Nature (2015)
Loophole-free Bell inequality violation using electron spins separated by 1.3 kilometres
Hansen et al.
More than 50 years ago. John Bell proved that no theory of nature that obeys locality and realism can reproduce all the predictions of quantum theory: in any local-realist theory, the correlations between outcomes of measurements on distant particles satisfy an inequality that can be violated if the particles are entangled. Numerous Bell inequality tests have been reported; however, all experiments reported so far required additional assumption to obtain a contradiction with local realism, resulting in 'loopholes'. Here, report a Bell experiment that is free of any such additional assumption and thus directly tests the principles underlying Bell's inequality. [...] Data imply statistically significant rejection of the local-realist null hypothesis.
1510.06442
Evidence for the kinematic Sunyaev-Zeldovich effect with ACTPol and velocity reconstruction from BOSS
Schaan, et al
Stack the CMB temperature at the halo, weighted by the corresponding reconstructed velocity. The resulting best fit kSZ model is preferred over the no-kSZ hypothesis at 3.3 sigma and 2.9 sigma for 2 independent velocity reconstruction methods, using 25537 galaxies over 660 square degrees.
1510.06665
Efficient construction of mock catalogs for Baryon Acoustic Oscillation surveys
Sunayama, Padmanabhan, Heitmann, Habib, Rangel
Precision measurements of the LSS of the universe require large numbers of high fidelity mock catalogs to accurately assess, and account for, the presence of systematic effects. Introduce and test a scheme for generating mock catalogs rapidly using suitable derated N-body sims. The aim is to reproduce the LSS and the gross properties of DM haloes with high accuracy, while sacrificing the details of the internal structure of the halos. By adjusting global and local time-steps in an N-body code, demonstrate that halo masses are recovered to better than 2% and the power spectrum (both in real and redshift space, for k=1h/Mpc) to better than 1%, while requiring a factor of 4 less CPU time. Also calibrate the redshift spacing of outputs required to generate simulated light cones. Find that outputs separated by every z=0.05 allow interpolation of particle positions and velocities to reproduce the real and redshift space power spectra to better than 1% (out to k-1h/Mpc). Apply the ideas to generate a suite of simulations spanning a range of cosmologies, motivated by BOSS but broadly applicable to future LSS surveys including eBOSS and DESI. As an initial demonstration of the utility of such simulations, calibrate the shift in the BAO peak position as a function of galaxy bias with higher precision than has been possible so far. This paper also serves to document the simulations, which is made publicly available.
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