Mott-Hubbard Transition of Bosons in Optical Lattices with Three-body Interactions

In this paper, the quantum phase transition between superfluid state and Mott-insulator state is studied based on an extended Bose-Hubbard model with two- and three-body on-site interactions. By employing the mean-field approximation we find the extension of the insulating 'lobes' and the existence of a fixed point in three dimensional phase space. We investigate the link between experimental parameters and theoretical variables. The possibility to obverse our results through some experimental effects in optically trapped Bose-Einstein Condensates(BEC) is also discussed.Comment: 7 pages, 4 figures; to be appear in Phys. Rev.

Anomalous Spin Dynamics of Hubbard Model on Honeycomb Lattices

In this paper, the honeycomb Hubbard model in optical lattices is investigated using O(3) non-linear sigma model. A possible quantum non-magnetic insulator in a narrow parameter region is found near the metal-insulator transition. We study the corresponding dynamics of magnetic properties, and find that the narrow region could be widened by hole doping.Comment: 9 pages, 12 figure

Fractal analysis of effective thermal conductivity for three-phase (unsaturated) porous media

2009-2010 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

Coexistence of Itinerant Electrons and Local Moments in Iron-Based Superconductors

In view of the recent experimental facts in the iron-pnictides, we make a proposal that the itinerant electrons and local moments are simultaneously present in such multiband materials. We study a minimal model composed of coupled itinerant electrons and local moments to illustrate how a consistent explanation of the experimental measurements can be obtained in the leading order approximation. In this mean-field approach, the spin-density-wave (SDW) order and superconducting pairing of the itinerant electrons are not directly driven by the Fermi surface nesting, but are mainly induced by their coupling to the local moments. The presence of the local moments as independent degrees of freedom naturally provides strong pairing strength for superconductivity and also explains the normal-state linear-temperature magnetic susceptibility above the SDW transition temperature. We show that this simple model is supported by various anomalous magnetic properties and isotope effect which are in quantitative agreement with experiments.Comment: 7 pages, 4 figures; an expanded versio

Quench dynamics of topological quantum phase transition in Wen-plaquette model

We study the quench dynamics of the topological quantum phase transition in the two-dimensional transverse Wen-plaquette model, which has a phase transition from a Z2 topologically ordered to a spin-polarized state. By mapping the Wen-plaquette model onto a one-dimensional quantum Ising model, we calculate the expectation value of the plaquette operator Fi during a slowly quenching process from a topologically ordered state. A logarithmic scaling law of quench dynamics near the quantum phase transition is found, which is analogous to the well-known static critical behavior of the specific heat in the one-dimensional quantum Ising model.Comment: 8 pages, 5 figures,add new conten

Development and Application of a Diaphragm Micro-Pump with Piezoelectric Device

In this study, a new type of thin, compact, and light weighed diaphragm micro-pump has been successfully developed to actuate the liquid by the vibration of a diaphragm. The micro-diaphragm pump with two valves is fabricated in an aluminum case by using highly accurate CNC machine, and the cross-section dimension is 5mm x 8mm. Both valves and diaphragm are manufactured from PDMS. The amplitude of vibration by a piezoelectric device produces an oscillating flow which may change the chamber volume by changing the curvature of a diaphragm. Several experimental set-ups for performance test in a single micro-diaphragm pump, isothermal flow open system, and a closed liquid cooling system is designed and implemented. The performance of one-side actuating micro-diaphragm pump is affected by the design of check valves, diaphragm, piezoelectric device, chamber volume, input voltage and frequency. The measured maximum flow rate of present design is 72 ml/min at zero total pump head in the range of operation frequency 70-180 Hz.Comment: Submitted on behalf of EDA Publishing Association (http://irevues.inist.fr/EDA-Publishing

Oil and Gas Air Heaters

Most conventional air heaters adopt indirect heat transfer, which uses combustion gases to indirectly heat fresh air by heating surfaces to generate hot air used for material drying and dehumidification. We call them indirect air heaters. However, they have a higher manufacturing cost and lower thermal efficiency, especially when high temperature air is needed. For this reason, a direct air heater applicable for or feed and industrial raw products is put forward, which has advantages such as less production cost, smaller dimensions and higher thermal efficiency. Their design, working principles, characteristics, structure and applications are presented in this article, and brief comparisons are made between the indirect and direct air heater. Finally, the relation of hot-air temperature, oil or gas consumption and fresh airflow is determined based on energy equilibrium

Study of color suppressed modes B0→Dˉ(∗)0η(′)B^0 \to \bar D^{(*)0} \eta^{(\prime)}

The color suppressed modes $B^0 \to \bar D^{(*)0} \eta^{(\prime)}$ are analyzed in perturbative QCD approach. We find that the dominant contribution is from the non-factorizable diagrams. The branching ratios calculated in our approach for $B^0 \to \bar D^{(*)0} \eta$ agree with current experiments. By neglecting the gluonic contribution, we predict the branching ratios of $B^0 \to \bar D^{(*)0} \eta'$ are at the comparable size of $B^0 \to \bar D^{(*)0} \pi^0$, but smaller than that of $B^0 \to \bar D^{(*)0} \eta$.Comment: revtex, 5 pages, axodraw.st

A prognostic survival model for women diagnosed with invasive breast cancer in Queensland, Australia.

PURPOSE: Prognostic models can help inform patients on the future course of their cancer and assist the decision making of clinicians and patients in respect to management and treatment of the cancer. In contrast to previous studies considering survival following treatment, this study aimed to develop a prognostic model to quantify breast cancer-specific survival at the time of diagnosis. METHODS: A large (n = 3323), population-based prospective cohort of women were diagnosed with invasive breast cancer in Queensland, Australia between 2010 and 2013, and followed up to December 2018. Data were collected through a validated semi-structured telephone interview and a self-administered questionnaire, along with data linkage to the Queensland Cancer Register and additional extraction from medical records. Flexible parametric survival models, with multiple imputation to deal with missing data, were used. RESULTS: Key factors identified as being predictive of poorer survival included more advanced stage at diagnosis, higher tumour grade, "triple negative" breast cancers, and being symptom-detected rather than screen detected. The Harrell's C-statistic for the final predictive model was 0.84 (95% CI 0.82, 0.87), while the area under the ROC curve for 5-year mortality was 0.87. The final model explained about 36% of the variation in survival, with stage at diagnosis alone explaining 26% of the variation. CONCLUSIONS: In addition to confirming the prognostic importance of stage, grade and clinical subtype, these results highlighted the independent survival benefit of breast cancers diagnosed through screening, although lead and length time bias should be considered. Understanding what additional factors contribute to the substantial unexplained variation in survival outcomes remains an important objective