Minimal Neutrino Beta Beam for Large theta_13

We discuss the minimum requirements for a neutrino beta beam if theta_13 is discovered by an upcoming reactor experiment, such as Double Chooz or Daya Bay. We require that both neutrino mass hierarchy and leptonic CP violation can be measured to competitive precisions with a single-baseline experiment in the entire remaining theta_13 range. We find that for very high isotope production rates, such as they might be possible using a production ring, a (B,Li) beta beam with a gamma as low as 60 could already be sufficient to perform all of these measurements. If only the often used nominal source luminosities can be achieved, for example, a (Ne,He) beta beam from Fermilab to a possibly existing water Cherenkov detector at Homestake with gamma \sim 190-350 (depending on the Double Chooz best-fit) could outperform practically any other beam technology including wide-band beam and neutrino factory.Comment: 11 pages, 2 figures, 1 tabl

Physics Potential of a 2540 Km Baseline Superbeam Experiment

We study the physics potential of a neutrino superbeam experiment with a 2540 km baseline. We assume a neutrino beam similar to the NuMI beam in medium energy configuration. We consider a 100 kton totally active scintillator detector at a 7 mr off-axis location. We find that such a configuration has outstanding hierarchy discriminating capability. In conjunction with the data from the present reactor neutrino experiments, it can determine the neutrino mass hierarchy at 3 sigma level in less than 5 years, if sin^2(2*theta13) > 0.01, running in the neutrino mode alone. As a stand alone experiment, with a 5 year neutrino run and a 5 year anti-neutrino run, it can determine non-zero theta13 at 3 sigma level if sin^2(2*theta13) > 7*10^{-3} and hierarchy at 3 sigma level if sin^2(2*theta13) > 8*10^{-3}. This data can also distinguish deltaCP = pi/2 from the CP conserving values of 0 and pi, for sin^2(2*theta13) > 0.02.Comment: 16 pages, 7 figures and 1 table: Published versio

Discovery of the secondary eclipse of HAT-P-11 b

We report the detection of the secondary eclipse of HAT-P-11 b, a Neptune-sized planet orbiting an active K4 dwarf. Using all available short-cadence data of the Kepler mission, we derive refined planetary ephemeris increasing their precision by more than an order of magnitude. Our simultaneous primary and secondary transit modeling results in improved transit and orbital parameters. In particular, the precise timing of the secondary eclipse allows to pin down the orbital eccentricity to $0.26459_{-0.00048}^{+0.00069}$. The secondary eclipse depth of $6.09_{-1.11}^{+1.12}$ ppm corresponds to a $5.5\sigma$ detection and results in a geometric albedo of $0.39\pm0.07$ for HAT-P-11 b, close to Neptune's value, which may indicate further resemblances between these two bodies. Due to the substantial orbital eccentricity, the planetary equilibrium temperature is expected to change significantly with orbital position and ought to vary between $630^\circ$ K and $950^\circ$ K, depending on the details of heat redistribution in the atmosphere of HAT-P-11 b.Comment: Accepted by A&A, 27/10/201

Solar mass-varying neutrino oscillations

We propose that the solar neutrino deficit may be due to oscillations of mass-varying neutrinos (MaVaNs). This scenario elucidates solar neutrino data beautifully while remaining comfortably compatible with atmospheric neutrino and K2K data and with reactor antineutrino data at short and long baselines (from CHOOZ and KamLAND). We find that the survival probability of solar MaVaNs is independent of how the suppression of neutrino mass caused by the acceleron-matter couplings varies with density. Measurements of MeV and lower energy solar neutrinos will provide a rigorous test of the idea.Comment: 4 pages, 3 figures. Version to appear in PR

A planetary eclipse map of CoRoT-2a. Comprehensive lightcurve modeling combining rotational-modulation and transits

We analyze the surface structure of the planet host star CoRoT-2a using a consistent model for both the `global' (i.e., rotationally modulated) lightcurve and the transit lightcurves, using data provided by the CoRoT mission. Selecting a time interval covering two stellar rotations and six transits of the planetary companion CoRoT-2b, we adopt a `strip' model of the surface to reproduce the photometric modulation inside and outside the transits simultaneously. Our reconstructions show that it is possible to achieve appropriate fits for the entire sub-interval using a low-resolution surface model with 36 strips. The surface reconstructions indicate that the brightness on the eclipsed section of the stellar surface is (6 +/- 1) % lower than the average brightness of the remaining surface. This result suggests a concentration of stellar activity in a band around the stellar equator similar to the behavior observed on the Sun.Comment: accepted by A&A on 12/09/200

Interplay between nanometer-scale strain variations and externally applied strain in graphene

We present a molecular modeling study analyzing nanometer-scale strain variations in graphene as a function of externally applied tensile strain. We consider two different mechanisms that could underlie nanometer-scale strain variations: static perturbations from lattice imperfections of an underlying substrate and thermal fluctuations. For both cases we observe a decrease in the out-of-plane atomic displacements with increasing strain, which is accompanied by an increase in the in-plane displacements. Reflecting the non-linear elastic properties of graphene, both trends together yield a non-monotonic variation of the total displacements with increasing tensile strain. This variation allows to test the role of nanometer-scale strain variations in limiting the carrier mobility of high-quality graphene samples

Echoes of the electroweak phase transition: discovering a second Higgs doublet through A0 → ZH0

The existence of a second Higgs doublet in nature could lead to a cosmological first-order electroweak phase transition and explain the origin of the matter-antimatter asymmetry in the Universe. We obtain the spectrum and properties of the new scalars H0, A0, and H� that signal such a phase transition and show that the observation of the decay A0 → ZH0 at LHC would be a “smoking gun” signature of these scenarios. We analyze the LHC search prospects for this decay in the llbb¯ and llWþW− final states, arguing that current data may be sensitive to this signature in the former channel as well as there being great potential for a discovery in either channel at the very early stages of the 14 TeV run

Purification of genuine multipartite entanglement

In tasks, where multipartite entanglement plays a central role, state purification is, due to inevitable noise, a crucial part of the procedure. We consider a scenario exploiting the multipartite entanglement in a straightforward multipartite purification algorithm and compare it to bipartite purification procedures combined with state teleportation. While complete purification requires an infinite amount of input states in both cases, we show that for an imperfect output fidelity the multipartite procedure exhibits a major advantage in terms of input states used.Comment: 5 pages, 2 figure