Sheng Sun

© The Author 2017.Topological Weyl semimetal, a new state of quantum matter, has sparked enormous research interest recently. Possessing unique Weyl fermions in the bulk and Fermi arcs on the surface, TWSs offer a rare platform for realizing many exotic physical phenomena. TWSs can be classified into type-I that respect Lorentz symmetry and type-II that do not. Here, we directly visualize the electronic structure of MoTe 2, a recently proposed type-II TWS. Using angle-resolved photoemission spectroscopy, we unravel the unique surface Fermi arcs, in good agreement with our ab initio calculations that have nontrivial topological nature. Our work not only leads to new understandings of the unusual properties discovered in this family of compounds, but also allows for the further exploration of exotic properties and practical applications of type-II TWSs, as well as the interplay between superconductivity and their topological order.

Health-care providers in China are facing an exponential increase in HIV testing and HIV-positive patients. A total of 1101 service providers were recruited to examine attitudes toward people living with HIV/AIDS in China. Logistic regression models were used to assess factors associated with providers' attitudes toward mandatory HIV testing. Providers were most likely to endorse mandatory HIV testing for patients with high-risk behaviour and for all patients before surgery. Over 43% of providers endorsed mandatory testing for anyone admitted to hospital. Controlling for demographics, multivariate analyses indicated that providers with higher perceived risk of HIV infection at work, higher general prejudicial attitudes toward PLWHA, and previous contact with HIV patients were more likely to endorse mandatory HIV testing for anyone admitted to hospital. Results underscore the importance of implementing universal precautions in health-care settings and call attention to social and ethical issues associated with HIV/AIDS control and treatment in China.

This work attempts to respond to Tomas Aquinas' Cosmological Argument in a way that combines Set Theory with the idea of the ‘Book of Change’. The study defines the ith Cause Set on which to operate on, which leads to the ontological commitment of austerity that the ‘First Cause's Compromise with emergence’ cannot be avoided. It is argued in the present paper that the concept that ‘emergence only consists of Synchronic Emergence and Diachronic Emergence’ should be extended to a broader notion of emergence, which is made up of the two discussed elements and a third one ‘No-Boundary Emergence’ (beyond the time dimension). The article defines the concept of No-Boundary Emergence, proves why it is a type of emergence that differs from the traditional two types, and asserts that it underlies the bottom layer of the cosmos. This study describes the common feature of all emergence as communication protocols between layers. The assemblage of all emergences behaves similar to a distributed system that cannot be restricted by Gödel's theorem. The paper provides evidence (in Big Bang Cosmology, Conformal Cyclic Cosmology, Superstring Theory, Quantum Gravity) for this point of view, and notes that emergence (in the context of No-Boundary Emergence) is not only a simple scientific theory but also a progressive scientific research programme that can spontaneously grow from scientific theory based on Platonism at the expense of a degenerating shift to the ontological commitment of austerity. This paper proposes an improved model of Schrödinger Cat that provides a new explanation for quantum measurement and argues that there must be a forbidden zone of thought experiments. The study also introduces the implications of ancient Chinese thoughts (namely, the ‘Book of Change’ and Confucius). The paper comes to the conclusion that emergence (crossing the gap between ‘being’ and ‘nothing’, while ignoring the forbidden zone of thought experiments) relieves ‘cosmological insufficiency’ in the sense of Neo-Aristotelism.