Global phase diagram of three-dimensional extended Boson Hubbard model - a continuous time Quantum Monte Carlo study

We present the global phase diagram of the extended boson Hubbard model on a simple cubic lattice by quantum Monte Carlo simulation with worm update algorithm. Four kinds of phases are supported by this model, including superfluid, supersolid, Mott, and charge density wave (CDW) states, which are identified in the phase diagram of chemical potential $\mu$ versus nearest neighbor interaction V . By changing the chemical potential, a continuous transition is found from the Mott phase to a superfluid phase without breaking the translational symmetry. For an insulating CDW state, adding particles to it gives rise to a continuous transition to a supersolid phase, while removing particles usually leads to a first-order one to either supersolid or superfluid phase. By tuning the nearest neighbor interaction, one can realize the transition between two insulating phases, Mott and CDW with the same particle density, which turns out to be of the first-order. We also demonstrate that a supersolid phase with average particle density less than 1/2 can exist in a small region of $\mu$ - V phase diagram

Amending coherence-breaking channels via unitary operations

The coherence-breaking channels play a significant role in quantum information theory. We study the coherence-breaking channels and give a method to amend the coherence-breaking channels by applying unitary operations. For given incoherent channel $\Phi$, we give necessary and sufficient conditions for the channel to be a coherence-breaking channel and amend it via unitary operations. For qubit incoherent channels $\Phi$ that are not coherence-breaking ones, we consider the mapping $\Phi\circ\Phi$ and present the conditions for coherence-breaking and channel amendment as well.Comment: 8 page

Optimizing Two Sided Promotion for IS Enabled Transportation Network: A Conditional Bayesian Learning Model

This paper investigates whether taxi apps provide attribute value for taxi driver, and how two-sided sales promotion interacted with consumer learning about attribute value to influence taxi drivers’ decision of adoption of taxi app. We propose a conditional Bayesian learning model to allow learning about multiple attributes. We find the evidence of taxi driver’s learning about attribute of app, transaction successful rate and the probability of earning cash back from app provider. We also find measurable evidence that sales promotion during product introduction has indirect effect through learning

Differences in Expression of EGFR, Ki67 and p-EPK in Oral Cavity Squamous Cell Carcinoma

Purpose: To evaluate the expression of EGFR, Ki67, and p-EPK in oral cavity and oropharyngeal cancers, and to investigate their clinical significance as prognostic markers.Methods: One hundred patients who underwent curative surgery for oral cavity or oropharyngeal squamous cell carcinoma in a Chinese People’s Liberation Army General Hospital between March 1999 and October 2010 were evaluated. The level of protein expression of EGFR, Ki67 and p-EPK was assessed by immunohistochemistry. In situ hybridization was used to detect the existence of human papillomavirus (HPV).Results: Nineteen of 75 patients with oropharyngeal cancer showed HPV-positive tumors, and two of 72 patients with oral cavity cancer showed HPV-positive tumors. EGFR and Ki67 expression was significantly higher in oral cavity cancers than in oropharyngeal cancers (p = 0.005 and p = 0.001, respectively). Loss of p-EPK occurred significantly more frequently in oral cavity cancers than in oropharyngeal cancers (p = 0.004). Overexpression of EGFR and Ki67 and loss of p-EPK were observed more frequently in HPV negative tumors. Multivariate Cox regression analysis showed that Ki67 expression had a significantly unfavorable impact on relapse free survival in oropharyngeal cancer.Conclusion: The expression levels of EGFR, Ki67, and p-EPK differ between oropharyngeal and oral cavity cancer and it may be attributed to HPV-related molecular pathogenesis. The expression of Ki67 might be an unfavorable prognostic marker for relapse-free survival in oropharyngeal cancer.Keywords: EGFR; Ki67; p-EPK; Oral cavity squamous cell carcinoma, Expression differenc