The effect of the next-nearest-neighbor (nnn) tunneling on the hard-core extended Bose–Hubbard model on square lattices is investigated. By means of the cluster mean-field theory, the ground-state phase diagrams are determined. When a modest nnn tunneling is introduced, depending on its sign, two distinct supersolid (SS) states with checkerboard crystal structures are found away from half-filing. The characters of various phase transitions out of these two SS states are discussed. In particular, for the case with kinetic frustration, the existence of a half SS phase possessing both solid and unconventional superfluid orders is established. Our work hence sheds light on the search of this interesting SS phase in real ultracold lattice gases with frustrated tunnelings.

SIPsmartER is a 6-month behavioral intervention designed using a health literacy universal precautions approach that has been found effective at reducing sugary beverage intake in rural, low socioeconomic adults. The purpose of this mixed-methods study is to determine if health literacy status influenced participants' satisfaction and perceptions of each intervention component: small group classes, interactive-voice response (IVR) calls, personal action plans and self-monitoring logs. Of the 155 participants enrolled in SIPsmartER, 105 (68%) completed an interview-administered summative evaluation including 68 high and 37 low health literate participants. The quantitative findings show participant satisfaction with each intervention component was high (i.e. classes = 9.6, IVR calls = 8.1, action plans = 8.9-9.1, logs = 8.7 on a 10-point scale) and similar across both health literacy groups. The majority of qualitative responses were positive (81.8%) and code counts were comparable between literacy groups with a few exceptions. As compared with high health literacy respondents, low health literacy respondents more frequently mentioned liking the content and length of IVR calls, liking the motivational aspects of the personal action plans, and identified numeracy issues with the self-monitoring logs. Overall, applying a health literacy universal precautions approach is an effective and acceptable strategy for both high and low health literacy groups.

The S = 1 bilinear-biquadratic Heisenberg model on anisotropic triangular lattices is investigated by several complementary methods. Our focus is on the stability of the three-sublattice spin nematic state against spatial anisotropy. We find that, deviated from the case of isotropic triangular lattice, quantum fluctuations enhance and the three-sublattice spin nematic order is reduced. In the limit of weakly coupling chains, by mapping the systems to an effective one-dimensional model, we show that the three-sublattice spin nematic order develops at infinitesimal interchain coupling. Our results provide a complete picture for smooth crossover from the triangular-lattice case to both the square-lattice and the one-dimensional limits.

We present a comprehensive numerical study on the ground state phase diagram of the two-dimensional hardcore boson extended Hubbard model with nearest ($V_1$) and next nearest neighbor ($V_2$) repulsions. In addition to the quantum solid and superfluid phases, we report the existence of striped supersolid and three-quarter (quarter) filled supersolid at commensurate density $ρ=0.75$ (0.25) due to the interplay of $V_1$ and $V_2$ interactions. The nature of three-quarter filled supersolid and the associated quantum solid will be discussed. Quantum phase transition between the two supersolids of different symmetries is observed and is clearly of first order.

The fidelity approach to the Gaussian transitions in spin-one XXZ spin chains with three different values of Ising-like anisotropy lambda is analyzed by means of the density matrix renormalization group (DMRG) technique for systems of large sizes. We find that, despite the success in the cases of lambda=2.59 and 1, the fidelity susceptibility fails to detect the Gaussian transition for lambda=0.5. Thus our results demonstrate the limitation of the fidelity susceptibility in characterizing quantum phase transitions, which was proposed recently in general frameworks.

A two-leg spin-1/2 ladder with diagonal interactions is investigated numerically. We focus our attention on the possibility of columnar dimer phase, which was recently predicted based on a reformulated bosonization theory. By using density matrix renormalization group technique and exact diagonalization method, we calculate columnar dimer order parameter, spin correlation on a rung, string order parameters, and scaled excitation gaps. Carefully using various finite-size scaling techniques, our results show no support for the existence of columnar dimer phase in the spin ladder under consideration.

The d-wave pair-pair correlation of the two-dimensional Hubbard model is investigated by the power-Lanczos method. A Jastrow-BCS type wave function is used in our variational study. By assuming a monotonic behavior of the long-range pairing correlation under Lanczos iteration, we found there is no long-range pairing order in the intermediate interaction region (U similar or equal to 10), which is consistent with the former result by the constrained-path Monte Carlo method. We also present numerical results obtained by the exact diagonalization of the 4 x 4 lattice in supporting our conclusion.

The mechanism of high-temperature superconductivity (HTS) and the correlation between the antiferromagnetic long-range order (AFLRO) and superconductivity (SC) are the central issues of the study of HTS theory. SC and AFLRO of the hole-doped two-dimensional extended t-J model are studied by the variational Monte Carlo method. The results show that SC is greatly enhanced by the long-range hopping terms t′ and t″ for the optimal and overdoped cases. The phase of coexisting SC and AFM in the t-J model disappears when t′ and t″ are included. It is concluded that the extended t-J model provides a more accurate description for HTS than the traditional t-J model does. The momentum distribution function n(k) and the shape of Fermi surface play critical roles for establishing the phase diagram of HTS materials.

We investigate the effects of the next-nearest-neighbor (t') and the third-nearest-neighbor (t") hopping terms on superconductivity correlation in the 2D hole-doped extended t-J model based on the variational Monte Carlo, mean-field calculation and exact diagonalization method. Despite the diversity of the methods employed, the results all point to a consistent conclusion: While the d-wave superconductivity correlation is slightly suppressed by t' and t" in underdoped regions, it is greatly enhanced in the optimal and overdoped regions. The optimal Tc is a result of the balance of these two opposite trends.

As the key health care providers in school settings, the school nurses' asthma management efficacy is crucial to children's health and their continued participation in school learning activities. This article describes the psychometric testing of the asthma management efficacy scale (AMES) for use with school nurses. A cross-sectional survey design was used to assess the asthma management efficacy of 60 school nurses in Taipei, Taiwan. Factor analysis resulted in four factor domains including asthma medication administration, asthma pattern identification, school management behaviour, and monitoring peak expiratory flow rate which explained 76.4% of the variance in school nurses' asthma management efficacy. The school nurses' experience in performing school asthma management activities was positively correlated to their asthma management efficacy (r=0.33, p<0.05). School nurses who had experience with the inhaled asthma medicines had significantly higher efficacy scores on the medication administration subscale (t=-2.89, p<0.01) than did the school nurses who lacked this experience. School nurses who had experience in using peak expiratory flow meters had significantly higher efficacy scores on the total AMES (t=-1.90, p<0.05) and on the monitoring peak expiratory flow rate subscale (t=-5.37, p<0.001) than the school nurses who lacked this experience. Given the need to have nurses who are well prepared to provide asthma care in school settings, implications for nursing education, practice, and further research are discussed.

The power-Lanczos (PL) method is one kind of Green's function Monte Carlo simulation, which is improved by Lanczos iterations. The ground state energies of strongly-correlated models can be evaluated by this method quite accurately. In this report, the boundary of phase separation (PS) of the two-dimensional t-J model is investigated by the power-Lanczos method and Maxwell construction. The energies are compared with the results evaluated by other methods. Our conclusion is that there is no phase separation for J/t≤0.4.

We carry out the numerical calculation of the low-energy behavior of the one-dimensional t–J model. The lowest singlet–triplet spin excitations are determined for various couplings J and densities n in the finite chain. The methods we employed in this study include the exact diagonalization for smaller lattice and power-Lanczos method for the larger lattice. The spin gap in the bulk limit is then obtained by finite-size extrapolation. We find the spin-gap region is more extensive in the phase diagram as indicated in the renormalization group analysis.

The power-Lanczos method, a Green's function Monte-Carlo simulation, is used to calculate the energies of the two-dimensional t–J model up to 122 sites. The phase boundary of phase separation of the model is then determined by the Maxwell construction. Our conclusion is that there is no phase separation for J⩽0.4.