Universal Behavior in Large-scale Aggregation of Independent Noisy Observations

Aggregation of noisy observations involves a difficult tradeoff between observation quality, which can be increased by increasing the number of observations, and aggregation quality which decreases if the number of observations is too large. We clarify this behavior for a protypical system in which arbitrarily large numbers of observations exceeding the system capacity can be aggregated using lossy data compression. We show the existence of a scaling relation between the collective error and the system capacity, and show that large scale lossy aggregation can outperform lossless aggregation above a critical level of observation noise. Further, we show that universal results for scaling and critical value of noise which are independent of system capacity can be obtained by considering asymptotic behavior when the system capacity increases toward infinity.Comment: 10 pages, 3 figure

How can we test seesaw experimentally?

The seesaw mechanism for the small neutrino mass has been a popular paradigm, yet it has been believed that there is no way to test it experimentally. We present a conceivable outcome from future experiments that would convince us of the seesaw mechanism. It would involve a variety of data from LHC, ILC, cosmology, underground, and low-energy flavor violation experiments to establish the case.Comment: 5 pages, 4 figure

Quark mass uncertainties revive KSVZ axion dark matter

The Kaplan-Manohar ambiguity in light quark masses allows for a larger uncertainty in the ratio of up to down quark masses than naive estimates from the chiral Lagrangian would indicate. We show that it allows for a relaxation of experimental bounds on the QCD axion, specifically KSVZ axions in the $2-3 \mu$eV mass range composing 100% of the galactic dark matter halo can evade the experimental limits placed by the ADMX collaboration.Comment: 9 pages, 5 figure

Cascade events at IceCube + DeepCore as a definitive constraint on the dark matter interpretation of the PAMELA and Fermi anomalies

Dark matter decaying or annihilating into μ^+μ^- or τ^+τ^- has been proposed as an explanation for the e^± anomalies reported by PAMELA and Fermi. Recent analyses show that IceCube, supplemented by DeepCore, will be able to significantly constrain the parameter space of decays to μ^+μ^-, and rule out decays to τ^+τ^- and annihilations to μ^+μ^- in less than five years of running. These analyses rely on measuring tracklike events in IceCube + DeepCore from down-going ν_μ. In this paper we show that by instead measuring cascade events, which are induced by all neutrino flavors, IceCube + DeepCore can rule out decays to μ^+μ^- in only three years of running, and rule out decays to τ^+τ^- and annihilation to μ^+μ^- in only one year of running. These constraints are highly robust to the choice of dark matter halo profile and independent of dark matter-nucleon crosssection

Stable splittings, spaces of representations and almost commuting elements in Lie groups

In this paper the space of almost commuting elements in a Lie group is studied through a homotopical point of view. In particular a stable splitting after one suspension is derived for these spaces and their quotients under conjugation. A complete description for the stable factors appearing in this splitting is provided for compact connected Lie groups of rank one.By using symmetric products, the colimits \Rep(\Z^n, SU), \Rep(\Z^n,U) and \Rep(\Z^n, Sp) are explicitly described as finite products of Eilenberg-MacLane spaces.Comment: 37 Pages. To appear in Math. Proc. Camb. Phil. So

Experimental Test of a New Equality: Measuring Heat Dissipation in an Optically Driven Colloidal System

Measurement of energy dissipation in small nonequilibrium systems is generally a difficult task. Recently, Harada and Sasa [Phys.Rev.Lett. 95, 130602(2005)] derived an equality relating the energy dissipation rate to experimentally accessible quantities in nonequilibrium steady states described by the Langevin equation. Here, we show the first experimental test of this new relation in an optically driven colloidal system. We find that this equality is validated to a fairly good extent, thus the irreversible work of a small system is estimated from readily obtainable quantities.Comment: 4 pages, 6 figure

High-Energy Neutrino Signatures of Dark Matter Decaying into Leptons

Decaying dark matter has previously been proposed as a possible explanation for the excess high energy cosmic ray electrons and positrons seen by PAMELA and the Fermi Gamma-Ray Space Telescope (FGST). To accommodate these signals however, the decays must be predominantly leptonic, to muons or taus, and therefore produce neutrinos, potentially detectable with the IceCube neutrino observatory. We find that, with five years of data, IceCube (supplemented by DeepCore) will be able to significantly constrain the relevant parameter space of decaying dark matter, and may even be capable of discovering dark matter decaying in the halo of the Milky Way.Comment: 4 pages, 1 figur

Discriminating spin through quantum interference

Many of the proposed solutions to the hierarchy and naturalness problems postulate new `partner' fields to the standard model particles. Determining the spins of these new particles will be critical in distinguishing among the various possible SM extensions, yet proposed methods rely on the underlying models. We propose a new model-independent method for spin measurements which takes advantage of quantum interference among helicity states. We demonstrate that this method will be able to discriminate scalar particles from higher spin states at the ILC, and discuss application to higher spins and possible uses at the LHC.Comment: 11 pages, 11 figure

111In Implantation in Iron and PAC Spectroscopy

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