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The strong coupling alpha_s is a fundamental parameter of the Standard Model. In comparison to parameters like alpha_em and M_Z it is relatively poorly known. However the precision of alpha_s measurements has improved dramatically in recent…

High Energy Physics - Phenomenology · Physics 2007-05-23 W. J. Stirling

Orbital-free density functional theory (OF-DFT) constitutes a computationally highly effective tool for modeling electronic structures of systems ranging from room-temperature materials to warm dense matter. Its accuracy critically depends…

Quasar redshifts require the best possible precision and accuracy for a number of applications, such as setting the velocity scale for outflows as well as measuring small-scale quasar-quasar clustering. The most reliable redshift standard…

Astrophysics of Galaxies · Physics 2017-06-28 Michelle Mason , Michael Brotherton , Adam Myers

We measure shifts of the acoustic scale due to nonlinear growth and redshift distortions to a high precision using a very large volume of high-force-resolution simulations. We compare results from various sets of simulations that differ in…

Damped Ly$\alpha$ absorbers (DLAs) are the highest \HI\ column density (\NHI) absorption line systems detected in the spectra of background quasars. DLAs dominate the neutral gas content of the Universe ($\Omega_{\rm HI}$) and are used to…

Comparison of quasar absorption line spectra with laboratory spectra provides a precise probe for variability of the fine structure constant, alpha, over cosmological time-scales. We constrain variation in alpha in 21 Keck/HIRES Si IV…

Astrophysics · Physics 2009-08-18 M. T. Murphy , J. K. Webb , V. V. Flambaum , J. X. Prochaska , A. M. Wolfe

We directly measure the evolution of the intergalactic Lya effective optical depth, tau_eff, over the redshift range 2<z<4.2 from a sample of 86 high-resolution, high-signal-to-noise quasar spectra obtained with the ESI and HIRES…

Astrophysics · Physics 2009-11-13 C. -A. Faucher-Giguere , J. X. Prochaska , A. Lidz , L. Hernquist , M. Zaldarriaga

The designs of the first generation of cosmological 21-cm observatories are split between single dipole experiments which integrate over a large patch of sky in order to find the global (spectral) signature of reionization, and…

Cosmology and Nongalactic Astrophysics · Physics 2011-05-23 Jonathan M. Bittner , Abraham Loeb

An appealing approach for studying the reionization history of the Universe is to measure the redshift evolution of the Lyman-alpha fraction, the percentage of Lyman-break selected galaxies that emit appreciably in the Ly-alpha line. This…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-17 Jessie Taylor , Adam Lidz

Based on the disk galaxy formation theory within the framework of standard LCDM hierarchical picture, we selected modelled DLAs, according to their observational criterion, by Monte Carlo simulation with the random inclinations being…

Astrophysics · Physics 2015-06-24 J. L. Hou , C. G. Shu , S. Y. Shen , R. X. Chang , W. P. Chen , C. Q. Fu

The high resolution spectrograph ESPRESSO on the VLT allows measurements of fundamental constants at unprecedented precision and hence enables tests for spacetime variations predicted by some theories. In a series of recent papers, we…

Cosmology and Nongalactic Astrophysics · Physics 2023-03-08 Chung-Chi Lee , John K. Webb , Robert F. Carswell , Vladimir A. Dzuba , Victor V. Flambaum , Dinko Milaković

The Q weak experiment has made several interesting beam normal single spin asymmetry measurements. Preliminary result from a 3.2% measurement of the beam normal single spin asymmetry in elastic e+p scattering at E = 1.155 GeV and {\theta}…

Nuclear Experiment · Physics 2016-04-18 Buddhini P. Waidyawansa , the QWeak Collaboration

Comparison of the observed evolution of the Ly-alpha transmitted flux in the spectra of four highest redshift quasars discovered by SLOAN survey with the theoretical prediction for this evolution based on the state-of-the-art numerical…

Astrophysics · Physics 2007-05-23 Nickolay Y. Gnedin

We report results of a deep wide-field narrowband survey for redshift z~5.7 Ly alpha emitters carried out with SuprimeCam on Subaru 8.3-m telescope. Deep narrowband imaging of the SSA22 field through a 120 A bandpass filter centered at 8150…

Development of fundamental physics relies on the constancy of various fundamental quantities such as the fine structure constant. Detecting or constraining the possible time variations of these fundamental physical quantities is an…

Astrophysics · Physics 2009-11-10 H. Chand , R. Srianand , P. Petitjean , B. Aracil

Recent works have shown that small shifts in redshift -- gravitational redshift or systematic errors -- could potentially cause a significant bias in the estimation of cosmological parameters. I aim to verify whether a theoretical…

Cosmology and Nongalactic Astrophysics · Physics 2017-11-29 Jeong Hwa Kim

A more precise determination of the effective fine structure constant alpha_eff(E) is mandatory for confronting data from future precision experiments with precise SM predictions. At a future e+e- collider like the ILC, as at LEP before,…

High Energy Physics - Phenomenology · Physics 2008-11-26 F. Jegerlehner

We present a reanalysis of the HeII Lyman alpha absorption towards the quasars HS1700+6416 and HE2347-4342 using new high S/N, optical observations. An alternative analysis method is applied, which fits the high quality, optical HI data…

Astrophysics · Physics 2009-11-11 C. Fechner , D. Reimers

Density-functional-theory (DFT) calculations have been performed on the Li-Si and Li-Ge systems. Lithiated Si and Ge, including their metastable phases, play an important technological r\^ole as Li-ion battery (LIB) anodes. The calculations…

Materials Science · Physics 2015-06-18 Andrew J. Morris , C. P. Grey , C. J Pickard
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