A generalized phase space approach for solving quantum spin dynamics

Numerical techniques to efficiently model out-of-equilibrium dynamics in interacting quantum many-body systems are key for advancing our capability to harness and understand complex quantum matter. Here we propose a new numerical approach which we refer to as GDTWA. It is based on a discrete semi-classical phase-space sampling and allows to investigate quantum dynamics in lattice spin systems with arbitrary $S\geq 1/2$. We show that the GDTWA can accurately simulate dynamics of large ensembles in arbitrary dimensions. We apply it for $S>1/2$ spin-models with dipolar long-range interactions, a scenario arising in recent experiments with magnetic atoms. We show that the method can capture beyond mean-field effects, not only at short times, but it also correctly reproduces long time quantum-thermalization dynamics. We benchmark the method with exact diagonalization in small systems, with perturbation theory for short times, and with analytical predictions made for closed system which feature quantum-thermalization at long times. By computing the Renyi entropy, currently an experimentally accessible quantifier of entanglement, we reveal that large $S$ systems can feature larger entanglement than corresponding $S=1/2$ systems. Our analyses demonstrate that the GDTWA can be a powerful tool for modeling complex spin dynamics in regimes where other state-of-the art numerical methods fail

Light scattering from dense cold atomic media

We theoretically study the propagation of light through a cold atomic medium, where the effects of motion, laser intensity, atomic density, and polarization can all modify the properties of the scattered light. We present two different microscopic models: the "coherent dipole model" and the "random walk model", both suitable for modeling recent experimental work done in large atomic arrays in the low light intensity regime. We use them to compute relevant observables such as the linewidth, peak intensity and line center of the emitted light. We further develop generalized models that explicitly take into account atomic motion. Those are relevant for hotter atoms and beyond the low intensity regime. We show that atomic motion can lead to drastic dephasing and to a reduction of collective effects, together with a distortion of the lineshape. Our results are applicable to model a full gamut of quantum systems that rely on atom-light interactions including atomic clocks, quantum simulators and nanophotonic systems

Evaporative cooling of reactive polar molecules confined in a two-dimensional geometry

Recent experimental developments in the loading of ultracold KRb molecules into quasi-two-dimensional traps, combined with the ability to tune the ratio between elastic and loss (inelastic/reactive) collisions through application of an external electric field, are opening the door to achieving efficient evaporative cooling of reactive polar molecules. In this paper, we use Monte Carlo simulations and semianalytic models to study theoretically the experimental parameter regimes in which evaporative cooling is feasible under current trapping conditions. We investigate the effect of the anisotropic character of dipole-dipole collisions and reduced dimensionality on evaporative cooling. We also present an analysis of the experimentally relevant anti-evaporation effects that are induced by chemical reactions that take place when more than one axial vibrational state is populated.Comment: 10 pages, 7 figure

ECONOMIC IMPACTS OF CALIFORNIA'S GOLF COURSE FACILITIES IN 2000

People spent $4.350 billion at California golf course facilities in 2000. The total sales, income, and tax impacts on the state economy were$7.872 billion, $4.546 billion, and$1.370 billion in 2000. Direct sales of $4.251 billion directly supported 62,173 jobs, and , through indirect and induced sales impacts, an additional 37,609 jobs.Land Economics/Use,

Analysis of the Hirsch index's operational properties

The h-index is a relatively recent bibliometric indicator for assessing the research output of scientists, based on the publications and the corresponding citations. Due to the original characteristics of easy calculation and immediate intuitive meaning, this indicator has become very popular in the scientific community. Also, it received some criticism essentially because of its ‘‘low" accuracy. The contribution of this paper is to provide a detailed analysis of the h-index, from the point of view of the indicator operational properties. This work can be helpful to better understand the peculiarities and limits of h and avoid its misuse. Finally, we suggest an additional indicator ðf Þ that complements h with the information related to the publication age, not compromising the original simplicity and immediacy of understandin

A Survey of Quality Engineering-ManagementJournals by Bibliometric Indicators

This paper analyses some of the most popular scientific journals in the Quality field from the point of view of three bibliometric indicators: the Hirsch (h) index for journals, the total number of citations and the h-spectrum. In particular, h-spectrum is a novel tool based on h, making it possible to (i) identify a reference profile of the typical authors of a journal; (ii) compare different journals; and (iii) provide a rough indication of their ‘bibliometric positioning' in the scientific community. Results of this analysis can be helpful for guiding potential authors and members of the scientific community in the Quality Engineering/Management area. A large amount of empirical data are presented and discusse