Efficient quantum simulation of fermionic and bosonic models in trapped ions

We analyze the efficiency of quantum simulations of fermionic and bosonic models in trapped ions. In particular, we study the optimal time of entangling gates and the required number of total elementary gates. Furthermore, we exemplify these estimations in the light of quantum simulations of quantum field theories, condensed-matter physics, and quantum chemistry. Finally, we show that trapped-ion technologies are a suitable platform for implementing quantum simulations involving interacting fermionic and bosonic modes, paving the way for overcoming classical computers in the near future.Comment: 13 pages, 3 figures. Published in EPJ Quantum Technolog

Factors affecting continued use of ceramic water purifiers distributed to Tsunami-affected Communities in Sri Lanka

Objectives  There is little information about continued use of point-of-use technologies after disaster relief efforts. After the 2004 tsunami, the Red Cross distributed ceramic water filters in Sri Lanka. This study determined factors associated with filter disuse and evaluate the quality of household drinking water. Methods  A cross-sectional survey of water sources and treatment, filter use and household characteristics was administered by in-person oral interview, and household water quality was tested. Multivariable logistic regression was used to model probability of filter non-use. Results  At the time of survey, 24% of households (107/452) did not use filters; the most common reason given was breakage (42%). The most common household water sources were taps and wells. Wells were used by 45% of filter users and 28% of non-users. Of households with taps, 75% had source water Escherichia coli in the lowest World Health Organisation risk category (<1/100 ml), vs. only 30% of households reporting wells did. Tap households were approximately four times more likely to discontinue filter use than well households. Conclusion  After 2 years, 24% of households were non-users. The main factors were breakage and household water source; households with taps were more likely to stop use than households with wells. Tap water users also had higher-quality source water, suggesting that disuse is not necessarily negative and monitoring of water quality can aid decision-making about continued use. To promote continued use, disaster recovery filter distribution efforts must be joined with capacity building for long-term water monitoring, supply chains and local production

The Off-forward Quark-Quark Correlation Function

The properties of the non-forward quark-quark correlation function are examined. We derive constraints on the correlation function from the transformation properties of the fundamental fields of QCD occurring in its definition. We further develop a method to construct an ansatz for this correlator. We present the complete leading order set of generalized parton distributions in terms of the amplitudes of the ansatz. Finally we conclude that the number of independent generalized parton helicity changing distributions is four.Comment: Accepted for publication in Physical Review

Confirmation of symmetrical distributions of clinical attachment loss and tooth loss in a homogeneous Mexican adult male population

Background/purpose To ascertain whether or not clinical attachment loss and tooth loss are present with similar severity and prevalence across the two sides of the mouth in a homogeneous sample of urban male adults. Materials and methods A cross-sectional study was carried out on 161 policemen (a largely homogeneous group in terms of ethnic background, socioeconomic status, sex, occupation, and medical/dental insurance) in Campeche, Mexico. Periodontal examinations were undertaken using the Florida Probe System in a dental chair by one trained and standardized examiner (kappa ≥ 0.60) to determine clinical attachment loss and tooth loss. We examined six sites in all teeth present in the mouth (a maximum of 168 sites, no third molars). Because of correlated data between observations, McNemar (for tooth loss) and Wilcoxon (for attachment loss) signed-rank tests were used to compare right and left sites within the same patient. Results The mean age was 38.4 ± 11.0 years. The mean number of teeth present was 24.4 ± 4.6; the mean number of periodontal sites/person was 146.7 ± 27.8. All P values were ≥ 0.05 (except for attachment loss in the upper first premolars), suggesting that there were no statistically significant differences between the right and left sides for the frequency of presentation of these two conditions. Conclusion Tooth loss and attachment loss measurements largely resemble each other on both sides of the mouth