Negative-Index Metamaterials: Second-Harmonic Generation, Manley-Rowe Relations and Parametric Amplification

Second harmonic generation and optical parametric amplification in negative-index metamaterials (NIMs) are studied. The opposite directions of the wave vector and the Poynting vector in NIMs results in a "backward" phase-matching condition, causing significant changes in the Manley-Rowe relations and spatial distributions of the coupled field intensities. It is shown that absorption in NIMs can be compensated by backward optical parametric amplification. The possibility of distributed-feedback parametric oscillation with no cavity has been demonstrated. The feasibility of the generation of entangled pairs of left- and right-handed counter-propagating photons is discussed.Comment: 7 pages, 6 figure

Study of the process e+e−→3(π+π−) in the c.m. energy range 1.5–2.0 GeV with the CMD-3 detector

AbstractThe cross section of the process e+e−→3(π+π−) has been measured using a data sample of 22 pb−1 collected with the CMD-3 detector at the VEPP-2000 e+e− collider. 7956 signal events are selected in the center-of-mass energy range 1.5–2.0 GeV. The measured cross section exhibits a sharp drop near the pp¯ threshold. A first study of dynamics of six-pion production has been performed

Analysis of a Batch Arrival, Batch Service Queuing-Inventory System with Processing of Inventory While on Vacation

A single-server queuing-inventory system in which arrivals are governed by a batch Markovian arrival process and successive arrival batch sizes form a finite first-order Markov chain is considered in this paper. Service is provided in batches according to a batch Markovian service process, with consecutive service batch sizes forming a finite first-order Markov chain. A service starts for the next batch on completion of the current service, provided that inventory is available at that epoch; otherwise, there will be a delay in starting the next service. When the service of a batch is completed, the inventory decreases by 1 unit, irrespective of batch size. A control policy in which the server goes on vacation when a service process is frozen until a quorum can initiate the next batch service is proposed to ensure idle-time utilization. During the vacation, the server produces inventory (items) for future services until it hits a specified level L or until the number of customers in the system reaches a maximum service batch size N, with whichever occurring first. In the former case, a server stays idle once the processed inventory level reaches L until the number of customers reaches (or even exceeds because of batch arrival) a maximum service batch size N. The time required for processing one unit of inventory follows a phase-type distribution. In this paper, the steady-state probability vector of this infinite system is computed. The distributions of inventory processing time in a vacation cycle, idle time in a vacation cycle, and vacation cycle length are found. The effect of correlation in successive inter-arrival times and service times on performance measures for such a queuing system is illustrated with a numerical example. An optimization problem is considered. The proposed system is then compared with a queuing-inventory system without the Markov-dependent assumption on successive arrivals as well as service batch sizes using numerical examples. © 2021 by the authors. Licensee MDPI, Basel, Switzerland

On the construction of two-dimensional local-modified quasistructured grids and solving on them two-dimensional boundary value problem in the domains with curvilinear boundary

Свешников Виктор Митрофанович, д.ф.-м.н., зав. лаб., лаборатория вычислительной физики, Институт вычислительной математики и математической геофизики СО РАН (г. Новосибирск, Россия) Козырев Александр Николаевич, м. н. с., лаборатория вычислительной физики, Институт вычислительной математики и математической геофизики СО РАН (г. Новосибирск, Россия). A.N. Kozyrev, V.M. Sveshnikov Institute of Computational Mathematics and Mathematical Geophysics SB RAS (pr. Akademika Lavrentjeva 6, Novosibirsk, 630090 Russia) E-mail: [email protected],[email protected]Разработаны новые подходы к локальной модификации квазиструктурированных сеток, которые позволяют отследить неоднородности краевой задачи в расчетной области и адаптивны к криволинейным границам, а также просты в использовании и не требуют хранения большого объема данных, как это необходимо в неструктурированных сетках. Такие сетки предлагается использовать для эффективного моделирования широкого класса электрофизических приборов. Экспериментально показана необходимость локальной модификации прямоугольных сеток при расчетах в областях с криволинейной границей. Разработаны двухшаговые алгоритмы локальной модификации рассматриваемых квазиструктурированных сеток. На первом шаге проводится модификация приграничных узлов путем их сдвига на границу области по нормали к ней, а на втором – преобразование тех сеточных элементов, которые не удовлетворяют критериям качества, в качественные сеточные элементы. Разработаны специальные алгоритмы проведения таких преобразований, которые не нарушают структурированности подсеток в подобластях. Даны рекомендации по построению сеток на границах сопряжения подобластей (интерфейсе), которые содержат несогласованные сетки. Разработаны алгоритмы локальной модификации сеток на интерфейсе между подобластями, одна из которых содержит отрезок границы расчетной области. Проведены серии численных экспериментов по решению модельной задачи, результаты которых показали обоснованность предлагаемых подходов. New approaches to local modification quasistructured grids, which allow to track the inhomogeneous boundary value problems in the computational domain and adaptable to curved boundaries, as well as easy to use and does not require the storage of large amounts of data as required in unstructured grids are developed. Such grids are proposed to use for the efficient simulation of a wide class of electro physical devices. It is experimentally shown the need for a local modification of the rectangular grid in calculations in domains with curvilinear boundary. The two-step algorithms for local modifications of considered quasistructured grids are developed. On the first step modification of the near boundary nodes is carried out by the its shift along the normal to boundary and on the second step the transformation of the grid elements that do not meet the quality criteria in a quality grid elements is carried out. Special algorithms for such transformations, which do not violate the structuring subgrids in subdomains are developed. Recommendations for the construction of grids on the interface of subdomains that contain the uncoordinated grids have been done. Algorithms local modification of grids on the interface between the subdomains, one of which contains a segment of the computational domain boundaries, have been developed. The series of numerical experiments on solving a model problem are carried out. The results of numerical experiments showed the validity of the proposed approaches.Работа выполнена при финансовой поддержке РФФИ (проект № 16-01-00168