Sunspot waves and flare energy release

We address a possibility of the flare process initiation and further maintenance of its energy release due to a transformation of sunspot longitudinal waves into transverse magnetic loop oscillations with initiation of reconnection. This leads to heating maintaining after the energy release peak and formation of a flat stage on the X-ray profile. We applied the time-distance plots and pixel wavelet filtration (PWF) methods to obtain spatio-temporal distribution of wave power variations in SDO/AIA data. To find magnetic waveguides, we used magnetic field extrapolation of SDO/HMI magnetograms. The propagation velocity of wave fronts was measured from their spatial locations at specific times. In correlation curves of the 17 GHz (NoRH) radio emission we found a monotonous energy amplification of 3-min waves in the sunspot umbra before the 2012 June 7 flare. This dynamics agrees with an increase in the wave-train length in coronal loops (SDO/AIA, 171 {\AA}) reaching the maximum 30 minutes prior to the flare onset. A peculiarity of this flare time profile in soft X-rays (RHESSI, 3-25 keV) is maintaining the constant level of the flare emission for 10 minutes after the short impulse phase, which indicates at the energy release continuation. Throughout this time, we found 30-sec period transverse oscillations of the flare loop in the radio-frequency range (NoRH, 17 GHz). This periodicity is apparently related to the transformation of propagating longitudinal 3-min waves from the sunspot into the loop transverse oscillations. The magnetic field extrapolation showed the existence of the magnetic waveguide (loop) connecting the sunspot with the energy release region. A flare loop heating can be caused by the interaction (reconnections) of this transversally oscillating waveguide with the underlying twisted loops.Comment: 7 pages, 9 figure

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

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

ЕКСПЕРТНЕ ДОСЛІДЖЕННЯ ТРИЦИКЛІЧНИХ АНТИДЕПРЕСАНТІВ

Consideration is given to the methods of examining the tricyclic antidepressants (tianeptine, amitriptyline, imipramine, doxepin, clomipramine). We selected the most sensitive reagents allowing to differentiate and identify these medicines; carried out their examinations by thin-layer chromatography; selected the organic solvent systems and obtained chromatographic characteristics. The IR spectroscopy method was used to determine the main absorption bands typical for medicinal substances under examination.Розглянуто методи дослідження трициклічних антидепресантів (тіанептину, амітриптиліну, іміпраміну, доксепіну, кломіпраміну). Підібрано найбільш чутливі реактиви, що дозволяють диференціювати та ідентифікувати зазначені лікарські засоби. Проведено їх дослідження методом тонкошарової хроматографії, підібрано системи органічних розчинників і отримано хроматографічні характеристики. Методом ІЧ-спектроскопії визначено основні смуги поглинання, характерні для лікарських речовин, що досліджувалися

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

Feasibility of free space quantum key distribution with coherent polarization states

We demonstrate for the first time the feasibility of free space quantum key distribution with continuous variables under real atmospheric conditions. More specifically, we transmit coherent polarization states over a 100m free space channel on the roof of our institute's building. In our scheme, signal and local oscillator are combined in a single spatial mode which auto-compensates atmospheric fluctuations and results in an excellent interference. Furthermore, the local oscillator acts as spatial and spectral filter thus allowing unrestrained daylight operation.Comment: 12 pages, 8 figures, extensions in sections 2, 3.1, 3.2 and 4. This is an author-created, un-copyedited version of an article accepted for publication in New Journal of Physics (Special Issue on Quantum Cryptography: Theory and Practice). IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from i

Three-minute oscillations above sunspot umbra observed with SDO/AIA and NoRH

Three-minute oscillations over sunspot's umbra in AR 11131 were observed simultaneously in UV/EUV emission by SDO/AIA and in radio emission by Nobeyama Radioheliograph (NoRH). We use 24-hours series of SDO and 8-hours series of NoRH observations to study spectral, spatial and temporal variations of pulsations in the 5-9 mHz frequency range at different layers of the solar atmosphere. High spatial and temporal resolution of SDO/AIA in combination with long-duration observations allowed us to trace the variations of the cut-off frequency and spectrum of oscillations across the umbra. We found that higher frequency oscillations are more pronounced closer to the umbra's center, while the lower frequencies concentrate to the peripheral parts. We interpreted this discovery as a manifestation of variation of the magnetic field inclination across the umbra at the level of temperature-minimum. Possible implications of this interpretation for the diagnostics of sunspot atmospheres is discussed.Comment: 29 pages, 7 figures, in press ApJ, 201

Squeezed-state quantum key distribution upon imperfect reconciliation

We address the security of continuous-variable quantum key distribution with squeezed states upon realistic conditions of noisy and lossy environment and limited reconciliation efficiency. Considering the generalized preparation scheme and clearly distinguishing between classical and quantum resources, we investigate the effect of finite squeezing on the tolerance of the protocol to untrusted channel noise. For a long-distance strongly attenuating channel and the consequent low reconciliation efficiency, we show that feasible limited squeezing is surprisingly sufficient to provide the security of Gaussian quantum key distribution in the presence of untrusted noise. We explain the effect by behaviour of the Holevo quantity, which describes the information leakage, and is effectively minimized by the squeezed states.Comment: 14 pages, 7 figure

Frequency drifts of 3-min oscillations in microwave and EUV emission above sunspots

We analyse 3-min oscillations of microwave and EUV emission generated at different heights of a sunspot atmosphere, studying the amplitude and frequency modulation of the oscillations, and its relationship with the variation of the spatial structure of the oscillations. High-resolution data obtained with the Nobeyama Radioheliograph, TRACE and SDO/AIA are analysed with the use of the Pixelised Wavelet Filtering and wavelet skeleton techniques. 3-min oscillations in sunspots appear in the form of repetitive trains of the duration 8-20 min (13 min in average). The typical interval between the trains is 30-50 min. The oscillation trains are transient in frequency and power. We detected a repetitive frequency drifts of 3-min oscillations during the development of individual trains. Wavelet analysis shows three types of the frequency drift: positive, negative and fluctuations without drift. The start and end of the drifts coincide with the start time and end of the train. The comparative study of 3-min oscillations in the sequences of microwave and EUV images show the appearance of new sources of the oscillations in sunspots during the development of the trains. These structures can be interpreted as waveguides that channel upward propagating waves, responsible for 3-min oscillations. A possible explanation of the observed properties is the operation of two simultaneous factors: dispersive evolution of the upwardly-propagating wave pulses and the non-uniformity of the distribution of the oscillation power over the sunspot umbra with different wave sources corresponding to different magnetic flux tubes with different physical conditions and line-of-sight angles.Comment: 12 pages, 11 figures, submitted to A&A, 201