Classification of the phases of 1D spin chains with commuting Hamiltonians

We consider the class of spin Hamiltonians on a 1D chain with periodic boundary conditions that are (i) translational invariant, (ii) commuting and (iii) scale invariant, where by the latter we mean that the ground state degeneracy is independent of the system size. We correspond a directed graph to a Hamiltonian of this form and show that the structure of its ground space can be read from the cycles of the graph. We show that the ground state degeneracy is the only parameter that distinguishes the phases of these Hamiltonians. Our main tool in this paper is the idea of Bravyi and Vyalyi (2005) in using the representation theory of finite dimensional C^*-algebras to study commuting Hamiltonians.Comment: 8 pages, improved readability, added exampl

Regioselective iodination of aryl amines using 1,4-dibenzyl-1,4-diazoniabicyclo [2.2.2] octane dichloroiodate in solution and under solvent-free conditions

1,4-Dibenzyl-1,4-diazoniabicyclo[2.2.2]octane dichloroiodate is an efficient and regioselective reagent for iodination of aryl amines. A wide variety of aryl amines in reaction with this reagent afforded regioselectively iodinated products. The iodination reaction can be carried out in solution or under solvent-free condition at room temperature. KEY WORDS:  Regioselective iodination, Aryl amines, 1,4-Dibenzyl-1,4-diazoniabicyclo [2.2.2] octane dichloroiodate,  Solvent-free conditions Bull. Chem. Soc. Ethiop. 2015, 29(1), 157-162DOI: http://dx.doi.org/10.4314/bcse.v29i1.1

Approximating the Set of Separable States Using the Positive Partial Transpose Test

The positive partial transpose test is one of the main criteria for detecting entanglement, and the set of states with positive partial transpose is considered as an approximation of the set of separable states. However, we do not know to what extent this criterion, as well as the approximation, are efficient. In this paper, we show that the positive partial transpose test gives no bound on the distance of a density matrix from separable states. More precisely, we prove that, as the dimension of the space tends to infinity, the maximum trace distance of a positive partial transpose state from separable states tends to 1. Using similar techniques, we show that the same result holds for other well-known separability criteria such as reduction criterion, majorization criterion and symmetric extension criterion. We also bring an evidence that the sets of positive partial transpose states and separable states have totally different shapes.Comment: 12 pages, published versio

Diameter and Chirality Dependence of Exciton Properties in Carbon Nanotubes

We calculate the diameter and chirality dependences of the binding energies, sizes, and bright-dark splittings of excitons in semiconducting single-wall carbon nanotubes (SWNTs). Using results and insights from {\it ab initio} calculations, we employ a symmetry-based, variational method based on the effective-mass and envelope-function approximations using tight-binding wavefunctions. Binding energies and spatial extents show a leading dependence with diameter as $1/d$ and $d$, respectively, with chirality corrections providing a spread of roughly 20% with a strong family behavior. Bright-dark exciton splittings show a $1/d^2$ leading dependence. We provide analytical expressions for the binding energies, sizes, and splittings that should be useful to guide future experiments

Local Quantum Measurement and No-Signaling Imply Quantum Correlations

We show that, assuming that quantum mechanics holds locally, the finite speed of information is the principle that limits all possible correlations between distant parties to be quantum mechanical as well. Local quantum mechanics means that a Hilbert space is assigned to each party, and then all local positive-operator-valued measurements are (in principle) available; however, the joint system is not necessarily described by a Hilbert space. In particular, we do not assume the tensor product formalism between the joint systems. Our result shows that if any experiment would give nonlocal correlations beyond quantum mechanics, quantum theory would be invalidated even locally.Comment: Published version. 5 pages, 1 figure

Studying three management skills among midwifery managers of Iranian universities of medical sciences in 2015

Introduction: Nowadays, for organizational success, managers should accept multiple roles that each requires trainings for specific skills. This issue especially is much more important in health care systems that are responsible for improving the health of the society. Therefore, this study was aimed to determine three managerial skills among midwifery managers Iranian Medical Sciences Universities.Method: This study was descriptive and data collection method was cross-sectional. The subjects in this study included members of the Board of Midwifery and Reproductive Health, bachelors of midwifery in the field of health care and members of midwifery faculty from eight Iranian universities of medical sciences. Collecting information was performed through demographic characteristics questionnaire and triple skills of management researcher-made questionnaire. Validity and reliability were determined through content validity and Cronbach's alpha coefficient of α = 0.88 and test results were evaluated and analyzed by inferential statistics (ANOVA, Kruskal-Wallis test) which p < 0.05 was considered as the significant level.Results: The results of this study showed that in the field of knowledge, managers prioritized the skills as follows: the human-communicational skills (MR =69.05), technical skills (MR =50.31) and theoretical-cognitive skills (MR =47.57). Also prioritization of skills from the perspective of the study population in the field of importance was human-communicational skills (MR =82.23), technical skills (MR =76.57) and theoretical-cognitive skills (MR =75.47).Discussion: According to the results of this study, the importance of humancommunicational skills in all the hierarchy and categories of management is one of the essential tasks of managers for promoting organizations toward the achievement of their goals efficiently and effectively.Keywords: Managers, Management Skills, Human Skills, Midwive