Quantum coherence in ion channels: Resonances, Transport and Verification

Recently it was demonstrated that long-lived quantum coherence exists during excitation energy transport in photosynthesis. It is a valid question up to which length, time and mass scales quantum coherence may extend, how to one may detect this coherence and what if any role it plays for the dynamics of the system. Here we suggest that the selectivity filter of ion channels may exhibit quantum coherence which might be relevant for the process of ion selectivity and conduction. We show that quantum resonances could provide an alternative approch to ultrafast 2D spectroscopy to probe these quantum coherences. We demonstrate that the emergence of resonances in the conduction of ion channels that are modulated periodicallly by time dependent external electric fields can serve as signitures of quantum coherence in such a system. Assessments of experimental feasibility and specific paths towards the experimental realization of such experiments are presented. We show that this may be probed by direct 2-D spectroscopy or through the emergence of resonances in the conduction of ion channels that are modulated periodically by time dependent external electric fields.Comment: Under review for New Jorunal of Physic

Superpositions of the Orbital Angular Momentum for Applications in Quantum Experiments

Two different experimental techniques for preparation and analyzing superpositions of the Gaussian and Laguerre-Gassian modes are presented. This is done exploiting an interferometric method on the one hand and using computer generated holograms on the other hand. It is shown that by shifting the hologram with respect to an incoming Gaussian beam different superpositions of the Gaussian and the Laguerre-Gaussian beam can be produced. An analytical expression between the relative phase and the amplitudes of the modes and the displacement of the hologram is given. The application of such orbital angular momenta superpositions in quantum experiments such as quantum cryptography is discussed.Comment: 18 pages, 4 figures. to appear in Journal of Optics

Edge-guided image gap interpolation using multi-scale transformation

This paper presents improvements in image gap restoration through the incorporation of edge-based directional interpolation within multi-scale pyramid transforms. Two types of image edges are reconstructed: 1) the local edges or textures, inferred from the gradients of the neighboring pixels and 2) the global edges between image objects or segments, inferred using a Canny detector. Through a process of pyramid transformation and downsampling, the image is progressively transformed into a series of reduced size layers until at the pyramid apex the gap size is one sample. At each layer, an edge skeleton image is extracted for edge-guided interpolation. The process is then reversed; from the apex, at each layer, the missing samples are estimated (an iterative method is used in the last stage of upsampling), up-sampled, and combined with the available samples of the next layer. Discrete cosine transform and a family of discrete wavelet transforms are utilized as alternatives for pyramid construction. Evaluations over a range of images, in regular and random loss pattern, at loss rates of up to 40%, demonstrate that the proposed method improves peak-signal-to-noise-ratio by 1–5 dB compared with a range of best-published works

Angular Schmidt Modes in Spontaneous Parametric Down-Conversion

We report a proof-of-principle experiment demonstrating that appropriately chosen set of Hermite-Gaussian modes constitutes a Schmidt decomposition for transverse momentum states of biphotons generated in the process of spontaneous parametric down conversion. We experimentally realize projective measurements in Schmidt basis and observe correlations between appropriate pairs of modes. We perform tomographical state reconstruction in the Schmidt basis, by direct measurement of single-photon density matrix eigenvalues.Comment: 5 pages, 4 figure

Experimental design and wastewater filtration assessment of a biodegradable Poly (isobornyl methacrylate) (PIBMA)/Hypromellosemembrane

In this study, the optimization and characterization of the novel asymmetric membranes of poly(isobornyl methacrylate) (PIBMA)/Hypromellose were done using full factorial experimental design. The asymmetric membranes of (PIBMA)/ Hypromellosewere prepared using immersion precipitation technique. The (PIBMA)/ Hypromellose mass ratios and non-solvents used in coagulation bath were regarded as factors in the optimization and effects of them were investigated on the membrane performance. The membranes characterized by contact angle, scanning electron microscopy (SEM),atomic force microscopy (AFM) and X-ray diffraction (XRD). The experimental results elucidated that the modified membranes exhibit significant differences in surface properties and inherent properties due to Hypromellose addition. Also,a substantial increase in mechanical properties and resistance of membranes was observed for the poly (isobornyl methacrylate) membranes cast in isopropanol coagulation bath at (PIBMA) /Hypromellosemass ratio of  50/50(w/w). These membranes have more comprehensive potential to reject pollution indices properly than others

A mathematical model for determining the best process conditions for average Molecular weight and melt flow index of polypropylene

The present work describes a mathematical model based on a population balance approach for determining the effect of the reaction temperature and hydrogen amount on the vital final product properties including average molecular weight and polydispersity index and flow index of polypropylene and also the profile rate of the polymerization. The aim of this study was to find the best operating condition through a model which is validated by the experimental data. The software program was coded in MATLAB/SIMULINK. The model profile rates compared with the experimental results to show the accuracy of the model. In this study, it was concluded that increasing the reaction temperature until a certain limit is useful and improve some indices of the final product and after that rising the reaction temperature has a harmful effect on the indices. Exactly the same issue is true in the case of increasing the amount of hydrogen.               KEY WORDS: Mathematical modeling, Propylene polymerization, Melt flow index, Population balance, Average molecular weight, hydrogen Bull. Chem. Soc. Ethiop. 2019, 33(1), 169-182DOI: https://dx.doi.org/10.4314/bcse.v33i1.1

Experimental Quantum Cryptography with Qutrits

We produce two identical keys using, for the first time, entangled trinary quantum systems (qutrits) for quantum key distribution. The advantage of qutrits over the normally used binary quantum systems is an increased coding density and a higher security margin. The qutrits are encoded into the orbital angular momentum of photons, namely Laguerre-Gaussian modes with azimuthal index l +1, 0 and -1, respectively. The orbital angular momentum is controlled with phase holograms. In an Ekert-type protocol the violation of a three-dimensional Bell inequality verifies the security of the generated keys. A key is obtained with a qutrit error rate of approximately 10 %.Comment: New version includes additional references and a few minor changes to the manuscrip

Polarization control of single photon quantum orbital angular momentum states

The orbital angular momentum of photons, being defined in an infinitely dimensional discrete Hilbert space, offers a promising resource for high-dimensional quantum information protocols in quantum optics. The biggest obstacle to its wider use is presently represented by the limited set of tools available for its control and manipulation. Here, we introduce and test experimentally a series of simple optical schemes for the coherent transfer of quantum information from the polarization to the orbital angular momentum of single photons and vice versa. All our schemes exploit a newly developed optical device, the so-called "q-plate", which enables the manipulation of the photon orbital angular momentum driven by the polarization degree of freedom. By stacking several q-plates in a suitable sequence, one can also access to higher-order angular momentum subspaces. In particular, we demonstrate the control of the orbital angular momentum $m$ degree of freedom within the subspaces of $|m|=2 \hbar$ and $|m|=4\hbar$ per photon. Our experiments prove that these schemes are reliable, efficient and have a high fidelity.Comment: 9 pages, 8 figure

Photon Orbital Angular Momentum and Mass in a Plasma Vortex

We analyse the Anderson-Higgs mechanism of photon mass acquisition in a plasma and study the contribution to the mass from the orbital angular momentum acquired by a beam of photons when it crosses a spatially structured charge distribution. To this end we apply Proca-Maxwell equations in a static plasma with a particular spatial distribution of free charges, notably a plasma vortex, that is able to impose orbital angular momentum (OAM) onto light. In addition to the mass acquisition of the conventional Anderson-Higgs mechanism, we find that the photon acquires an additional mass from the OAM and that this mass reduces the Proca photon mass.Comment: Four pages, no figures. Error corrections, improved notation, refined derivation