Current in a Spin-orbit-coupling System

The formulae of particle current as well as spin- and angular momentum currents are studied for most spin-orbit coupling (SOC) systems. It is shown that the conventional expression of currents in some literatures are not complete for some SOC systems. The particle current in Dresselhaus system must have extra terms in additional to the conventional one, but no extra term for Rashba, Luttinger model. Further more, we also prove that the extra terms of total angular momentum appear in Rashba current in addition to conventional one.Comment: 26 page

Contract Enforcement and Family Control of Business: Evidence from China

Family control of business is prevalent in developing economies, and one of the leading theories suggests that it is a response to weak contract enforcement in such economies. In this paper, we investigate the impacts of contract enforcement on the degree of family control of business using a sample of China's private enterprises. It is found that weaker contract enforcement is associated with the higher degree of family control of business. Our results are robust to the control for omitted variables and reserve causality issues, to the adjustment for the sample attrition bias, to the use of a sub-sample, and to the inclusion of other explanations for the family control of business.Family Control of Business, Contract Enforcement, China's Private Enterprises

Compressed Sensing Based on Random Symmetric Bernoulli Matrix

The task of compressed sensing is to recover a sparse vector from a small number of linear and non-adaptive measurements, and the problem of finding a suitable measurement matrix is very important in this field. While most recent works focused on random matrices with entries drawn independently from certain probability distributions, in this paper we show that a partial random symmetric Bernoulli matrix whose entries are not independent, can be used to recover signal from observations successfully with high probability. The experimental results also show that the proposed matrix is a suitable measurement matrix.Comment: arXiv admin note: text overlap with arXiv:0902.4394 by other author