Ultrasensitive 3He magnetometer for measurements of high magnetic fields

We describe a 3He magnetometer capable to measure high magnetic fields (B > 0.1 Tesla) with a relative accuracy of better than 10^-12. Our approach is based on the measurement of the free induction decay of gaseous, nuclear spin polarized 3He following a resonant radio frequency pulse excitation. The measurement sensitivity can be attributed to the long coherent spin precession time T2* being of order minutes which is achieved for spherical sample cells in the regime of motional narrowing where the disturbing influence of field inhomogeneities is strongly suppressed. The 3He gas is spin polarized in-situ using a new, non-standard variant of the metastability exchange optical pumping. We show that miniaturization helps to increase T2* further and that the measurement sensitivity is not significantly affected by temporal field fluctuations of order 10^-4.Comment: 27 pages, 7 figure

Features of sugar beet hybrids productivity formation depending on agrotechnological measures

The thesis being presented are theoretical generalization and new solution of scientific problems – the sugar beet productivity increasing by applying of complex agrotechnological measures of growing that directed on ensuring of the maximum productivity and roots high technological qualities. Based on extensive experimental researches and obtained results is revealed the following, there is no significant differences of occurrence of shoots intensity depending on the hybrids of domestic and foreign origin and therefore - no significant difference from field germination of seed. The dynamics of occurrence of shoots intensity and field germination of seed are influenced on the density of sugar beet plants. Under the conditions of uniform placement of sugar beet plant hybrids in a row and full use of complex agrotechnological measures is formed the optimal area of plant nutrition that promotes proper formation of roots and a powerful leaf mass, and ultimately influence on their productivity. Complex research that included two highly productive hybrid Ukrainian ChS 72 - domestic and Leopard - of foreign origins, optimum plant density before harvest - 100-110 thousand/ha and double foliar feeding on the background of the main fertilizer - in the closing leaves phase + in the closing leaves line in rows phase (136 days from sowing) is confirmed the high efficiency of the studied measures

Strong secrecy in wireless network coding systems with M-QAM modulators

We investigate the possibility of developing physical layer network coding (PNC) schemes with embedded strong secrecy based on standard QAM modulators. The proposed scheme employs a triple binning approach at the QAM front-end of the wireless PNC encoders. A constructive example of a strong secrecy encoder is presented when a BPSK and an 8-PAM modulator are employed at the wireless transmitters and generalized to arbitrary M-QAM modulators, assuming channel inversion is attainable at the first cycle of the transmission. Our preliminary investigations demonstrate the potential of using such techniques to increase the throughput while in parallel not compromise the confidentiality of the exchanged data

О СТАРШЕМ ПОКАЗАТЕЛЕ ЛЯПУНОВА ЛИНЕЙНОЙ ДИФФЕРЕНЦИАЛЬНОЙ СИСТЕМЫ С ПАРАМЕТРОМ-МНОЖИТЕЛЕМ КАК ФУНКЦИИ ПАРАМЕТРА

The largest Lyapunov exponents of linear differential systems dx/ dt = µA(t)x, xєℝn, t ≥0, with a real parameter-multiplier as a function of the parameter are considered. It is proved that the largest Lyapunov exponent is a function of a Baire class (*,G⅋), which vanishes at zero and satisfies one of the two cases: 1) it exceeds the linear function; 2) it is equal to the plus infinity on some real semi-axis. In the first case, the sufficiency of the given necessary conditions is proved.Рассматриваются старшие показатели Ляпунова линейных дифференциальных систем dx/ dt = µA(t)x, xєℝn, t ≥0, с кусочно-непрерывными коэффициентами и вещественным параметром-множителем как функции параметра. В работе доказано, что старший показатель Ляпунова является функцией, такой, что прообраз любого бесконечного полуинтервала, замкнутого слева, является G⅋-множеством вещественной оси, равной нулю в нуле и удовлетворяющей вещественных полуосей она тождественно равна плюс бесконечности. В первом случае доказана достаточность приведенных необходимых условий

Measurement of the Permanent Electric Dipole Moment of the 129^{129}Xe Atom

We report on a new measurement of the CP-violating permanent Electric Dipole Moment (EDM) of the neutral $^{129}$Xe atom. Our experimental approach is based on the detection of the free precession of co-located nuclear spin-polarized $^3$He and $^{129}$Xe samples. The EDM measurement sensitivity benefits strongly from long spin coherence times of several hours achieved in diluted gases and homogeneous weak magnetic fields of about 400~nT. A finite EDM is indicated by a change in the precession frequency, as an electric field is periodically reversed with respect to the magnetic guiding field. Our result, $\left(-4.7\pm6.4\right)\cdot 10^{-28}$ ecm, is consistent with zero and is used to place a new upper limit on the $^{129}$Xe EDM: $|d_\text{Xe}|<1.5 \cdot 10^{-27}$ ecm (95% C.L.). We also discuss the implications of this result for various CP-violating observables as they relate to theories of physics beyond the standard model

ПОЛНОЕ ОПИСАНИЕ СТАРШЕГО ПОКАЗАТЕЛЯ ЛЯПУНОВА ЛИНЕЙНОЙ ДИФФЕРЕНЦИАЛЬНОЙ СИСТЕМЫ С ПАРАМЕТРОМ-МНОЖИТЕЛЕМ

The largest Lyapunov exponents of linear differential systems dx/dt = μA(t)x,  x∈Rn, t ≥ 0 with the real parameter-multiplier μ are considered. It is proven that a function ƒ: R→R̅   is the largest Lyapunov exponent of some linear differential system with а real parameter-multiplier if and only if it fits the next four conditions: 1) it belongs to the (*,Gδ)  Baire class; 2) it vanishes at zero; 3) it is nonnegative on some real semi-axis; 4) if it is not identically equal to +∞ on any real semi-axis, then there exists such a real number b that the inequality ƒ(μ) ≥ bμ holds for all μ∈R.Для семейства dx/dt = μA(t)x,  x∈Rn, t ≥ 0 линейных n-мерных дифференциальных систем с кусочно-непрерывной матрицей A(t), t≥0, и вещественным параметром μ получено для любого натурального n полное описание старшего показателя Ляпунова его систем, рассматриваемого как функция параметра μ. Доказано, что функция ƒ: R→R̅   является старшим показателем Ляпунова некоторого такого семейства, если и только если она удовлетворяет четырем условиям: 1) принадлежит бэровскому классу (*, Gδ);2) равна нулю в нуле; 3) неотрицательна на некоторой полуоси; 4) если она не равна тождественно +∞ ни на одной из открытых полуосей, то существует действительное число b такое, что неравенство ƒ(μ) ≥ bμ выполняется при всех μ∈

Precise Measurement of Magnetic Field Gradients from Free Spin Precession Signals of 3^{3}He and 129^{129}Xe Magnetometers

We report on precise measurements of magnetic field gradients extracted from transverse relaxation rates of precessing spin samples. The experimental approach is based on the free precession of gaseous, nuclear spin polarized $^3$He and $^{129}$Xe atoms in a spherical cell inside a magnetic guiding field of about 400 nT using LT$_C$ SQUIDs as low-noise magnetic flux detectors. The transverse relaxation rates of both spin species are simultaneously monitored as magnetic field gradients are varied. For transverse relaxation times reaching 100 h, the residual longitudinal field gradient across the spin sample could be deduced to be$|\vec{\nabla}B_z|=(5.6 \pm 0.4)$ pT/cm. The method takes advantage of the high signal-to-noise ratio with which the decaying spin precession signal can be monitored that finally leads to the exceptional accuracy to determine magnetic field gradients at the sub pT/cm scale

Ensuring the Complex Environmental Management: Goals, Objectives and Regional Features

The article is aimed at developing theoretical and methodological approaches to identification of the basic components of the complex environmental management and ensuring their complementarity with the Goals of sustainable development for 2016–2030; definition of objectives and tasks of complex environmental management in the context of ensuring ecological-economic and social efficiency of natural resource potential development, as well as specification of the objectives of complex environmental management in the separately taken region. As a result of research the basic components of complex environmental management are defined. The main production-economic, socio-economic and ecological-economic goals of complex environmental management are characterized. It is proved that complex environmental management covers a set of industrial-technical and organizational-economic measures aimed at maximizing the benefit from economic development of natural resource potential at all phases of reproduced circuits without damaging the nature. Methods and technologies of complex environmental management are proposed

Limit on Lorentz and CPT violation of the bound Neutron Using a Free Precession 3He/129Xe co-magnetometer

We report on the search for Lorentz violating sidereal variations of the frequency difference of co-located spin-species while the Earth and hence the laboratory reference frame rotates with respect to a relic background field. The co-magnetometer used is based on the detection of freely precessing nuclear spins from polarized 3He and 129Xe gas samples using SQUIDs as low-noise magnetic flux detectors. As result we can determine the limit for the equatorial component of the background field interacting with the spin of the bound neutron to be bn < 3.7 x 10^{-32} GeV (95 C.L.).Comment: 5 pages, 4 figure

Test of Lorentz Symmetry by using a 3He/129Xe Co-Magnetometer

To test Lorentz symmetry we used a 3He/129Xe co-magnetometer. We will give a short summary of our experimental setup and the results of our latest measurements. We obtained preliminary results for the equatorial component of the background field interacting with the spin of the bound neutron: b_n < 3.72 x 10^(-32) GeV (95 C.L.).Comment: Presented at the Fifth Meeting on CPT and Lorentz Symmetry, Bloomington, Indiana, June 28 - July 2, 201