5,694 research outputs found

    Combining Full-Shape and BAO Analyses of Galaxy Power Spectra: A 1.6% CMB-independent constraint on H0

    Full text link
    We present cosmological constraints from a joint analysis of the pre- and post-reconstruction galaxy power spectrum multipoles from the final data release of the Baryon Oscillation Spectroscopic Survey (BOSS). Geometric constraints are obtained from the positions of BAO peaks in reconstructed spectra, analyzed in combination with the unreconstructed spectra in a full-shape (FS) likelihood using a joint covariance matrix, giving stronger parameter constraints than FS-only or BAO-only analyses. We introduce a new method for obtaining constraints from reconstructed spectra based on a correlated theoretical error, which is shown to be simple, robust, and applicable to any flavor of density-field reconstruction. Assuming Λ\LambdaCDM with massive neutrinos, we analyze data from two redshift bins zeff=0.38,0.61z_\mathrm{eff}=0.38,0.61 and obtain 1.6%1.6\% constraints on the Hubble constant H0H_0, using only a single prior on the current baryon density ωb\omega_b from Big Bang Nucleosynthesis (BBN) and no knowledge of the power spectrum slope nsn_s. This gives H0=68.6±1.1kms1Mpc1H_0 = 68.6\pm1.1\,\mathrm{km\,s}^{-1}\mathrm{Mpc}^{-1}, with the inclusion of BAO data sharpening the measurement by 40%40\%, representing one of the strongest current constraints on H0H_0 independent of cosmic microwave background data. Restricting to the best-fit slope nsn_s from Planck (but without additional priors on the spectral shape), we obtain a 1%1\% H0H_0 measurement of 67.8±0.7kms1Mpc167.8\pm 0.7\,\mathrm{km\,s}^{-1}\mathrm{Mpc}^{-1}. We find strong constraints on the cosmological parameters from a joint analysis of the FS, BAO, and Planck data. This sets new bounds on the sum of neutrino masses mν<0.14eV\sum m_\nu < 0.14\,\mathrm{eV} (at 95%95\% confidence) and the effective number of relativistic degrees of freedom Neff=2.900.16+0.15N_\mathrm{eff} = 2.90^{+0.15}_{-0.16}, though contours are not appreciably narrowed by the inclusion of BAO data.Comment: 42 pages, 12 figures, accepted by JCAP, likelihoods available at https://github.com/Michalychforever/lss_montepython (minor typo corrected

    The Generalisability of the Stages and Processes of Change ; The Concurrent Validity of the Stages and Processes of Change

    Get PDF
    The transtheorctical model of behaviour change is comprised of the stages of change and the processes of change. The stages explain when change occurs, and the processes outline how change occurs. This model has been influential in clinical practice in the areas of tobacco smoking, alcohol use, eating disorders, and exercise behaviour. This review focuses on the previous literature concerned with the transtheorctical model. Although the model is popular and used to tailor interventions, it has not yet been cross-culturally vaildated, or tested comprehensively in the field of illegal drug use. Further research is necessary to examine whether or not the model is appropriate for use with different clinical populations

    Long range order in non-equilibrium interacting quantum spin chains

    Full text link
    We conjecture that non-equilibrium boundary conditions generically trigger long range order in non-equilibrium steady states of locally interacting quantum chains. Our result is based on large scale density matrix renormalization group simulations of several models of quantum spin 1/2 chains which are driven far from equilibrium by coupling to a pair of unequal Lindblad reservoirs attached locally to the ends of the chain. In particular, we find a phase transition from exponentially decaying to long range spin-spin correlations in integrable Heisenberg XXZ chain by changing the anisotropy parameter. Long range order also typically emerges after breaking the integrability of the model.Comment: 4 pages, 4 figure

    Quantum Clock Synchronization: a Multi-Party Protocol

    Get PDF
    We present a multi-party quantum clock synchronization protocol that utilizes shared prior entanglement and broadcast of classical information to synchronize spatially separated clocks. Notably, it is necessary only for any one party to publish classical information. Consequently, the efficacy of the method is independent of the relative location of the parties. The suggested protocol is robust and does not require precise sequencing of procedural steps.Comment: 3 page

    Sagnac effect in a chain of mesoscopic quantum rings

    Full text link
    The ability to interferometrically detect inertial rotations via the Sagnac effect has been a strong stimulus for the development of atom interferometry because of the potential 10^{10} enhancement of the rotational phase shift in comparison to optical Sagnac gyroscopes. Here we analyze ballistic transport of matter waves in a one dimensional chain of N coherently coupled quantum rings in the presence of a rotation of angular frequency, \Omega. We show that the transmission probability, T, exhibits zero transmission stop gaps as a function of the rotation rate interspersed with regions of rapidly oscillating finite transmission. With increasing N, the transition from zero transmission to the oscillatory regime becomes an increasingly sharp function of \Omega with a slope \partialT/\partial \Omega N^2. The steepness of this slope dramatically enhances the response to rotations in comparison to conventional single ring interferometers such as the Mach-Zehnder and leads to a phase sensitivity well below the standard quantum limit
    corecore