Quantum uniqueness

In the classical world one can construct two identical systems which have identical behavior and give identical measurement results. We show this to be impossible in the quantum domain. We prove that after the same quantum measurement two different quantum systems cannot yield always identical results, provided the possible measurement results belong to a non orthogonal set. This is interpreted as quantum uniqueness - a quantum feature which has no classical analog. Its tight relation with objective randomness of quantum measurements is discussed.Comment: Presented at 4th Feynman festival, June 22-26, 2009, in Olomouc, Czech Republic

Informational completeness of continuous-variable measurements

We justify that homodyne tomography turns out to be informationally complete when the number of independent quadrature measurements is equal to the dimension of the density matrix in the Fock representation. Using this as our thread, we examine the completeness of other schemes, when continuous-variable observations are truncated to discrete finite-dimensional subspaces.Comment: To appear in Phys. Rev.

EUV jets, type III radio bursts and sunspot waves investigated using SDO/AIA observations

Images from the Solar Dynamics Observatory (SDO) at 211A are used to identify the solar source of the type III radio bursts seen in WIND/WAVES dynamic spectra. We analyse a 2.5 hour period during which six strong bursts are seen. The radio bursts correlate very well with the EUV jets coming from the western side of a sunspot in AR11092. The EUV jet emission also correlates well with brightening at what looks like their footpoint at the edge of the umbra. For 10-15 min after strong EUV jets are ejected, the footpoint brightens at roughly 3 min intervals. In both the EUV images and the extracted light curves, it looks as though the brightening is related to the 3-min sunspot oscillations, although the correlation coefficient is rather low. The only open field near the jets is rooted in the sunspot. We conclude that active region EUV/X-ray jets and interplanetary electron streams originate on the edge of the sunspot umbra. They form along a current sheet between the sunspot open field and closed field connecting to underlying satellite flux. Sunspot running penumbral waves cause roughly 3-min jet footpoint brightening. The relationship between the waves and jets is less clear.Comment: 4 pages, 7 figures, Accepted by A&A Letters. For associated gif movie, see http://www.mps.mpg.de/data/outgoing/innes/jets/losb_304_211_rd.gi

Coherent State Quantum Key Distribution with Multi Letter Phase-Shift Keying

We present a protocol for quantum key distribution using discrete modulation of coherent states of light. Information is encoded in the variable phase of coherent states which can be chosen from a regular discrete set ranging from binary to continuous modulation, similar to phase-shift-keying in classical communication. Information is decoded by simultaneous homodyne measurement of both quadratures and requires no active choice of basis. The protocol utilizes either direct or reverse reconciliation, both with and without postselection. We analyze the security of the protocol and show how to enhance it by the optimal choice of all variable parameters of the quantum signal.Comment: 11 pages, 2 figures, 1 table. Comments welcom

ОБЛІКОВО-АНАЛІТИЧНЕ ЗАБЕЗПЕЧЕННЯ ФІНАНСОВИХ РЕЗУЛЬТАТІВ ДІЯЛЬНОСТІ ДЛЯ ВИРОБНИЧИХ ПІДПРИЄМСТВ

The article is devoted to the study of methodology and organization of accounting and analytical support of financial results for the production enterprises in Ukraine. Principles and functions of accounting and analytical support, compliance with which contributes to the reliability, timeliness and completeness of such information format are generalized. Methodical approaches to management accounting and management analysis, factors of formation of the necessary level of detailing for management information, its compliance with the management’s specific requests are disclosed. Modern information technologies for processing and transmitting accounting and analytical data that based on a wide range of input flows and the variability of management requirements with a view to achieving the effectiveness of socio-economic and environmental trends of economic activity are considered. The organizational approaches to the processing and transmission of such information with using modern information technology which enable us to ensure the usefulness of disclosure in the work of accounting and analytical support of financial results of the activities for manufacturing enterprises are proposed.Статья посвящена изучению методики и организации учетно-аналитического обеспечения финансовых результатов для производственных предприятий Украины. Обобщены принципы и функции учетно-аналитического обеспечения, соблюдение которых способствует достижению достоверности, оперативности и полноты такого информационного формата. Раскрыты методические подходы к управленческому учету и управленческому анализу, факторы формирования необходимого уровня детализации управленческой информации, ее соответствия целевым запросам менеджмента. Рассмотрены современные информационные технологии обработки и передачи учетно-аналитических данных на основе широкого спектра входных потоков и вариативности требований управленцев с целью достижения результативности социально-экономического и экологического направлений хозяйственной деятельности.Стаття присвячена вивченню методики та організації обліково-аналітичного забезпечення фінансових результатів для виробничих підприємств України. Узагальнено принципи та функції обліково-аналітичного забезпечення, дотримання яких сприяє досягненню достовірності, оперативності та повноти такого інформаційного формату. Розкрито методичні підходи до управлінського обліку та управлінського аналізу, фактори формування необхідного рівня деталізації управлінської інформації, ї відповідності цільовим запитам менеджменту. Розглянуто сучасні інформаційні технології обробки та передачі обліково-аналітичних даних з урахуванням широкого спектру вхідних потоків та варіативності вимог управлінців, що уможливлює досягнення результативності соціально-економічного та екологічного напрямків господарської діяльності

Theory and Applications of Non-Relativistic and Relativistic Turbulent Reconnection

Realistic astrophysical environments are turbulent due to the extremely high Reynolds numbers. Therefore, the theories of reconnection intended for describing astrophysical reconnection should not ignore the effects of turbulence on magnetic reconnection. Turbulence is known to change the nature of many physical processes dramatically and in this review we claim that magnetic reconnection is not an exception. We stress that not only astrophysical turbulence is ubiquitous, but also magnetic reconnection itself induces turbulence. Thus turbulence must be accounted for in any realistic astrophysical reconnection setup. We argue that due to the similarities of MHD turbulence in relativistic and non-relativistic cases the theory of magnetic reconnection developed for the non-relativistic case can be extended to the relativistic case and we provide numerical simulations that support this conjecture. We also provide quantitative comparisons of the theoretical predictions and results of numerical experiments, including the situations when turbulent reconnection is self-driven, i.e. the turbulence in the system is generated by the reconnection process itself. We show how turbulent reconnection entails the violation of magnetic flux freezing, the conclusion that has really far reaching consequences for many realistically turbulent astrophysical environments. In addition, we consider observational testing of turbulent reconnection as well as numerous implications of the theory. The former includes the Sun and solar wind reconnection, while the latter include the process of reconnection diffusion induced by turbulent reconnection, the acceleration of energetic particles, bursts of turbulent reconnection related to black hole sources as well as gamma ray bursts. Finally, we explain why turbulent reconnection cannot be explained by turbulent resistivity or derived through the mean field approach.Comment: 66 pages, 24 figures, a chapter of the book "Magnetic Reconnection - Concepts and Applications", editors W. Gonzalez, E. N. Parke

Applicability of QKD: TerraQuantum view on the NSA's scepticism

Quantum communication offers unique features that have no classical analog, in particular, it enables provably secure quantum key distribution (QKD). Despite the benefits of quantum communication are well understood within the scientific community, the practical implementations sometimes meet with scepticism or even resistance. In a recent publication [1], NSA claims that QKD is inferior to "quantum-resistant" cryptography and does not recommend it for use. Here we show that such a sceptical approach to evaluation of quantum security is not well justified. We hope that our arguments will be helpful to clarify the issue