Quantum Annealing Effect on Entropic Slowing Down in Frustrated Decorated Bond System

We propose that the importance of the quantum annealing procedure to find the ground state of frustrated decorated bond systems where 'entropic slowing down' happens due to peculiar density of states. Here, we use the time dependent Schr\"odinger equation to analyze the real time dynamics of the process. It is found that the quantum annealing is very efficient comparing to the thermal annealing for searching the ground state of the systems. We analyze the mechanism of quantum annealing from a view point of adiabatic process.Comment: 2 pages, 4 figures, proceedings of ICM200

Quantum Field Induced Orderings in Fully Frustrated Ising Spin Systems

We study ordering mechanisms which are induced by the quantum fluctuation in fully frustrated Ising spin systems. Since there are many degenerated states in frustrated systems, "order by thermal disorder" often takes place due to a kind of entropy effect. To consider "order by quantum disorder" in fully frustrated Ising spin systems, we apply transverse field as quantum fluctuation. There exists a ferromagnetic correlation in each sublattice. The sublattice correlation at zero temperature is enlarged due to transverse field. The quantum fluctuation enhances the solid order at zero temperatures. This is an example of quantum field induced ordering in fully frustrated systems. We also study a case in which the transverse field induces a reentrant behavior as another type of order by quantum disorder, and compare correspondent cases in the classical systems.Comment: 3 pages, 4 figures, submitted to Proceedings of Symposia "Nanoscience and Quantum Physics

Theory and Applications of Non-Relativistic and Relativistic Turbulent Reconnection

Realistic astrophysical environments are turbulent due to the extremely high Reynolds numbers. Therefore, the theories of reconnection intended for describing astrophysical reconnection should not ignore the effects of turbulence on magnetic reconnection. Turbulence is known to change the nature of many physical processes dramatically and in this review we claim that magnetic reconnection is not an exception. We stress that not only astrophysical turbulence is ubiquitous, but also magnetic reconnection itself induces turbulence. Thus turbulence must be accounted for in any realistic astrophysical reconnection setup. We argue that due to the similarities of MHD turbulence in relativistic and non-relativistic cases the theory of magnetic reconnection developed for the non-relativistic case can be extended to the relativistic case and we provide numerical simulations that support this conjecture. We also provide quantitative comparisons of the theoretical predictions and results of numerical experiments, including the situations when turbulent reconnection is self-driven, i.e. the turbulence in the system is generated by the reconnection process itself. We show how turbulent reconnection entails the violation of magnetic flux freezing, the conclusion that has really far reaching consequences for many realistically turbulent astrophysical environments. In addition, we consider observational testing of turbulent reconnection as well as numerous implications of the theory. The former includes the Sun and solar wind reconnection, while the latter include the process of reconnection diffusion induced by turbulent reconnection, the acceleration of energetic particles, bursts of turbulent reconnection related to black hole sources as well as gamma ray bursts. Finally, we explain why turbulent reconnection cannot be explained by turbulent resistivity or derived through the mean field approach.Comment: 66 pages, 24 figures, a chapter of the book "Magnetic Reconnection - Concepts and Applications", editors W. Gonzalez, E. N. Parke

Designs and Production Technology of Sickle Elements in Late Neolithic Wadi Ziqlab, Northern Jordan

Abstract : This paper examines sickle elements from Late Neolithic agricultural settlements in the southern Levant with a particular focus on the tool morphology and the production technology. The results of the examination suggest that two Late Neolithic farmsteads in Wadi Ziqlab share greater morphological similarity of sickle elements than do other sites of the same cultural group (the Wadi Rabah culture) in other regions. However, the technological analyses of sickle elements suggest that the two farmsteads in Wadi Ziqlab had different patterns in some technological practices during the production processes, including the blank production, the extent of retouch, backing technique, and possibly the sequence of retouching processes. Based on these results, the subsequent discussion aims at explaining the standardized design of sickle elements and their varied production technology observed in Wadi Ziqlab, particularly focusing on several factors, including chronology, geography, the mechanical functions of sickle elements, and the mechanical logistics of production technology. After examining these factors, I will briefly discuss social contexts that may have been related to the production practices of sickle elements.Résumé : Cette étude examine les éléments de faucille des établissements agricoles du Néolithique Récent dans le Sud du Levant ; l 'attention se porte plus particulièrement sur la morphologie des outils et la technologie de production. Les résultats de l'analyse suggèrent que les deux établissements du Wadi Ziqlab présentent une plus grande similarité morphologique des éléments de faucille que ne le font dans les autres régions les sites de même culture (Wadi Rabah). Les analyses technologiques des éléments de faucille suggèrent pourtant que les deux fermes du Wadi Ziqlab usaient de modes différents dans leurs technologies que ce soient celle de la production et de la sélection du support (éclats vs lames), l'étendue de la retouche et la retouche (denticulation, dos, troncature). En se fondant sur ces résultats, la discussion cherche à comprendre comment s 'est effectuée à la fois la standardisation des éléments de faucille et la variation dans les techniques de production observée sur les sites du Wadi Ziqlab. Plusieurs facteurs sont pris en compte : chronologie, géographie, fonctions mécaniques des éléments de faucilles, et logiques mécaniques des technologies de production. Après l 'examen de ces facteurs, une brève discussion porte sur les contextes sociaux qui peuvent avoir exercé une influence sur les mécanismes de production d'éléments de faucille.Kadowaki Seiji. Designs and Production Technology of Sickle Elements in Late Neolithic Wadi Ziqlab, Northern Jordan . In: Paléorient, 2005, vol. 31, n°2. pp. 69-85