On turbulent spots in plane Poiseuille flow

Turbulence characteristics inside a turbulent spot in plume Poiseuille flow are investigated by analyzing a data base obtained from a direct numerical simulation. The spot is found to consist of two distinct regions - a turbulent area and a wave area. The flow inside the turbulent area has a strong resemblance to that found in the fully developed turbulent channel. Suitably defined mean and rms fluctuations as well as the internal shear layer structures are found to be similar to the turbulent counterpart. In the wave area, the inflexional mean spanwise profiles cause a rapid growth of oblique waves, which break down to turbulence. The breakdown process of the oblique waves is reminiscent of the secondary instability observed during transition to turbulence in channel and boundary layer flows. Other detailed characteristics associated with the Poiseuille spot are presented and are compared with experimental results

A non-abelian conjecture of Tate-Shafarevich type for hyperbolic curves

We state a conjectural criterion for identifying global integral points on a hyperbolic curve over $\mathbb{Z}$ in terms of Selmer schemes inside non-abelian cohomology functors with coefficients in $\mathbb{Q}_p$-unipotent fundamental groups. For $\mathbb{P}^1\setminus \{0,1,\infty\}$ and the complement of the origin in semi-stable elliptic curves of rank 0, we compute the local image of global Selmer schemes, which then allows us to numerically confirm our conjecture in a wide range of cases.Comment: Improvements to the exposition and numerous minor corrections throughou

From Quantum Optics to Quantum Technologies

Quantum optics is the study of the intrinsically quantum properties of light. During the second part of the 20th century experimental and theoretical progress developed together; nowadays quantum optics provides a testbed of many fundamental aspects of quantum mechanics such as coherence and quantum entanglement. Quantum optics helped trigger, both directly and indirectly, the birth of quantum technologies, whose aim is to harness non-classical quantum effects in applications from quantum key distribution to quantum computing. Quantum light remains at the heart of many of the most promising and potentially transformative quantum technologies. In this review, we celebrate the work of Sir Peter Knight and present an overview of the development of quantum optics and its impact on quantum technologies research. We describe the core theoretical tools developed to express and study the quantum properties of light, the key experimental approaches used to control, manipulate and measure such properties and their application in quantum simulation, and quantum computing.Comment: 20 pages, 3 figures, Accepted, Prog. Quant. Ele

Cognition-Based Versus Affect-Based Trust Determinants in E-Commerce: Cross-Cultural Comparison Study

The aim of this study is to examine the impact of culture on the trust determinants in e-commerce. Adopting two broad trust building foundations (cognition-based and affect-based trust) from cross-culture literature and focusing on well-established cultural constructs as groups of culture, this study develops a theoretical model of cognition-based versus affect-based e-vendor trust, and empirically tests the model using cross-cultural data. The results show that cognition-based trust determinants are more positively related to consumer trust in e- vendor in an individualist culture than in a collectivist culture. Affect-based trust determinants are more positively related to consumer trust in e-vendor in a collectivist culture than in an individualist culture. Limitation and implications for practice are also discussed

A Study of the Impact of Culture on Trust Determinants in eCommerce: A Cross-culture Comparison Study

The aim of this study is to examine the impact of culture on the trust determinants in e-commerce. The study adopts two broad trust building foundations (cognition- and affect-based trust) from cross-culture literature, focuses on one wellestablished cultural construct (i.e., individualism-collectivism) as groups of culture, develops a theoretical model of cognition-based versus affect-based e-Vendor trust, and empirically tests the model using cross-cultural data