Vector chiral states in low-dimensional quantum spin systems

A class of exact spin ground states with nonzero averages of vector spin chirality, $$, is presented. It is obtained by applying non-uniform O(2) rotations of spin operators in the XY plane on the SU(2)-invariant Affleck-Kennedy-Lieb-Tasaki (AKLT) states and their parent Hamiltonians. Excitation energies of the new ground states are studied with the use of single-mode approximation in one dimension for S=1. The excitation gap remains robust. Construction of chiral AKLT states is shown to be possible in higher dimensions. We also present a general idea to produce vector chirality-condensed ground states as non-uniform O(2) rotations of the non-chiral parent states. Dzyaloshinskii-Moriya interaction is shown to imply non-zero spin chirality.Comment: 4 pages, 1 figur

Coupling of phonons and spin waves in triangular antiferromagnet

We investigate the influence of the spin-phonon coupling in the triangular antiferromagnet where the coupling is of the exchange-striction type. The magnon dispersion is shown to be modified significantly at wave vector (2pi,0) and its symmetry-related points, exhibiting a roton-like minimum and an eventual instability in the dispersion. Various correlation functions such as equal-time phonon correlation, spin-spin correlation, and local magnetization are calculated in the presence of the coupling.Comment: 6 pages, 5 figures; references added, minor text revisions, submitted to PR

Chiral spin states in the pyrochlore Heisenberg magnet: Fermionic mean-field theory and variational Monte Carlo calculations

Fermionic mean-field theory and variational Monte Carlo calculations are employed to shed light on the possible uniform ground states of the Heisenberg model on the pyrochlore lattice. Among the various flux configurations, we find the chiral spin states carrying \pm pi/2 flux through each triangular face to be the most stable both within the mean-field theory and the projected wave-function studies. Properties of the spin-spin correlation function and the chirality order parameter are calculated for the projected wave functions. Mean-field band structures are examined.Comment: 4 pages, 3 figures, minor text revisions, references adde

The church as the body of Christ: Ecclesiology in Ephesians in the Light of Eph 1:22-23

This thesis concentrates on clarifying the significance of αωμα αύτού in Eph 1:22-23, in order to investigate the ecclesiology in Ephesians. In this letter the "body of Christ" is presented not only as a central designation of the church but also as the pre-eminent image for it. Chapter 1 carries out preliminary work for interpreting the passage; that is, it examines the background of the three key words in the passage – κεϕαλη, σωμα, and πληρωμα. Several candidates for each have been cogently suggested by scholars and are investigated as to whether they are influential, and what is the extent of any such influence. Chapter 2 pays attention to Eph 1:22 which includes several words and phrases of great consequence, and which is informative regarding the meaning of σωμα αυτσυ. This chapter looks into not only the use and the significance of Ps 8:6 in v.22a, but also the meaning of δίδωμι, η κεϕαλη ύπερ παυτα. The main concern of this inquiry is to understand how this verse, especially the concept κεϕαλη is associated with σωμα αντσυ. Chapter 3 focuses on the phrase σωμα αυτου itself in Eph 1:23a. This chapter first considers what insight into its meaning is given by the context and by the phrase itself. It then further considers several prominent σωμα-passages (i.e. Eph 2:14-18, 4:1-16, and 5:22-33), and infers the significance of the phrase from implications which these passages provide. These passages imply that the phrase is involved in the two major images, "husband/wife" and "head/body”, and conveys various senses concerning the relationship of Christ and the church. Chapter 4 proceeds to interpret Eph l:23b-c, which includes the second definition of the church, viz. πληρωμα [του Xρίστσυ]. This chapter first deals with four exegetical problems, then attempts to clarify the sense of the "fullness of Christ" and of the cosmic filling of Christ. The purpose of this is to examine how the passage, especially the term πληρωμα, discloses the meaning of αωμα αυτου. This study comes to the conclusion that the key phrase conveys the special unity of the church which it knows with the enthroned Christ, who is her sovereign lord, representative, archetype, supplier, and husband in the marriage relationship

The Effect of Institutional Dimensions and Cultural Dimensions on the Level of Entrepreneurial Activity Across Countries

Entrepreneurship research is becoming more critical to policymakers and scholars around the world. However, few scholars have explored the effect of national culture or institutions on the entrepreneurial activity using cross-national data. Furthermore, most previous scholars have been limited to formal institutions as a theoretical structure to explore the entrepreneurial activity across countries. It is crucial to include formal, informal institutions and culture to better understand about how much or why entrepreneurial activity differs across countries. To fill this gap, this study investigates how national culture and institutions impact the level of entrepreneurial activity across 30 countries using cross-national dataset from the World Bank Dataset, the GEM report, and Hofstede’s cultural dimensions during the 5-year period from 2009 to 2013. Moreover, this study used two distinct measures of the level of entrepreneurial activity as dependent variables (i.e., the rate of new start-up companies and Total Entrepreneurial Activity). The results showed that individualism, uncertainty avoidance, power distance, and long-term orientation are essential for explaining the level of entrepreneurial activity across countries. However, the results indicated that only one of the regulative dimensions (i.e., the number of start-up procedures) was significantly related to the level of entrepreneurial activity. Therefore, the finding of this study concludes that national culture may play more important roles than institutions regarding the level of entrepreneurial activity across countries

An analysis of land use change using GIS and spatial analysis :a case study of the Seoul metropolitan region perimeter

PhD ThesisThis thesis is concerned with analytical and technical capability in using Geographical Information Systems (GIS) and spatial analysis as relevant to the policy challenge of urban fringe management, taking as a case study the Seoul Metropolitan Region Perimeter. The primary purpose of this study is to analyse land use change using the tools of GIS and Spatial Analysis as a spatial decision support system for the task of managing the fragmented development of the urban fringe caused by the policy changes introduced by the Korean government in 1994. The case study analysed in this research shows whether GIS and spatial analysis can be applied to manage and monitor land use change in the urban fringe area at a very detailed level using municipal parcel data which occupies about 80% of administrative affairs, especially at the local government level in Korea. The major determinants of land use change in the study area have been investigated in an attempt to enhance the knowledge of how to provide decision support information for local government in Korea using GIS and spatial analysis. The results of the analysis represent the distribution of land use change from 1994 to 1998, the distribution of parcels with more than 50% of their neighbours in urban use and the transition probability of land use within a GIS, etc. The analysis using GIS and spatial analysis proved to be effective ones when providing the information base for modelling land use change in the urban fringe of the Seoul Metropolitan Region in Korea, to enable informed decisions to be made about land management policies in such areas. The lesson which could be drawn from this study is that a GIS and spatial analysis capacity is quite useful for local government to understand where and why land use change is concentrated, how the pattern of land use has changed, and which areas are susceptible to land use change. This study represented the results of analysis as a map, showed the significant patterns of land use change in the study area, displayed the relationship between neighbouring land use and the pattern of land use change, and suggested the transition probability of land use in the urban fringe in the future. Better understanding of the results may enhance the capability of local government to predict future land use change dynamics and devise more effective land use management strategies. This study brings a new approach to understanding the evolution of development patterns using the methods of combining spatial statistical analysis techniques with GIS application at site level