Solitons in Trapped Bose-Einstein condensates in one-dimensional optical lattices

We use Quantum Monte Carlo simulations to show the presence and study the properties of solitons in the one dimensional soft-core bosonic Hubbard model with near neighbor interaction in traps. We show that when the half-filled Charge Density Wave (CDW) phase is doped, solitons are produced and quasi long range order established. We discuss the implications of these results for the presence and robustness of this solitonic phase in Bose-Einstein Condensates (BEC) on one dimensional optical lattices in traps and study the associated excitation spectrum. The density profile exhibits the coexistence of Mott insulator, CDW, and superfluid regions.Comment: 5 pages, Latex with figure

Magnetic and Transport Properties of a Coupled Hubbard Bilayer with Electron and Hole Doping

The single band, two dimensional Hubbard Hamiltonian has been extensively studied as a model for high temperature superconductivity. While Quantum Monte Carlo simulations within the dynamic cluster approximation are now providing considerable evidence for a d-wave superconducting state at low temperature, such a transition remains well out of reach of finite lattice simulations because of the "sign problem". We show here that a bilayer Hubbard model, in which one layer is electron doped and one layer is hole doped, can be studied to lower temperatures and exhibits an interesting signal of d-wave pairing. The results of our simulations bear resemblance to a recent report on the magnetic and superconducting properties of Ba$_2$Ca$_3$Cu$_4$O$_8$F$_2$ which contains both electron and hole doped CuO$_2$ planes. We also explore the phase diagram of bilayer models in which each sheet is at half-filling

Quantum Monte Carlo Study of an Interaction-Driven Band Insulator to Metal Transition

We study the transitions from band insulator to metal to Mott insulator in the ionic Hubbard model on a two dimensional square lattice using determinant Quantum Monte Carlo. Evaluation of the temperature dependence of the conductivity demonstrates that the metallic region extends for a finite range of interaction values. The Mott phase at strong coupling is accompanied by antiferromagnetic (AF) order. Inclusion of these intersite correlations changes the phase diagram qualitatively compared to dynamical mean field theory.Comment: 4 pages, 6 figure

Depletion induced isotropic-isotropic phase separation in suspensions of rod-like colloids

When non-adsorbing polymers are added to an isotropic suspension of rod-like colloids, the colloids effectively attract each other via depletion forces. We performed Monte Carlo simulations to study the phase diagram of such rod-polymer mixture. The colloidal rods were modelled as hard spherocylinders; the polymers were described as spheres of the same diameter as the rods. The polymers may overlap with no energy cost, while overlap of polymers and rods is forbidden. Large amounts of depletant cause phase separation of the mixture. We estimated the phase boundaries of isotropic-isotropic coexistence both, in the bulk and in confinement. To determine the phase boundaries we applied the grand canonical ensemble using successive umbrella sampling [J. Chem. Phys. 120, 10925 (2004)], and we performed a finite-size scaling analysis to estimate the location of the critical point. The results are compared with predictions of the free volume theory developed by Lekkerkerker and Stroobants [Nuovo Cimento D 16, 949 (1994)]. We also give estimates for the interfacial tension between the coexisting isotropic phases and analyse its power-law behaviour on approach of the critical point

Attractive Hubbard Model on a Honeycomb Lattice

We study the attractive fermionic Hubbard model on a honeycomb lattice using determinantal quantum Monte Carlo simulations. By increasing the interaction strength U (relative to the hopping parameter t) at half-filling and zero temperature, the system undergoes a quantum phase transition at 5.0 < U_c/t < 5.1 from a semi-metal to a phase displaying simultaneously superfluid behavior and density order. Doping away from half-filling, and increasing the interaction strength at finite but low temperature T, the system always appears to be a superfluid exhibiting a crossover between a BCS and a molecular regime. These different regimes are analyzed by studying the spectral function. The formation of pairs and the emergence of phase coherence throughout the sample are studied as U is increased and T is lowered

The 2006 July 17 Java (Indonesia) tsunami from satellite imagery and numerical modelling: A single or complex source?

The Mw 7.8 2006 July 17 earthquake off the southern coast of Java, Indonesia, has been responsible for a very large tsunami causing more than 700 casualties. The tsunami has been observed on at least 200 km of coastline in the region of Pangandaran (Wes

U.S. adolescent and adult women\u27s experiences accessing and using toilets in schools, workplaces, and public spaces: A multi-site focus group study to inform future research in bladder health

The World Health Organization recognizes access to clean and safe toilets as crucial for public health. This study explored U.S. adolescent and adult cisgender women\u27s lived experiences accessing toilets in schools, workplaces, and public spaces. As part of the Prevention of Lower Urinary Tract Symptoms (PLUS) Research Consortium, we conducted 44 focus groups with female participants (n = 360; ages 11-93). Focus groups were stratified by age (11-14, 15-17, 18-25, 26-44, 45-64, 65+) and conducted across 7 geographically diverse U.S. sites from July 2017-April 2018. Using a transdisciplinary approach, we conducted conventional qualitative coding informed by our PLUS conceptual framework and used content analysis processes to identify salient themes. Across settings, toilet access was restricted by gatekeepers (i.e., individuals who control access to toilets). In contrast, self-restricting toilet use (deciding not to use the toilet despite biologic need to urinate) was based on internalized norms to prioritize school and job responsibilities over urination. In public spaces, self-restricting use was largely in response to lack of cleanliness. Across the life course, participants perceived gender disparities in the ability to easily access public toilets. Further research is needed to determine if and how these factors impact bladder health across the life course

A prospective randomized trial of tacrolimus and prednisone versus tacrolimus, prednisone and mycophenolate mofetil in primary adult liver transplantation: A single center report

Background. Tacrolimus (TAC) and mycophenolate mofetil (MMF) are currently approved immunosuppressants for prevention of rejection in liver transplantation (LTx). They have different modes of action and toxicity profiles, but the efficacy and safety of MMF in primary liver transplantation with TAC has not been determined. Methods. An Institutional Review Board-approved, open-label, single-center, prospective randomized trial was initiated to study the efficacy and toxicity of TAC and steroids (double-drug therapy (D)) versus TAC, steroids, and MMF (triple-drug therapy (T)) in primary adult LTx recipients. Both groups of patients were started on the same doses of TAC and steroids. Patients randomized to T also received 1 gm MMF twice a day. Results. Between August 1995 and May 1998, 350 patients were enrolled at a single center-175 in the D and 175 in the T groups. All patients were followed until May 1998, with a mean follow-up of 33.8±9.1 months. Using an intention-to-treat analysis, the 1-, 2-, 3-, and 4-year patient survival was 85.1%, 81.6%, 78.6%, and 75.8%, respectively, for D and 87.4%, 85.4%, 81.3%, and 79.9%, respectively, for T. The 4-year graft survival was 70% for D and 72.1% for T. Although the rate of acute rejection in the first 3 months was significantly lower for T than for D (28% for triple vs. 38.9% for double, P=0.03), the overall rate of rejection for T at the end of 1 year was not significantly lower than for the D (38.9% triple vs. 45.2% double). The median time to the first episode of rejection was 14 days for D versus 24 days for T (P=0.008). During the study period, 38 of 175 patients in D received MMF to control ongoing acute rejection, nephrotoxicity, and/or neurotoxicity. On the other hand, 103 patients in the T discontinued MMF for infection, myelosuppression, and/or gastrointestinal disturbances. The need for corticosteroids was less after 6 months for T and the perioperative need for dialysis was lower with use of MMF. Conclusion. This final report confirms similar patient survival and graft survival up to 4 years with a trend towards fewer episodes of rejection, lower need for steroids, and better perioperative renal function. However, the complex nature of LTx patients and their posttransplantation course prevents the routine application of MMF

Experimental Limit on the Cosmic Diffuse Ultra-high Energy Neutrino Flux

We report results from 120 hours of livetime with the Goldstone Lunar Ultra-high energy neutrino Experiment (GLUE). The experiment searches for <10 ns microwave pulses from the lunar regolith, appearing in coincidence at two large radio telescopes separated by 22 km and linked by optical fiber. Such pulses would arise from subsurface electromagnetic cascades induced by interactions of >= 100 EeV neutrinos in the lunar regolith. No candidates are yet seen, and the implied limits constrain several current models for ultra-high energy neutrino fluxes.Comment: 4 pages, 4 figures, revtex4 style. New intro section, Fig. 2, Fig 4; in final PRL revie

Lifetime physical activity and breast cancer risk in the Shanghai Breast Cancer Study

Overall physical activity in adolescence and adulthood, and changes in activity over the lifespan were analysed by in-person interviews among 1459 women newly diagnosed with breast cancer and 1556 age-matched controls in urban Shanghai. Physical activity from exercise and sports, household, and transportation (walking and cycling) was assessed in adolescence (13–19 y) and adulthood (last 10 y), as was lifetime occupational activity. Logistic regression was used to estimate odds ratios (OR) and 95% confidence limits (OR (95% CL)) while controlling for confounders. Risk was reduced for exercise only in adolescence (OR = 0.84 (0.70–1.00)); exercise only in adulthood (OR = 0.68 (0.53–0.88)), and was further reduced for exercise in both adolescence and adulthood (OR = 0.47 (0.36–0.62)). Graded reductions in risk were noted with increasing years of exercise participation (OR 1–5 yrs= 0.81 (0.67–0.94); OR 6–10 yrs= 0.74 (0.59–0.93); OR 11–15 yrs= 0.55 (0.38–0.79); OR 16 + yrs= 0.40 (0.27–0.60);Ptrend,< 0.01). Lifetime occupational activity also was inversely related to risk (Ptrend< 0.01). These findings demonstrate that consistently high activity levels throughout life reduce breast cancer risk. Furthermore, they suggest that women may reduce their risk by increasing their activity levels in adulthood. © 2001 Cancer Research Campaignhttp://www.bjcancer.co