Quadrupole Interaction of Non-diffracting Beams with Two-Level Atoms

Recently it has been shown that the quadrupole interactions can be improved significantly as the atom interacts at near resonance with the Laguerre-Gaussian (LG) mode. In this paper, we illustrate that other kinds of optical vortex can be also led to a considerable enhancement of quadrupole interaction when the atom interacts with optical modes at near resonance. The calculations are performed on an interesting situation with Cs atom, where the process is concerned with dipole-forbidden and quadrupole-allowed transitions with a convenable choice of atomic and optical mode parameters. In this direction, we show that the quadrupole transitions can be significantly enhanced and therefore they can play an interesting role and lead to new features of atom-light interaction, which can have some constructive implications in experiments.Comment: 9 pages, 10 figure

Central Arabia during the early Hellenistic period : with particular reference to the site of al-'Ayun in the area of al-Aflaj in Saudi Arabia

This thesis deals with the site of al -'Ayun in the area of al -Aflaj in Central Arabia as one of the Early Hellenistic sites in the region. The specific objectives of this work are; 1- identifying more precisely the date of the settlement, 2- exposing the nature and position of the al -'Ayun settlement in relation to the ancient trading route between the Yemen in south Arabia and Gerrha on the eastern coast of Arabia, and 3- trying to find any evidence of the relationship between the three components of the site; that is the settlement, the irrigation system, and the tumulus field.In order to achieve our objectives, and because of the rarity of information about the site, two field excavations were necessary The first excavation took place between March and May 1988, and the second excavation took place between April and May 1989. The core of this study relies on the information gathered from the excavations.To put the research in context, the thesis begins with a general introduction to the whole work. It continues with an historical survey of the ancient kingdoms of Southern Arabia, the beginning of the eastern Hellenistic world and its relation with Arabia, and the ancient inland trading routes in Arabia during the 2nd half of the 1st millennium BC. Then it looks in detail at the Hellenistic sites in eastern Arabia and those in Central Arabia. At this stage the thesis introduces the area of al- Aflaj, its geography and history, before reporting the archaeological excavations at the site of al- 'Ayun. The study is completed by an analysis of the objects found at the site i.e. pottery sherds, incense burners, stone artifacts, coins, and a seal with south Arabian script. Finally, after a general discussion and analysis of the results of the excavation, there is a discussion and the general conclusion of this thesis, which is that the settlement at al -'Ayun was an early and short -lived response to the Hellenistic stimulus to Arabian trade between the incense -producing area of the South-west and the port of Gerrha on the Gulf coast

Ground-State Cooling in Cavity Optomechanics with Unresolved Sidebands

We consider a simple cavity optomechanics and study the ground-state cooling of mechanical resonator in the quantum regime. Using the effective master equations in the linear regime, the equations of motion can be obtained for the second order moments. The steady state solutions are derived in the case where the antiresonant terms are ignored. The final mean value of phonon number is compared to the case where the antiresonant terms are included. We find that the ground-state cooling in the last case is improved. Indeed, the inclusion of the antiresonant terms makes the system able to generate a squeezed field, which is required for enhancing cooling. The variances of the resultant field are presented. Analytic calculations are presented in some appropriate regimes. Then our analytic predictions are confirmed with numerical calculations.Comment: 7 pages, 7 figure

An Empirical Investigation of the Determinants of Oman's National Savings

In this note we examine the determinants of Oman's national savings for the period 1977-2003 using the bounds testing approach to cointegration. We use the ARDL model to estimate the long run and short run determinants of national savings. Our main finding is that the current account, the urbanisation rate and the money supply exert statistically significant impacts on Oman''s national savings in the long run.

A complete and partial integrability technique of the Lorenz system

In this paper we deal with the well-known nonlinear Lorenz system that describes the deterministic chaos phenomenon. We consider an interesting problem with time-varying phenomena in quantum optics. Then we establish from the motion equations the passage to the Lorenz system. Furthermore, we show that the reduction to the third order non linear equation can be performed. Therefore, the obtained differential equation can be analytically solved in some special cases and transformed to Abel, Dufing, Painlev\'{e} and generalized Emden-Fowler equations. So, a motivating technique that permitted a complete and partial integrability of the Lorenz system is presented.Comment: 10 pages, 2 figure

THE U.S. WAR IN AFGHANISTAN: AN ASSESSMENT OF OBJECTIVES ACHIEVED AT ITS CONCLUSION

The dawn of the new millennium witnessed worldwide terrorism. In the wake of the September 11 attacks, the United States entered Afghanistan in 2001 primarily to defeat Al-Qaeda. The war turned out to be the longest overseas military campaign conducted by the United States by the time U.S. troops completed their withdrawal from Afghanistan in August 2021. Since the nature of an asymmetric war such as this one is inherently complex, it is challenging to assess how successfully the war in Afghanistan achieved U.S. objectives. This research aims to facilitate that assessment by first laying out tangible benchmarks, and thereafter gauging the war efforts according to those criteria. The research evaluates relevant terrorism statistics by examining the change in the number of terrorist incidents perpetrated by Al-Qaeda and the decimation of that group during the war. Additionally, the research analyzes the pattern of the Taliban insurgency that restored them to national power. The thesis also considers the frequency of terrorism incidents following the establishment of the U.S. Department of Homeland Security. The research empirically examines the U.S. war in Afghanistan and provides an objective assessment of the goals achieved. The research can help policymakers, think tanks, scholars, defense analysts, and military students in their respective domains by providing a strong foundation on which to draw lessons from the U.S. war in Afghanistan for future reference.Outstanding ThesisLieutenant Colonel, Pakistan ArmyApproved for public release. Distribution is unlimited

Multi-Base Chains for Faster Elliptic Curve Cryptography

This research addresses a multi-base number system (MBNS) for faster elliptic curve cryptography (ECC). The emphasis is on speeding up the main operation of ECC: scalar multiplication (tP). Mainly, it addresses the two issues of using the MBNS with ECC: deriving optimized formulas and choosing fast methods. To address the first issue, this research studies the optimized formulas (e.g., 3P, 5P) in different elliptic curve coordinate systems over prime and binary fields. For elliptic curves over prime fields, affine Weierstrass, Jacobian Weierstrass, and standard twisted Edwards coordinate systems are reviewed. For binary elliptic curves, affine, Lambda-projective, and twisted mu4-normal coordinate systems are reviewed. Additionally, whenever possible, this research derives several optimized formulas for these coordinate systems. To address the second issue, this research theoretically and experimentally studies the MBNS methods with respect to the average chain length, the average chain cost, and the average conversion cost. The reviewed MBNS methods are greedy, ternary/binary, multi-base NAF, tree-based, and rDAG-based. The emphasis is on these methods\u27 techniques to convert integer t to multi-base chains. Additionally, this research develops bucket methods that advance the MBNS methods. The experimental results show that the MBNS methods with the optimized formulas, in general, have good improvements on the performance of scalar multiplication, compared to the single-base number system methods

The factors that affect the implementation of enterprise resource planning (ERP) in the international Arab Gulf States and United States companies with special emphasis on SAP software

The primary purpose of this study was to investigate and determine the factors affecting the implementation of enterprise resource planning (ERP) in companies in the Arab Gulf States and the United States, using SAP software as an example. A random sample was selected of 150 companies in the Arab Gulf States and in the United States that had implemented an ERP system using SAP software. Of the 150 respondents, 30 were companies from the Arab Gulf States and 120 from the United States. A total of 67 questionnaires were returned, a return rate of 44.7%. The Statistical Package for the Social sciences (SPSS) was used to analyze the data. Statistical tests were conducted at the (.05) level of significance. Frequencies and percentage were used to compute and analyze the variables. Statistical measures included t -test, chi-square test, and Mann-Whitney U tests. The respondents reported that the major critical success factor for the ERP implementation was the top management support and involvement. They were most dissatisfied about the way change was managed. Most of the respondents believed the ERP implementation was successful. There were no statistically significant differences found between Arab Gulf and U.S. companies in regard to the factors that affect the implementation of an ERP system. The company size did not make any difference in the critical success factors. Most of the respondents indicated that functional reasons were the main motivation to implement the ERP system. Although the time schedule and training time for implementation were usually estimated accurately, this was less true for cost estimates. Most of the respondents indicated that they implemented an ERP system to address certain specific problems. The majority of the respondents who have already implemented an ERP system have chosen an all-in-one approach for ERP software selection and the complete system roll-out-at-once strategy. Preparatory steps included establishing a project team with a strong leader and allocating budget and resources to the implementation. The major advantage of implementing an ERP system is to have a uniform computer system across the organization. The major disadvantage is the high cost. Recommendations based on the results of the study include having a clear understanding of the objectives ERP is to serve in the company as well as of the ERP system itself and ensuring that the transition to ERP provides adequate employee training and reassurance for employee concerned about job security