Non trivial generalizations of the Schwinger pair production result II

It is suggested that Schwinger's (1951) vacuum persistence probability against pair production by an intense but constant electric field is a very good approximation to the corresponding quantity if the field does not vary appreciably over distances less than m/e/E/5 pagesComment: 5 page

Enhanced four-wave mixing via elimination of inhomogeneous broadening by coherent driving of quantum transition with control fields

We show that atoms from wide velocity interval can be concurrently involved in Doppler-free two-photon resonant far from frequency degenerate four-wave mixing with the aid of auxiliary electromagnetic field. This gives rise to substantial enhancement of the output radiation generated in optically thick medium. Numerical illustrations addressed to typical experimental conditions are given.Comment: LaTeX2e, hyperref, 7 pages, 5 figures, to appear in PRA 1 august 200

Pair creation in transport equations using the equal-time Wigner function

Based on the equal-time Wigner function for the Klein-Gordon field, we discuss analytically the mechanism of pair creation in a classical electromagnetic field including back-reaction. It is shown that the equations of motion for the Wigner function can be reduced to a variable-frequency oscillator. The pair-creation rate results then from a calculation analogous to barrier penetration in nonrelativistic quantum mechanics. The Wigner function allows one to utilize this treatment for the formulation of an effective transport theory for the back-reaction problem with a pair-creation source term including Bose enhancement.Comment: 19 pages, LaTeX, UFTP 316/199

Organization of the channel-switching process in parallel computer systems based on a matrix optical switch

After a classification and analysis of electronic and optoelectronic switching devices, the design principles and structure of a matrix optical switch is described. The switching and pair-exclusion operations in this type of switch are examined, and a method for the optical switching of communication channels is elaborated. Finally, attention is given to the structural organization of a parallel computer system with a matrix optical switch

Magnetoelectric response of multiferroic BiFeO3 and related materials

We present a first-principles scheme for computing the magnetoelectric response of multiferroics. We apply our method to BiFeO3 (BFO) and related compounds in which Fe is substituted by other magnetic species. We show that under certain relevant conditions -- i.e., in absence of incommensurate spin modulation, as in BFO thin films and some BFO-based solid solutions -- these materials display a large linear magnetoelectric response. Our calculations reveal the atomistic origin of the coupling and allow us to identify the most promising strategies to enhance it.Comment: 4 pages with 1 figure embedded. More information at http://www.icmab.es/dmmis/leem/jorg

Schwinger Pair Production in dS_2 and AdS_2

We study Schwinger pair production in scalar QED from a uniform electric field in dS_2 with scalar curvature R_{dS} = 2 H^2 and in AdS_2 with R_{AdS} = - 2 K^2. With suitable boundary conditions, we find that the pair-production rate is the same analytic function of the scalar curvature in both cases.Comment: RevTex 6 pages, no figure; replaced by the version published in PR

Towards Identifying and closing Gaps in Assurance of autonomous Road vehicleS - a collection of Technical Notes Part 1

This report provides an introduction and overview of the Technical Topic Notes (TTNs) produced in the Towards Identifying and closing Gaps in Assurance of autonomous Road vehicleS (Tigars) project. These notes aim to support the development and evaluation of autonomous vehicles. Part 1 addresses: Assurance-overview and issues, Resilience and Safety Requirements, Open Systems Perspective and Formal Verification and Static Analysis of ML Systems. Part 2: Simulation and Dynamic Testing, Defence in Depth and Diversity, Security-Informed Safety Analysis, Standards and Guidelines

Parameter selection for the supply system in a Pilger mill

The braking chamber in the supply system of a Pilger pipe mill is modernized. The influence of constant and variable parameters of the supply system on braking is studied. © 2013 Allerton Press, Inc

Ефективність здійснення оперативної закупки підрозділами кримінальної поліції за сучасного нормативно-правового регулювання

Legal regulation of operative procurement within operative and search and criminal procedural legislation has been highlighted. Special attention is paid to the main contradictions related to legal conflicts and their impact on the effectiveness of implementing operative procurement by the units of criminal police. The need of additional research of operative procurement with appropriate amendments to the legislation and departmental regulatory base has been grounded. The author has stated on the need for adjustments of approaches to conduct operative procurement because of the changes in criminal environment. It has been stressed that only a comprehensive application of capabilities will make it possible to achieve the goals of criminal procedure and bring the perpetrators to justice. Further ignoring of the stated situation without appropriate amendments to the legislation will be not just reflected on criminal statistics, but can cost more than one life, since an armed conflict in eastern Ukraine flooded illegal market with arms and ammunition. Special attention is paid to the need for revision of the practice of conducting operative procurement through the use of modern information technologies and the Internet by criminals. It has been indicated that the adoption of the new Criminal Procedural Code, because of a number of factors led to the loss of operative and search activities and their initiative and offensive, which is unacceptable, because the vast majority of criminal proceedings being investigated by investigative units, is the result of operative developments. Therefore, position on combining procedural, operative and search means, but preserving their main qualities and with the full agreement is fully justified, otherwise the successful conduction of operative procurement with documenting criminal fact threatens not only the judicial perspective of the criminal proceedings, but also the life and health of people who were involved in the event.Висвітлено нормативно-правове регулювання оперативної закупки в оперативно-розшуковому та кримінальному процесуальному законодавстві. Акцентовано увагу на основних суперечностях, пов’язаних із правовими колізіями, та їх впливі на ефективність застосування оперативної закупки підрозділами кримінальної поліції. Обґрунтовано необхідність додаткового дослідження оперативної закупки з внесенням відповідних змін до законодавства та відомчої нормативно-правової бази. Указано на необхідність коригування підходів до проведення оперативної закупки через зміни злочинного середовища