of Fe are very well described by QSGW. Agreement with cyclotron and very clean ARPES measurements is excellent, provided that final-state scattering is taken into account. This establishes the exceptional reliability of QSGW also in metallic systems. (ii) Nonetheless QSGW alone is not able to provide an adequate description of the Ni ARPES data due to strong local spin fluctuations. We surmount this deficiency by combining nonlocal charge fluctuations in QSGW with local spin fluctuations in DMFT (QSGW + 'Magnetic DMFT'). (iii) Finally we show that the dynamics of the local fluctuations are actually not crucial. The addition of an external static field can lead to similarly good results if non-local correlations are included through QSGW

Scherk-Schwarz reduction of M-theory on G2-manifolds with fluxes

We analyse the 4-dimensional effective supergravity theories obtained from the Scherk--Schwarz reduction of M-theory on twisted 7-tori in the presence of 4-form fluxes. We implement the appropriate orbifold projection that preserves a G2-structure on the internal 7-manifold and truncates the effective field theory to an N=1, D=4 supergravity. We provide a detailed account of the effective supergravity with explicit expressions for the Kaehler potential and the superpotential in terms of the fluxes and of the geometrical data of the internal manifold. Subsequently, we explore the landscape of vacua of M-theory compactifications on twisted tori, where we emphasize the role of geometric fluxes and discuss the validity of the bottom-up approach. Finally, by reducing along isometries of the internal 7-manifold, we obtain superpotentials for the corresponding type IIA backgrounds.Comment: 43 pages, Latex; v3 typos corrected, one reference added, JHEP versio