Bright squeezed vacuum in a nonlinear interferometer: frequency/temporal Schmidt-mode description

Control over the spectral properties of the bright squeezed vacuum (BSV), a highly multimode non-classical macroscopic state of light that can be generated through high-gain parametric down conversion, is crucial for many applications. In particular, in several recent experiments BSV is generated in a strongly pumped SU(1,1) interferometer to achieve phase supersensitivity, perform broadband homodyne detection, or tailor the frequency spectrum of squeezed light. In this work, we present an analytical approach to the theoretical description of BSV in the frequency domain based on the Bloch-Messiah reduction and the Schmidt-mode formalism. As a special case we consider a strongly pumped SU(1,1) interferometer. We show that different moments of the radiation at its output depend on the phase, dispersion and the parametric gain in a nontrivial way, thereby providing additional insights on the capabilities of nonlinear interferometers. In particular, a dramatic change in the spectrum occurs as the parametric gain increases

Factorization of equations with dominating higher partial derivative

We present necessary and sufficient conditions for the factorization of equations with dominating partial derivatives and illustrate the possibility of using our results by examples of two forms of equations of the second and third orders. © 2014 Pleiades Publishing, Ltd

Projective filtering of a single spatial radiation eigenmode

Lossless filtering of a single coherent (Schmidt) mode from spatially multimode radiation is a problem crucial for optics in general and for quantum optics in particular. It becomes especially important in the case of nonclassical light that is fragile to optical losses. An example is bright squeezed vacuum generated via high-gain parametric down conversion or four-wave mixing. Its highly multiphoton and multimode structure offers a huge increase in the information capacity provided that each mode can be addressed separately. However, the nonclassical signature of bright squeezed vacuum, photon-number correlations, are highly susceptible to losses. Here we demonstrate lossless filtering of a single spatial Schmidt mode by projecting the spatial spectrum of bright squeezed vacuum on the eigenmode of a single-mode fiber. Moreover, we show that the first Schmidt mode can be captured by simply maximizing the fiber-coupled intensity. Importantly, the projection operation does not affect the targeted mode and leaves it usable for further applications.Comment: 10 pages, 9 figure

Assessment of quality and safety of pork treated with low-temperature atmospheric-pressure plasma

It is known that processing methods ensuring partial or full microbial inactivation are quite limited. Therefore, it is of great interest to develop technique and technologies allowing the effective action on microorganisms without a significant influence on product properties. The use of cold plasma can be one of the promising methods of meat product treatment by cold sterilization. The present work examines a possibility of chilled meat treatment with low-temperature atmospheric-pressure plasma to increase its stability to microbial spoilage and extend shelf life. To obtain low temperature plasma, the equipment developed by the designing department “Plasmamed” was used. Chilled meat was treated with low-temperature atmospheric-pressure argon plasma for 5, 10, 20 and 30 min. Samples were stored at a temperature of 2–4 °C for 10 days. Organoleptic indices, moisture weight fraction, changes in pH and water activity were analyzed before treatment and during storage. Sanitary microbiological analyses were carried out by the following indicators: quantity of mesophilic aerobic and facultative anaerobic microorganisms (QMAFAnM), the presence and quantity of coliforms, Salmonella, Escherichia coli, Listeria monocytogenes, Proteus. It was shown that meat cold treatment with argon plasma inhibited the development of mesophilic microorganisms. The colony forming units detected in the samples after ten days of storage were determined by the duration of exposure to plasma. It was proved that meat treatment for 15 and 30 min had the bactericidal effect and facilitated an improvement in meat color during storage. The organoleptic indices of the samples treated with plasma corresponded to the requirements of standards and approved consumer characteristics

Calculation of inductances of stator’s windings in induction motor with ring windings by «ANSYS» and «ANSYS Maxwell»

In the paper algorithm for inductances calculation of stator windings in an induction motor with ring windings by «ANSYS» and «ANSYS Maxwell» is considered. The work presents the order of setting of the parameters required for the calculation in the model. In the course of the work, the basic expressions used by the programs for deriving matrices of inductances are determined, the results are analyzed, and recommendations are given to the user for carrying out such calculations.В статье рассматривается алгоритм расчета индуктивностей обмоток статора в асинхронном двигателе с кольцевыми обмотками с помощью прикладных программных пакетов «ANSYS» и «ANSYS Maxwell». В работе указывается порядок задания параметров в модели, необходимых для расчета. В ходе работы определяются основные выражения, используемые программами для вывода матриц индуктивностей, анализируются полученные результаты

The methodology of MMF calculation in magnetic circuit of induction motor by "ANSYS Maxwell"

In the paper the methodology of MMF calculation in magnetic circuit of induction motor by "ANSYS Maxwell"is considered. The calculation is based on the use of the total current law. The magnetic circuit of the induction motor is divided into several sections: stator tooth, rotor tooth, air gap, stator yoke and rotor yoke. Each section of the circuit is analyzed separately. The calculation result obtained using "ANSYS Maxwell"is compared with the results of the classical methodology. © Published under licence by IOP Publishing Ltd

Reproductive ability of black currant cultivars after pollen cryopreservation in liquid nitrogen

Background. Studying the reproductive ability of black currant cultivars after long-term cryopreservation of their pollen in liquid nitrogen is very important for plant diversity conservation and for the effectiveness of breeding efforts.Materials and methods. Five black currant cultivars served as the material for the research. The viability of black currant pollen after cryopreservation in liquid nitrogen was analyzed. Pollen viability was tested on an artificial medium containing 10% of sucrose and 0.8% of agar. The viability of pollen was tested on the black currant collection at Pushkin and Pavlovsk Laboratories of VIR. The cultivar ‘Andreevskaya’ (k-15630) was pollinated with pollen stored for one year in liquid nitrogen (–196°C) as well as with fresh pollen (control test).Results and conclusion. After 12 months of conservation under ultralow temperatures there was a change in the level of pollen viability depending on the genotype: it varied from 10.4% (cv. ‘Pozdnyaya poslevoennaya’, k-7654) to 50.4% (cv. ‘Kriviai’, k-42517), while its mean value was 0.9% higher than the mean initial viability. The fruit setting rate in the control option was 81.3–94.2%. When pollinated with pollen kept in liquid nitrogen for one year, the fruit setting rate varied from 69.2% (‘Kacha’, k-44185) to 93.3% (‘Belorusochka’, k-41978); the remaining cultivars (‘Pozdnyaya poslevoennaya’; ‘Chereshneva’, k-42481; and ‘Kriviai’) demonstrated intermediate values of this indicator, i.e., the reproductive ability of pollen after cryopreservation was high even despite its low viability. As for the fruit weight, no differences were shown by cvs. ‘Kacha’, ‘Chereshneva’ and ‘Kriviai’ in both pollination options, while this indicator in cvs. ‘Belorusochka’ and ‘Pozdnyaya poslevoennaya’ was lower than the control by 0.31 and 0.24 g, respectively